⃝charles j byrne] lunar orbiter photographic atla

Lunar Orbiter Photographic Atlas of theNear Side of the Moon

Charles J. Byrne

Lunar OrbiterPhotographic Atlas ofthe Near Side of theMoon

With 619 Illustrations and a CD-ROM

Charles J. ByrneImage AgainMiddletown, NJUSA

Cover illustration: Earth-based photograph of the full Moon from the “Consolidated Lunar Atlas” onthe Website of the Lunar and Planetary Institute.

British Library Cataloging-in-Publication DataByrne, Charles J., 1935–

Lunar Orbiter photographic atlas of the near side of the Moon1. Lunar Orbiter (Artificial satellite) 2. Moon–Maps 3. Moon–Photographs from spaceI. Title523.3 0223

ISBN 1852338865

Library of Congress Cataloging-in-Publication DataByrne, Charles J., 1935–

Lunar Orbiter photographic atlas of the near side of the Moon : with 619 figures / Charles J. Byrne.

p. cm.Includes bibliographical references and index.ISBN 1-85233-886-5 (acid-free paper)1. Moon–Maps. 2. Moon–Photographs from space. 3. Moon–Remote-sensing images.

4. Lunar Orbiter (Artificial satellite) I. Title.G1000.3.B9 2005523.3 022 3–dc22 2004045006

ISBN 1-85233-886-5 Printed on acid-free paper.

© 2005 Springer-Verlag London LimitedApart from any fair dealing for the purposes of research or private study, or criticism, or review, aspermitted under the Copyright, Designs and Patents Act 1988, this publication may only be repro-duced, stored or transmitted, in any form or by any means, with the prior permission in writing of thepublishers, or in the case of reprographic reproduction in accordance with the terms of licenses issuedby the Copyright Licensing Agency. Enquiries concerning reproduction outside those terms should besent to the publishers.The use of registered names, trademarks, etc, in this publication does not imply, even in the absenceof a specific statement, that such names are exempt from the relevant laws and regulations and there-fore free for general use.

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Preface

The Moon is Earth’s nearest neighbor. Since the dawn of intelligence, our eyeshave seen the Moon, puzzling over its shady figures, its phases, its motions in thesky, and its relation to tides. Even the smallest telescopes resolve the shadowsinto a heavily cratered surface, stimulating the imagination. Each advance of theastronomer’s art has revealed new insights into the nature of the lunar surface,until curiosity and competition led the American and Russian space programs tosend orbital cameras, robotic landers and rovers, and the Apollo astronaut explo-ration teams to the Moon.

The Lunar Orbiter program, a series of five photographic spacecraft launchedin 1966 and 1967, was motivated by the need to find and certify safe and interest-ing landing sites for the Apollo spacecraft. When the Lunar Orbiter program wasstarted (1964), no spacecraft had landed on the Moon, but the Apollo programwas committed to safely land the Lunar Module, with two astronauts on board. Atthe time, I was working in the lunar environment group of Bellcomm, Inc. AT&Testablished Bellcomm at the request of the National Aeronautics and SpaceAdministration (NASA) to support the Apollo project headquarters group. Ourresponsibility included the challenging assignment of finding a safe landing sitefor a vehicle about the size of a helicopter, with a half-meter (0.5-m, 20-inch)ground clearance and limited ability to land on a slope. Of course, we had verylittle information about the lunar surface at such scales. There was some informa-tion from lunar photometry and radar scatter measurements, but there werestrong uncertainties about what aspects of the surface were being measured; inparticular, the soil strength was an unknown. Speculation raised possibilities ofdust floated by static electricity or fragile glasslike lava.

The requirements for Lunar Orbiter were established to achieve the best possi-ble resolution within the state of the art and to obtain imagery of that resolutionover a significant percentage of the area available for Apollo landings. TargetedApollo landing sites had to be as smooth as possible over a large enough area toaccommodate the down-range and cross-range navigation errors, determined bythe tracking, and control uncertainties associated with factors such as the largelyunknown gravity anomalies.

NASA’s Langley Research Center was chosen to manage the Lunar Orbiterprogram. I had the pleasure of drafting the specifications and participating in theselection of contractors. The resulting spacecraft and camera designs of BoeingAircraft and Eastman Kodak (respectively) were capable of enormous data collec-tion capacity, even in today’s terms. All together, about 1000 pairs of medium-and high-resolution exposures were made during the five missions. The negativeswere developed in orbit, scanned, and transmitted to photographic and magnetictape recorders in the three stations of the Deep Space Network operated by the JetPropulsion Laboratory (JPL) in California, Spain, and Australia. Each exposureresults in one medium-resolution frame and one long high-resolution frame,usually presented as three subframes.

Although five missions were planned to compensate for possible failures, eitherof spacecraft or rejection of initial target sites, the survey for early Apollo landingsites was completed in the first three missions. As a result, the fourth mission wasused for a comprehensive survey of the near side of the Moon; these are the pho-tographs that are the primary contents of this book. The fifth mission examinedmany scientific sites at very high resolution, surveyed a few additional landingsites for later Apollo missions, and improved coverage of the far side of theMoon. Since the Lunar Orbiter missions returned their extensive photographic

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coverage of Earth’s Moon, the pictures have been the basic reference for high-resolution topographic information. The most often referenced images are thecomprehensive set of about 600 images selected by Bowker (1971) and the nearside set of about 450 images selected by Whitaker (1970).

Following the thorough coverage of the Lunar Orbiter program, the ApolloCommand and Service Module, in orbit during landing missions, provided addi-tional coverage of the equatorial regions with its mapping and panoramiccameras. The Clementine mission provided a comprehensive survey of altitude,albedo (intrinsic brightness), and multispectral data in 1994. Lunar Prospectorprovided gamma ray spectroscopy in 1998. The data from these spacecraft hasadded insight into the mineral composition of nearly all the lunar surface,extending surveys of the equatorial region by Apollo. The interpretation of theremote sensing data has been supported by ground truth from analysis of lunarrocks and soil returned by Apollo and Luna missions. Despite the advances ofthese later missions, the Lunar Orbiter photographs, taken at a low sun angle,remain the primary source of topographic images and are used extensively incurrent scientific presentations, papers, and books.

At the time of Lunar Orbiter’s design, image scanning technology was muchless advanced than it is today. The methods used resulted in artifacts in theimages that distract a viewer. Scanning and transmission limitations required thesubframes to be reassembled from 20 to 30 framelets of 35-millimeter film. Thereare fine bright lines running across each subframe between the framelets, andthere are brightness variations from the spacecraft’s scanner that appear asstreaks within the framelets. The artifacts are particularly distracting when theimages are printed at high contrast to show subtle topographic features andbrightness variations. Lunar scientists have become used to these artifacts, butthey detract from their value to students and casual observers.

Since the first photos were received, I have wanted to clean up the scanningartifacts, but at the time it would have been very expensive. The priorities were toexamine the photos and start using them, rather than to improve their visualquality. Advances in the art of computation and the capacity of modern comput-ers have enabled processing of the photos to remove nearly all the scanning arti-facts, resulting in clear images that are much easier to view. Drawing on anunderstanding of the nature of the artifacts, I have written programs thatmeasure and compensate for the systematic artifacts and in addition applyfiltering techniques similar to those published by Lisa Gaddis of the United StatesGeological Survey (USGS) (Gaddis, 2001).

Lunar Orbiter photography has been archived as hard copy photographs, eachabout 60 centimeters (cm) (about 2 feet) wide, at each NASA Regional PlanetaryImage Facility, including one at the Lunar and Planetary Institute (LPI) inHouston, Texas. LPI has digitized this important archival source and publishedthe images in the Digital Lunar Orbiter Photographic Atlas of the Moon on theLPI web site (www.lpi.usra.edu/research/lunar_orbiter/). Further, the LPI staffhas added annotations to the photos, clearly outlining many of the features andlabeling them with their internationally recognized names.

A team led by Jeff Gillis carried out this important work; Jeff was supported byWashington University at St. Louis and LPI. He is currently with the University ofHawaii. LPI technical and administrative support was provided by Michael S.O’Dell, Debra Rueb, Mary Ann Hager, and James A. Cowan with assistance fromSandra Cherry, Mary Cloud, Renee Dotson, Kin Leung, Jackie Lyon, Mary Noel,Barbara Parnell, and Heather Scott. The selection of photos on the LPI DigitalArchive is that selected for Lunar Orbiter Photographic Atlas of the Moon byBowker and Hughes (see the reference section for details).

The annotated photos in this atlas provide full coverage of the near side,including nearly all the features whose names have been approved by theInternational Astronomical Union (IAU). All the high- and medium-resolutionphotos of Lunar Orbiter 4 (except for a few that were found unacceptable forBowker, 1971) have been cleaned and are in the enclosed compact disc. Most ofthese, selected for nonredundancy and interest of features, are printed along withthe annotated photos. All the photos (before processing by the author) are cour-tesy of NASA and LPI.

Photos with annotated overlays label the major features within each of thephotos, including the landing sites of manned and unmanned spacecraft. These

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overlays were extracted digitally from those published by LPI. I added additionalannotations to provide latitude, longitude, and scale information and also to bringthe set of features up to date with the Gazetteer of Planetary Nomenclature, the list maintained for the IAU by the United States Geological Survey (USGS)Astrogeology Program. Notes with each photo point out salient aspects of the fea-tures. The combination of cleaned photos, labeled features, and notes are intendedto serve as powerful aids to learning the geography and geology of the near side ofthe Moon as well as valuable reference material.

Throughout the project of cleaning the photos and writing this book, helpfulsuggestions and comments were made by Jeff Gillis, Mary Ann Hager, PaulSpudis, Lisa Gaddis, Debbie Martin, Michael Martin, Ewen Whitaker, and BradJolliff.

My dear wife Mary worked long and patiently as system administrator, pictureprocessor, and reviewer.

Special gratitude goes to Don Wilhelms, USGS Astrogeology (retired), whosebooks have been major sources and who was kind enough to review this bookand set me straight on lunar geology.

Charles J. Byrne

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Table of Contents

1. Overview of the Atlas ........................................................................................ 11.1. Content...................................................................................................... 11.2. How to Use This Atlas ............................................................................ 11.3. Large-Scale Maps .................................................................................... 2

2. Lunar Orbiter Mission 4.................................................................................... 52.1. The Mission .............................................................................................. 52.2. Mission Design ........................................................................................ 52.3. The Cameras ............................................................................................ 52.4. The Film .................................................................................................... 52.5. Scanning and Reconstruction ................................................................ 72.6. Scanning Artifacts.................................................................................... 72.7. Cleaning the Images ................................................................................ 7

3. Overview of the Near Side of the Moon .......................................................... 83.1. Origin of the Moon .................................................................................. 83.2. The Near Side Versus the Far Side ........................................................ 83.3. Mare and Highlands ................................................................................ 83.4. Basins ........................................................................................................ 93.5. Landmarks for Geography ...................................................................... 93.6. Descriptions of Landmark Regions ........................................................ 9

Orientale Basin Region .......................................................................... 10Humorum Basin Region........................................................................ 10Imbrium Basin Region .......................................................................... 10Nectaris Basin Region............................................................................ 10Serenitatis Basin Region........................................................................ 10Eastern Basins Region .......................................................................... 10North Polar Region ................................................................................ 10South Polar Region ................................................................................ 10

3.7. The Ages of the Lunar Features ............................................................ 10Estimating Ages...................................................................................... 10Named Age Ranges ................................................................................ 10

4. Organization of the Photos ............................................................................ 114.1. Grouping by Landmark Regions .......................................................... 114.2. Order: West to East and South to North .............................................. 114.3. Clean and Annotated Images ................................................................ 114.4. High-Resolution Frames and Subframes ............................................ 114.5. Discussion Notes.................................................................................... 114.6. Enclosed Compact Disc (CD)................................................................ 11

5. Orientale Basin Region .................................................................................. 135.1. Overview ................................................................................................ 13

Orientale, the Archetype Multi-Ringed Basin .................................... 13Crater Morphology as a Function of Size ............................................ 14Surroundings of the Orientale Basin.................................................... 14

5.2. High-Resolution Images........................................................................ 14

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6. Humorum Basin Region ................................................................................ 556.1. Overview ................................................................................................ 55

Basins, Maria, and Highlands .............................................................. 55Apollo Landings .................................................................................... 56

6.2. High-Resolution Images........................................................................ 56

7. Imbrium Basin Region.................................................................................. 1007.1. Overview .............................................................................................. 100

The Imbrium Basin.............................................................................. 100Oceanus Procellarum .......................................................................... 100Fra Mauro Formation .......................................................................... 101

7.2. High-Resolution Images...................................................................... 102

8. Nectaris Basin Region .................................................................................. 1558.1. Overview .............................................................................................. 155

Basins, Maria, and Highlands ............................................................ 155Apollo Landing .................................................................................... 156

9. Serenitatis Basin Region .............................................................................. 2009.1. Overview .............................................................................................. 200

Serenitatis Basin .................................................................................. 201Apollo Landings .................................................................................. 201

10. Eastern Basins Region .................................................................................. 24410.1. Overview .............................................................................................. 244

The Crisium Basin................................................................................ 244The Australe Basin .............................................................................. 244The Smythii Basin ................................................................................ 244

11. North Polar Region ...................................................................................... 26311.1. Overview .............................................................................................. 263

Mare Frigoris ........................................................................................ 263The Humboldtianum Basin ................................................................ 264The North Polar Highlands ................................................................ 264The North Pole .................................................................................... 264

12. South Polar Region........................................................................................ 29112.1. Overview .............................................................................................. 291

Western Sector of the South Polar Region ........................................ 291Central Sector of the South Polar Region .......................................... 291Eastern Sector of the South Polar Region .......................................... 291The South Pole .................................................................................... 291

Glossary .................................................................................................................. 323

References .............................................................................................................. 324

General Index ........................................................................................................ 325

IAU Named Features .............................................................................................. 327

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1.1. ContentThe atlas presents full coverage of the nearside of the Moonwith a series of photos all taken from orbit by LunarOrbiter 4, with a nearly vertical viewpoint and sunlight at approximately 20 degrees (°) from the horizontal.Extensive computer processing has been used to improvethe quality of these photos. Features whose names havebeen recognized by the International Astronomical Union(IAU) have been identified on an overlay and listed in theindex of features. Notes on each page discuss the geologicprocesses that formed the features and controlled theirinteractions.

The high-resolution photos of this book typically coverabout 200 by 300 kilometers (km). Approximately 350 ofthese photos cover the nearside of the Moon (with someoverlap). The photos are grouped into chapters that eachpresent one of the regions of the Moon. Six of these regionshave been selected to focus on basins of the Moon, thelargest coherent lunar features. Chapters on the North andSouth Polar Regions complete the coverage of the nearside.Figure 1.1 identifies these regions against the background ofa photograph of the full Moon. Figure 1.2 identifies theregions of the central latitudes against a Mercator projectionmap, Figure 1.3 shows the North Polar Region, and Figure 1.4shows the South Polar Region.

An introduction to each chapter surveys the relevantregion, using wide coverage photos. An overview of thegeology of each region and its features introduces the spe-cialized vocabulary needed to describe lunar processes. Eachchapter provides a guide to the high-resolution photos as anaid to relating them to the wide-angle views and to the Moonas a whole. Each high-resolution photo is marked with thelatitude and longitude as a further guide to locating featureson the maps of Figures 1.2 to 1.4.

An enclosed compact disc (CD) contains all the cleaned-up photographs of Lunar Orbiter Mission 4, with an indexlisting all the officially named lunar features shown in thisbook. These photos, when viewed on a monitor with appro-priate magnification, show more detail than can be seen inthe printed pictures.

1.2. How to Use This AtlasA telescopic observer or photographer of the Moon, workingat high resolution, views a small area under lighting thatvaries both with time and with position. The angle of view isnearly vertical at the center of the Moon as we see it, but se-verely foreshortened near the limb (edge of the visibleMoon). One might ask: What features are in the area? Howdo they relate to the rest of the Moon? How would the featurelook relative to others if seen at similar lighting conditionsand viewing angles? What is the current understanding of theprocesses that formed these features?

The following is a summary of how an interested observermight answer these questions, with the aid of this atlas:

1. Relate a feature viewed in a telescope, photo, or electronicimage to its position on the full Moon photo of Figure 1.1.

2. Note the region in which it appears; consult the Table ofContents to find the appropriate chapter.

3. Determine the approximate latitude and longitude of thefeature from the maps in Figures 1.2 and 1.3. These coor-dinates can be used with the chart in the beginning of therelevant chapter to narrow the search for the correspond-ing photo.

4. Once the photo or photos that cover the area of interest arelocated, annotations will identify the name of the feature (ifit has a formal name) and the names of nearby features.

5. The notes on the page or pages describe something of theprocesses that took place to form the feature or itssurroundings.

6. The reference section refers to more detailed descriptionsin the literature for many of the photos.

The process described above can be followed in reverse. Ifan observer is interested in a feature found by browsing thebook, the latitude and longitude on the annotated photo canbe used to locate the feature relative to larger features on themaps of Figures 1.2 to 1.4. Then an observer can feature-walka telescopic field of view to the appropriate part of the Moon,just as one star-walks a field of view from one star group toanother to bring dim deep-sky objects into sight.

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Of course, these are only examples of ways this atlas can beuseful. The overview chapters and the introductions to theregional chapters can be read as a book summarizing thelargest features on the Moon and their relationships. Anotherway to use the atlas is to browse it. The notes need not be readsequentially. The atlas can also be used as a reference book.The feature index in the CD lists near side features with IAUnames and directs the reader to a relevant page. The SourceNotes section of the enclosed CD often identifies discussion offeatures in books of comprehensive coverage of the Moon,which refer in turn to additional research publications.

1.3. Large-Scale MapsFigure 1.1 is the full Moon, photographed from Earth. A fewoutstanding features are identified as an aid to orientationwhen looking at the Moon. The dark maria (low-lying areasflooded by lava) form the patterns variously known as theman in the Moon, the rabbit, and so on.

The map in Figure 1.2 is based on data from theClementine spacecraft. Clementine scanned the Moon from apolar orbit whose plane was aligned with the sun, so that thelunar surface shows its inherent brightness (called albedo),

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Figure 1.1. These regions of the Moon establish the scope of the corresponding chapters of this atlas. The base photo is from the Consolidated Lunar Atlas(LPI Web site).

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as it appears from Earth when the Moon is full. This mapshows features of the eastern and western limbs more clearlythan they can be seen from Earth.

Figures 1.3 and 1.4 are polar projections, mosaics ofClementine scans of the polar regions. Clementine’s bright-

ness sensor continued to look almost directly down at thesurface as the spacecraft passed nearly over the poles, butthese maps show the topography of the features rather thanthe albedo because the sun is always low near the poles.Under such low illumination, crater walls throw shadows.

90 W 60 W

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Mare Imbrium

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30 W 30 E 60 E 90 E0 E/W

Lunar Longitude

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Figure 1.2. Map of the near side of the Moon, based on Clementine brightness data (NRL Web site). Region names are the same as in Figure 1.1; the north-south regional boundaries are curved to follow the Lunar Orbiter 4 photos, planned for uniformity of the sun angle. Mare Orientale and the features on theeastern limb are visible from Earth only at times of favorable libration and then are much foreshortened. Note that features in the polar regions are stretchedhorizontally in this Mercator projection.

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Figure 1.4. South Polar Region; near side is at top. This circumpolar projection is based on Clementine brightness data (USGS Web site). The boundary ofthe South Polar Region (not shown) is at 55° south latitude.

Figure 1.3. North Polar Region; near side is at bottom. This circumpolar projection is based on Clementine brightness data (USGS Web site). The boundaryof the North Polar Region (not shown) is at 55° north latitude.

2.1. The MissionLunar Orbiter Mission 4 produced most of the photos in thisbook. This scientific mission was planned to systematicallycover the nearside of the Moon. Extensive 1-meter (1-m)photography had been taken of the candidate Lunar Orbiterlanding sites by missions 1 through 3, and the geologistswanted moderate-resolution photography (about 50 m) of somany large features on the nearside that a systematic surveymission was appropriate.

2.2. Mission DesignThe layout of exposures from orbit depends on many aspectsof the mission design. The spacecraft was placed in a high-in-clination (nearly polar) orbit to provide full coverage of thenearside of the Moon. The orbit was such that the incidenceangle of sunlight was about 20° (east to west; morning sun)throughout the photographic mission. While the 2-weekphotographic mission continued, the Moon revolved underthe orbit with approximately uniform sun angle from theeast limb to the west limb, presenting a new surface underthe spacecraft at each orbital pass. The period of the orbit,the altitude of the spacecraft, and the width of the high-resolution image were coordinated so that high-resolutionimages taken on successive orbits overlapped by about 10%at the lunar equator, with more overlap at high latitudes.Successive high-resolution photographs taken on the sameorbit were timed to overlap between about 10% as well. Theoverlap of photos avoids gaps in coverage, assists the con-struction of mosaics, and provides partial stereo coverage.

Most of the photos were taken vertically, except for thosenear the poles, where this could not be done because of thenature of the chosen orbit. The vertical photography mini-mizes foreshortening of the features to aid interpretation ofthe images.

Although all five of the Lunar Orbiters successfully pro-vided extensive new photographic coverage, there were oftenproblems, and Mission 4 was no exception. In this case, theproblem involved erratic operation of the thermal door, alens cap intended to protect the cameras from the cold ofdeep space when they were not actually making an exposure.Early in the mission, the optics chilled to the dew point ofthe moisture within the cameras and became fogged. The

Boeing operations team and the science team designed awork-around. The thermal door was left open, but the space-craft was oriented toward the sunlit part of the Moon so thatthe optics would be kept warm as much as possible.

Many photos of the eastern nearside were lost while theproblem was analyzed and resolved, but additional expo-sures were made at the end of the mission to replace most ofthe missed coverage. These photos were taken on the “backside” of the orbit, with the spacecraft near apolune. As a con-sequence they are at lower resolution than the other photosand lighting is reversed, coming from west to east.

A schematic of the layout of the high-resolution imagesacross the nearside of the Moon is shown in Table 2.1.

2.3. The CamerasThe Lunar Orbiter photography system consisted of twocameras, one with a short focal length and wide field of view(called the “medium-resolution camera”) and one with along focal length and a narrower field of view (called the“high-resolution camera”). The high-resolution field ofview was centered within the field of view of the medium-resolution camera and was more than three times longerthan it was wide.

The image motion compensation was provided by a feed-back loop based on a circular scan of part of the high-resolu-tion image. This mechanism, which had failed on LunarOrbiter Mission 1 but worked flawlessly on all the later mis-sions, moved the film platen in two dimensions to track theimage.

Six fiducial marks (“sawteeth”) for mapping were pro-vided at the edge of the field of view. These marks have beentrimmed from the images in this book.

2.4. The FilmThe negative film was a fine-grained low-contrast 70-millimeter (70-mm) black-and-white standard Kodakproduct. The fine grain assured low graininess at high resolu-tion. The low contrast (about 1 to 1) was selected to tolerateunknown variations in the brightness of the lunar surface athigh resolution. A gray scale, resolution charts, and reticulemarks (small crosses, barely visible on the images in this

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Chapter 2

Lunar Orbiter Mission 4

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book) were exposed on the negative to assist in reconstruc-tion and calibration of the images after scanning.

The film was developed in the spacecraft by the KodakBimat process. A second 70-mm film, its thick emulsion satu-rated with developing fluid, was pressed against the exposednegative by rollers. The two-film sandwich was stored in abuffer of rollers until development was complete and thenthey were separated.

Unfortunately, the Bimat process was susceptible to cer-tain flaws. Small bubbles sometimes interposed between thenegative and developer film, leaving various patterns on thenegative. Also, rollers sometimes left bars across the filmwhere the film was paused. These defects are easily distin-guished from lunar features but unfortunately degrade aminority of the images.

2.5. Scanning andReconstructionThe developed film was scanned by the available technologyof the time; charge-controlled devices (CCDs) were still wellin the future. Instead, a cathode ray tube (CRT) was used toprovide a single scan line. Of course, this scan line couldprovide only the equivalent of about 800 pixels because oflimitations on the phosphor grain and focus of the electronbeam. This short (about 4 mm) scan line was aligned withthe long dimension of the film. A mirror directed it acrossthe 70-mm width of the film. A photocell detected variationsin brightness as a measure of the density of the developednegative. After the width of the film was scanned, the filmwas advanced by a little less than the width of the scan line,providing overlap between scans to avoid gaps.

On the ground, the recorded signal was received at a DeepSpace Network (DSN) site in California, Spain, or Australia,operated by the Jet Propulsion Laboratory (JPL). A CRT inthe Kodak Ground Recording Equipment (GRE) transformedthe signal into an image on 35-mm film. A segment of thisfilm (called a framelet) represented a scan of the mirroracross the 70-mm film in the spacecraft. There were twoGREs, backed up by two Ampex video tape recorders (theoriginal rotating head recorders) at each DSN site.

Once the 35-mm framelets were developed, they weretrimmed by automatic machines and assembled on a lighttable. This was done at JPL (during the mission), LangleyResearch Center, and the Army Mapping Service. The assem-

bled framelets were limited to about 60 centimeters (cm), 24 inches, in length; this was sufficient to fully reconstructthe medium-resolution frames, but the long high-resolutionframes were reconstructed as a set of three subframes.Contact prints were made from these reconstructed framesand subframes; these are the primary records of the photos.Second-generation images at the same scale are stored atNASA Regional Planetary Image Facilities around the world.

The Army Mapping Service often used the tape recordersto adjust the contrast and brightness of the surface. Typicalimages are at a contrast of about 3 to 1 relative to the bright-ness variations of the lunar surface. This contrast exagger-ates the brightness variation of topography, compressing thevariations in the brightest and darkest parts of an image, butalso amplifies the inherent brightness variation of rays andejecta blankets from craters.

2.6. Scanning ArtifactsThe complex deconstruction and reconstruction processes,involving multiple electrical, mechanical, optical, photo-graphic, and manual processes, introduced several types ofscanning artifacts. Thin bright lines, leaks from the lighttable between framelets, appear in most reconstructedframes and subframes. Sometimes negative framelets wereassembled on the light tables, so these lines are dark on thepositive prints. Variations in sensitivity of the phosphors onthe two CRTs used in the process (one in the spacecraft andone on the ground) and possibly variations in the sensitivityof the rotating heads of the tape recorder cause systematicbrightness variations in the series of framelets. This effect,which is quite distracting, is sometimes called the “venetianblind effect” because it appears as if the image has beenprojected on a set of venetian blinds.

2.7. Cleaning the ImagesA computer program written by the author specifically forthis purpose has cleaned the photographs in this book.Appendix A, in the enclosed CD, describes this process indetail. As a result, residual scanning artifacts are only occa-sionally visible in the printed photos. However, artifactsassociated with the development process in the spacecraftremain.

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3.1. Origin of the MoonTo understand these photos, one must understand the Moon,its geography, and the factors that have influenced its nearside surface. The origin of the Moon was a matter of vigorousdebate until about 12 years after the last Apollo mission. In1984, after many years of analysis of the 300 kilograms (kg),800 pounds, of rocks and soil returned by Apollo and Lunamissions, a consensus was struck that has lasted for the sub-sequent 20 years. The following narrative retells this consen-sus origin story, without attempting to review the debate ofalternative theories. The curious reader is encouraged toreview the references.

As unlikely as it seems, another planet perhaps about thesize of Mars and formed in the general orbital vicinity ofMars had its orbit perturbed by some unknown event andstruck the early Earth a glancing blow. Just as a small carabsorbs much of the energy of an impact with a large truck,the smaller planet, known as Theia, was partly vaporized,partly melted, and largely pulverized and thrown into space.Some of Theia escaped from Earth or fell to Earth, but mostof it ended up in an orbit near Earth. Modeling suggests thatmuch of the core of Theia, relatively dense, was pulled intoEarth and joined Earth’s core.

The pulverized and molten orbital components in near-Earth orbit (perhaps about four Earth radii according to thecomputer simulations) coalesced. As a result, the resultingbody was heated by gravitational energy, supplemented byradioactive energy, and largely melted into a deep magmaocean. Part of Theia had become the Moon.

The strong tidal forces generated by the orbital proximityof these two bodies caused a loss of energy in the total systemand a transfer of angular momentum between them. TheMoon’s rotation relative to its revolution about Earthstopped, so that the near side of the Moon always faces Earth(synchronism). The Moon’s orbital radius increased, absorb-ing some of the angular momentum of the early Earth; thatchange slowed Earth’s rotation to its current 24-hour period.

Most of these events occurred within the first 500 millionyears after the Earth had itself coalesced and took place in arelatively short interval, perhaps 100 million years (the coa-lescence of the Moon could have taken place within weeksafter the impact). Of course, the chaotic impact would havethrown material into many orbits, some of which may havetaken very much longer to impact the Moon. The heavilycratered surface reflects the arrival of many such delayed im-

pactors as well as new arrivals from the solar system after theouter surface had cooled and become solid. The rate ofarrival of these later impactors is a matter of intense interest.There is some evidence of a quiet period followed after atime by a brief period of a high rate of arrival, sometimescalled the cataclysm to suggest a major chaotic event in theSolar System.

As a result of this history, our Moon is somewhat unusualin the solar system. It contains much the same chemical ele-ments as the other rocky planets, but its crust contains a dis-tinctly different quantitative distribution of those elements.The mineralogy is often familiar to geologists from theirterrestrial experience, even to the point of the relevance ofan extensive descriptive vocabulary. But the Moon is (to ourcurrent knowledge) unique in having experienced two dis-tinct melting phases, one when Theia was formed as a planetand one when the Moon was formed from a part of Theia’sdebris. Each melting phase resulted in differentiation of theminerals, as heavy material sank and light material rose in two different gravity fields and two different thermaldomains. A set of elements called KREEP that is concen-trated when massive quantities of material are melted andsolidified are unusually abundant in some maria. Eruptingmagma carried the doubly concentrated material to thesurface.

3.2. The Near Side Versus theFar SideThe synchronization of the Moon’s rotation with its revolu-tion in the intense early tidal environment established that thenear side would always face Earth and be the visible side(visible to humanity before the mid-twentieth century, that is).

Measurements of the Moon’s gravitational field have es-tablished that the depth of the crust is less on the near sidethan on the far side. This implies that, for a given size of im-pactor or strength of internal processes, penetration of thecrust is more likely on the near side.

3.3. Mare and HighlandsThe Moon exhibits significant differences between the nearside and near side. In particular, much more mare material is

Chapter 3

Overview of the Near Side of the Moon

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found on the near side. Mare material is the relatively darkmaterial visible on the face of the Moon, contrasting with themore reflective highlands. It is made of relatively heavy min-erals that have risen from the mantle of the Moon, below thecrust. How can we explain this paradox of the rise of heavymaterials through light materials? The answer lies in the de-crease of density that accompanies heating. The materialbecomes lighter than crust because it is hotter. When itbecomes exposed, it quickly cools and is locked in place bythe rigidity of a surface exposed to the cold of deep spacehalf the time. The association of most mare material withpositive gravity anomalies called mascons (an abbreviationof “mass concentrations”) also reveals their high density.Both remote sensing and analysis of lunar rock and soilsamples returned to Earth have established that the materialsof the maria are heavier than highland materials because oftheir higher proportion of iron and magnesium.

Historically, the distinction between mare materials and themore pristine highland materials (so called because they are infact higher than mare, but also resemble terrestrial highlandsin their relatively rugged topography) has been very impor-tant, because elementary observation distinguishes the dark,flat mare from the relatively bright, rugged, highlands.

3.4. BasinsAs understanding grew, it no longer appeared that maria arefundamental to the structure of the lunar surface. Rather, itseems that mare regions are secondary to the formation oflarge basins by impactors that are large enough to compro-mise the integrity of the lunar crust. Such basins allow heavy,dark minerals to rise through the fractured crust from thehotter upper mantle below the crust. The basin associatedwith a mare region can be much larger and has a much moreextensive effect on lunar topography. Typically, only the inte-rior of the depression formed by the basin impactor floods(or partly floods) with mare material. However, depositsejected from the basin can extend for a distance that is a mul-tiple of the crater radius. Such basin ejecta blankets cover orpartially cover much more area than the central depression.

Basins that have been flooded with lava to form a mare arenamed for the mare they contain (the Orientale Basin isnamed for Mare Orientale). Basins that lack mare fill arenamed for two craters that happen to be superposed on thebasin (the Schiller-Zucchius Basin).

Because basins are more fundamental than their includedmaria, this introductory section emphasizes basins as land-marks for the geography of the Moon.

3.5. Landmarks forGeographyStrictly speaking, perhaps we should say selenography orlunography (writing about the Moon) instead of geography(writing about the Earth), but the term geography seems tobe more evocative of what we mean. Geography is notgeology: it refers to landforms and their relation, withoutemphasis on the mineralogy or the formation process of thelandforms. It is difficult to grasp a good mental image of the

major features of the Moon in terms of their global distribu-tion and relationships. There is no equivalent of the organi-zation of terrestrial geography in terms of continents andoceans that are so useful in establishing a mental and visualimage of Earth.

This section introduces a high-level list of eight regions,centered on interesting, memorable focal points. They arechosen for broad distribution, to ensure roughly uniformcoverage of the lunar near side. Each region is sufficientlysmall to support photographic and other images with rea-sonable distortion. The proposed regions, and the latitudeand longitude of their focal points, are shown in Table 3.1.

Basins were chosen as many of the focal points becausethey are major modifiers of the surface geology, not onlythrough their central rings and maria but also through theirejecta blankets. Specific basins were chosen as much for uni-formity of spacing around the lunar globe as for size or inter-est. In addition to basins, the North and South Polar Regionswere included because of the special significance of the shad-owed craters in those regions and also because the photo-graphic quality is quite different.

3.6. Descriptions of LandmarkRegionsThe following sections summarize the characteristics andprominent features of each region. Only enough descriptionis included to differentiate the regions from each other; thesedescriptions are not intended to be comprehensive or todiscuss the geology or stratigraphy of the regions in detail.No attempt is made to establish precise boundaries betweenthe regions: that would be like attempting a precise boundarybetween the Atlantic and Arctic Oceans. These regions are

Region Latitude Longitude

Orientale Basin Region (includes Grimaldi Basin) 19° S 95° W

Humorum Basin Region (includes Nubium Basin) 24° S 39.5° W

Imbrium Basin Region (includes Oceanus Procellarum) 35° N 17° W

Nectaris Basin Region (includes Tranquillitatis and Fecunditatis Basins and nearby highlands) 16° S 34° E

Serenitatis Basin Region (includes the Crisium Basin and nearby highlands) 17.5° N 58.5° E

Eastern Basins Region (the Smythii Basin, the Humboldtianum Basin, the Australe Basin, and intervening highlands) 2° S 87° E

North Polar Region (North Pole) 90° N NA

South Polar Region (South Pole) 90° S NA

Table 3.1. Landmarks for the regions of the Moon and their coordinates.Landmarks are in bold print. Note that the center of the Orientale Basin isactually around the western limb; it is included because much of the basinand its ejecta are on the near side.

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sproposed to serve as a method to organize imagery, an alter-native to latitude and longitude, and no representation ismade that they are of fundamental geologic or cartographicsignificance.

Orientale Basin RegionThe Orientale Basin, with its central mare and multiple rings,has been called the archetype of basins because it is bothlarge and relatively recent. Consequently, its structure is veryclear. The region includes the smaller Grimaldi Basin andcraters Schickard and Bailly.

Humorum Basin RegionThe Humorum Basin region includes the Nubium Basin andcraters Pitatus and Tycho. This region is particularly inter-esting for understanding the interactions of different typesof features such as the manner in which mare floors en-counter crater rims and highlands. The Fra Mauro Peninsulais an example of such a feature.

Imbrium Basin RegionThe Imbrium Basin and its ejecta blanket dominate much ofthe near side. The region includes Oceanus Procellarum, andother neighboring maria: Vaporum, Serenitatis, and Frigoris.Craters in this region include Kepler, Copernicus, Archimedes,and Aristoteles. This entire region is rich in maria, ejectablankets, and rays of craters. It also has a number of features(such as Vallis Schroteri) that are associated with the floodingof the mare floors.

Nectaris Basin RegionThe northeastern part of the Nectaris region is rich in maria,including Fecunditatis and Tranquillitatis as well as MareNectaris. To the west and south, the region includes exten-sive highlands. To the west, parts of these highlands arecovered with ejecta from the Imbrium Basin.

Serenitatis Basin RegionThis region includes the Serenitatis and TranquillitatisBasins, the northern part of the Fecunditatis Basin, and thewestern part of the Crisium Basin. The region shows theinterplay of overlapping basins.

Eastern Basins RegionFrom Earth, this region covers the eastern limb (edge, as wesee it) of the Moon. It includes the eastern part of theCrisium Basin, the Australe Basin, the Smythii Basin, andMare Marginis.

North Polar RegionThe heavy shadowing in both polar regions obscures bothphotography and passive spectral measurements, especiallyfor the floors of basins and craters. The near side part of theregion and the North Pole itself are largely covered withejecta from the Imbrium Basin. Craters in this region includeNansen, Shackleton, and Anaxagoras. The region includesthe Humboldtianum Basin.

South Polar RegionThe South Polar Region is dominated by the rim of the SouthPole–Aiken Basin and several smaller basins such as

Schrodinger, Planck, and Bailly. Permanently shadowedcrater floors in this region (as well as in the North PolarRegion) are believed to harbor deposits of hydrogen or waterice. Permanently sunlit crater rims nearby are proposed assites for solar power.

3.7. The Ages of the LunarFeaturesAn interesting attribute of a lunar feature is the time it wasformed. The ages of different features on the Moon are in-ferred from several sources.

Estimating AgesThe most precise ages are determined from measurement of isotope ratios in our precious rock samples; association ofthe samples with specific features establishes their time offormation.

When rock samples are unavailable, geologists resort toless precise measures. For example, sharply defined fea-tures are inferred to be recent because meteorite bombard-ment softens the edges of features by a process calledmass-wasting. Also, counts of crater densities can be used to estimate the time a surface has been exposed tobombardment.

Very often, even though absolute time cannot be deter-mined, the sequence of formation can be determined. Forexample, ejecta from a basin may overlay a crater or lavafrom a mare may flow into a crater. Such layering and thebranch of geology that studies it are called stratigraphy.

Named Age RangesSystematic study of stratigraphy, together with other clues,establishes a chain of evidence that leads to relative ages andestimated age ranges of most of the features of the Moon.These age ranges are named for associated archetypefeatures. In order from the oldest to the youngest, theranges are the Pre-Nectarian, Nectarian, Early Imbrian, LateImbrian, Eratosthenian, and Copernican Periods or Epochs.Geologists use the term “epoch” as a subdivision of a period.The Early Imbrian and the Late Imbrian Epochs are subdivi-sions of the Imbrian Period. The boundary between the Pre-Nectarian and Nectarian Periods is the time of the impactthat produced the Nectaris Basin. The Nectarian Period endswith the event that produced the Imbrium Basin. The EarlyImbrian Epoch spans the time between the Imbrium andOrientale events.

Large basin-forming events are used to divide these timeperiods because such events spread their deposits so very far,as much as halfway around the Moon. This method allows usto relate many other features to large basin events by analyz-ing interactions with the widespread deposits. BecauseOrientale is the last big basin, however, the younger ageranges are based on large craters. The Eratosthenian Periodis next, and then the Copernican Period (this interval is openended; we live in the Copernican Period). These last twoperiods are not distinguished by bounding events, but on thedegree of degradation of craters and their ejecta (especiallythe fading of rays) as they are exposed to further impacts andto the solar wind.

4.1. Grouping by LandmarkRegionsEach chapter that follows displays images of a particularlandmark region. A few medium-resolution frames areshown for each region to provide an overview. Only a few ofthe medium-resolution photos are presented because theyhave a high degree of overlap. The high-resolution photosare selected in rectangular blocks so that a reasonable degreeof organization is imposed. The relation of the photos andtheir assignment to regions is shown in a table in eachchapter.

4.2. Order: West to East andSouth to NorthThe regions are presented from the west limb around thenearside to the east limb; that is because Orientale, thenewest and clearest basin and Imbrium, the largest nearsidebasin, are both toward the west and are should be viewedbefore the other regions. Keep in mind, however, that themission and the rising sun move from east to west. To mini-mize confusion, the photos covering a particular longituderange are presented from south to north (in the order mostof the photos were taken, and in order of the numbering con-vention for those photos). A few of the photos in the EasternBasin Region were taken in reverse of the usual orbital direc-tion, to compensate at the end of the mission for photos lostat the beginning of the mission.

4.3. Clean and AnnotatedImagesOne page is provided for each high-resolution subframe orframe. The cleaned image is shown on the right side of eachpage and an overlay with the major features of the imagelabeled is on the left. A title line shows the photo number,lighting conditions, and spacecraft altitude at the time of theexposure. Latitude and longitude marks and a scale bar areshown in the annotated overlay. The scale bar is derivedfrom the size of prominent surface features, as listed on the

USGS Web site. Except for the apostrophe, diacritical marksin feature names have been omitted in both photos and textbecause they are not supported in the software used to anno-tate the photos. A list of names with diacritical marks asguides to pronunciation is in the enclosed CD.

4.4. High-Resolution Framesand SubframesIn most cases, subframes (designated H1, H2, and H3) aredisplayed. In some cases, the three subframes are reassem-bled as a full high-resolution frame (designated H). This isdone either to show the relationship of the features acrossthe full exposure or because the features displayed aredeemed to be of relatively little interest, usually because ofsimilarity to their surroundings. All subframes are presentedat full detail in the enclosed CDs.

4.5. Discussion NotesThe photo pages contain notes that point out and discuss rel-evant aspects of the features and their relationships. Thesenotes draw on an extensive lunar literature to include aspectsof the stratigraphy, geology, and possible formation andmodification processes of the features.

4.6. Enclosed Compact Disc(CD)The enclosed CD contains:

● All high-resolution subframes from Lunar OrbiterMission 4 (JPEG files)

● All medium-resolution frames from Lunar OrbiterMission 4 (JPEG files)

● An index of nearside features whose names are recognizedby the International Astronomical Union (IAU)

● A description of the process used to clean up scanningartifacts

● Source notes related to individual photos

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The feature index includes all the near side features in themaster IAU list maintained by the USGS that are larger than6 km. Several smaller features and some far side featuresnear the eastern limb, the western limb, the North Pole, or

the South Pole are also included. Each of the features listedin the index can be found in the annotated photo (and thephoto number) on the indicated page.

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5.1. OverviewOrientale, the Archetype Multi-RingedBasinFigure 5.1 shows the spectacular Orientale Basin, thenewest large basin on the Moon. It is often called the ar-chetype of basins because it reveals the structure of basinsso clearly. Like typical large basins, it is multi-ringed; thatis, there are a number of concentric rings both inside andoutside of its major raised rim. Mare surfaces have beenformed from lava seeping up from below its central floor.Additional lava has seeped up into the low troughs betweenthe external rings.

Although the Orientale Basin has many features incommon with all basins, it must be considered that there aresignificant differences between basins as well. The detailedstructure of a basin depends on the nature of the target mate-rial. Orientale has formed in an area of thick, somewhatuniform crust. Although there are no major basins in itsimmediate vicinity, large craters have been identified thatinfluenced its detailed structure.

Orientale Basin and its included Mare Orientale arelocated on the western edge of the Moon, the edge that risesand sets last. Terrestrial astronomers glimpse its easternrings as the libration of the Moon turns that edge a bittoward us. Spacecraft Zond 3 photographed it in 1965 at es-sentially Earth-based resolution. However, the Lunar Orbiter4 coverage showed the magnificence of its structure at amuch higher resolution.

These photos created a major paradigm shift in minds ofgeologists who had been debating whether volcanism orimpacts dominated the lunar surface. This newest basin hada fresh ejecta blanket, revealed in detail by the high-resolutionphotos. The unavoidable conclusion was that many geologicunits whose origins were debated were in fact formed byejecta, not only from Orientale but also from larger, olderbasins such as Imbrium. This insight was confirmed andstrengthened by the pervasive discovery of impact breccia inthe rocks returned by Apollo missions. Such rocks areformed by the hypervelocity shock of impacts welding preex-isting rock fragments from diverse sources into larger rocks.They show a diverse set of shock effects, from changes of crystalline structure to partial or complete melting(Wilhelms, 1987).

A remarkable property of multi-ringed basins is the regu-larity of the radii of the concentric rings. Such rings arefound not only on the Moon (where there is evidence ofabout 60 multi-ringed basins), but also on Earth, Mercury,Mars, the Jupiter moons Ganymede and Callisto, and the Saturn moons Tethys and Rhea (Spudis, 1993). Measure-ments of the rings of basins on all these bodies fit a specificrelationship; successive rings, both internal and external tothe topographic rim (the ring of highest elevation also calledthe main ring), have radii in the ratio of the square root of 2.

Chapter 5

Orientale Basin Region

Figure 5.1. LO4-187M. The Orientale Basin is the archetype of multi-ringed basins. The lava flow of Mare Orientale is in the dark center of theconcentric rings. The dark mare surface to the upper right is OceanusProcellarum, the largest deposit of mare on the Moon. The small dark circu-lar feature is a mare deposit on the floor of the 440-km Grimaldi Basin. Thebright rays in the upper right corner of the photo radiate from Glushko, asmall crater near Oceanus Procellarum, not from Orientale.

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This relationship, equivalent to the doubling of the area ofeach successive ring, is very regular, but has no consensustheoretical basis at this time.

Crater Morphology as a Function ofSizeSmall impact craters do not have such concentric rings. Thesmallest craters have a transient cavity that is nearly hemi-spherical. The transient cavity is the zone of target materialthat was melted and pulverized by the hypervelocity impact.Some of this material is ejected, with most of it landingwithin one radius of the transient cavity from the rim of the transient cavity. This rim is a single topographic ring.Medium-sized craters have a distinctive central peak; thefocused sound wave rebounding from the mass of pulverizedand compressed material has lifted material nearly vertically,and it forms a mountain in the center of the crater. As the di-ameters of lunar craters exceed about 300 km (200 miles), thecentral peak breaks up into one or more internal rings, andexternal rings form as well. It is these very large craters thatwe call multi-ringed basins, or basins for short. The bottomsof large craters may penetrate near or through the boundarybetween the crust and the mantle.

Surroundings of the Orientale BasinTo the north and west, the ejecta blanket from Orientale hasbeen deposited on highlands. To the northeast, the ejecta fellon the surface later covered by the mare material of OceanusProcellarum. To the east and south lie highlands interruptedby other, smaller basins: Grimaldi and Humorum. The flankof Grimaldi shows fine striations radial to Orientale, so itmust have formed earlier. Similarly, the Humorum Basinpredates Orientale.

Figure 5.2 shows a mosaic of the eastern sector of theOrientale Basin Region, illustrating the structure of its rings.

5.2. High-Resolution ImagesTable 5.1 shows the high-resolution images of the OrientaleBasin region in schematic form.

The following pages show the high-resolution subframesfrom south to north and west to east; that is, they are in theorder LO4-194H, LO4-195H1, LO4-195H2, LO4-195H3, LO4-186H1 . . . LO4-161H3. Note that the photos taken on a givenorbit are presented in order; both frame and subframenumbers increase in the same order as the pages of thisbook. However, in moving from west to east to a new orbitalsequence, the numbers decrease.

LO4-194H has been assembled as a complete frame. Itshows the range of Orientale ejecta from the topographic rimto one radius away from that rim. In addition, it illustrateshow subframes are contiguous parts of high-resolutionframes. Similarly, LO4-169H and LO4-161H are displayed asfull frames.

Subframes LO4-180H1 and LO4-167H1 are not printed inthis chapter because they are redundant with the subframesto their east and west and show no additional features. Thebase photos are included in the enclosed CD.

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s Figure 5.2. Mosaic of Lunar Orbiter 4 high-resolution photos of theOrientale Basin, from the central mare at the left out past the concentricrings to the right. Dark mare material is found not only in the central part ofthe basin, but also in the troughs between the rings. Note the striations inthe ejecta blanket radiating from the central portion of the basin. They havea stronger appearance to the northeast and southeast rather than directlytoward the east. Because of the direction of solar illumination, ridges ori-ented in the east-west direction do not cast shadows. The smaller GrimaldiBasin in the upper right of the mosaic shows both a topographic ring thathas contained most of the mare lava and a lower outer ring.

Latitude Range Photo Number

27 N–56 N 189 183 175 170 163 158

0–27 N 188 182 174 169 162 157

0–27 S 195 187 181 173 168 161 156

27 S–56 S 194 186 180 172 167 160 155

56 S–90 S 179 166 154

Longitude 95 W 89 W 82 W 76 W 68 W 62 W 56 Wat Equator

Table 5.1. The cells shown in white represent the high-resolution photosof the Orientale Basin Region (LO4-XXX H1, -H2, and -H3, where XXX is thePhoto Number; LO4 means Lunar Orbiter Mission 4). The Imbrium BasinRegion is to the northeast, the Humorum Basin Region is to the east, and theSouth Polar Region is to the south. The far side is to the west. The nextnumber after LO4 is the exposure number, which increased as the missionprogressed from east to west.

LO4-194HSun Elevation: 16.10°Altitude: 3002.79 km

This full high-resolution frame showsthe inner Orientale Basin at the top.Montes Cordillera is the topographicring. Its scarp bounds the floor of thebasin. The arc of Montes Rook shownhere is the first inner ring of theOrientale Basin.

Striations show a heavy deposit ofejecta (the Hevelius Formation) fromthe inner Orientale Basin to the south.The character of the ejecta changesfrom the heavy, striated inner HeveliusFormation to the lighter, more uniformouter Hevelius Formation about 440 kmaway from the rim of the MontesCordillera ring (930 km in diameter).Graff, Catalan, and Baade have beencovered with a heavy deposit whileYakovin has received a lighter deposit.Several other craters in the 10- to 30-kmrange (probably secondaries fromOrientale) left deposits of fine ejectaoutside their rims.

The crater Hausen (out of the pictureto the southwest) has more recentlydeposited chains of small secondarycraters that can be seen on the floor of crater Pingre and outside its rim.Pingre may lie on the floor of an olderbasin called the Pingre-Hausen Basin.The large semicircular ridge east andnorth of Pingre is the boundary of thatbasin.

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r no

rth

of M

are

Ori

enta

le (

see

LO4-

195H

2).

The

Mau

nder

For

mat

ion

has

been

inte

rpre

ted

as th

e m

elt s

heet

of t

he b

asin

. The

frac

ture

sre

lieve

str

esse

s th

at c

ould

hav

e be

en a

ssoc

iate

d w

ith

cool

ing

of t

he m

elt

shee

t, se

ttlin

g of

und

erly

ing

pulv

eriz

ed m

ater

ial,

or fl

oodi

ng o

f th

e m

are.

Oth

er b

asin

s m

ay h

ave

had

sim

ilar

mel

t sh

eets

tha

t w

ere

com

plet

ely

hidd

en b

y a

late

r co

veri

ngof

mar

e la

va.

16

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

195H

1Su

n El

evat

ion:

14.

50°

Alt

itud

e: 2

721.

44 k

m

Mau

nder

was

obv

ious

ly f

orm

ed a

fter

the

mar

e flo

or h

adso

lidifi

ed. I

t has

a ty

pica

l pro

file

for

a la

rge

(55-

km)

prim

ary

crat

er,

wit

h a

wel

l-fo

rmed

cen

tral

pea

k, t

erra

ced

wal

ls,

anej

ecta

bla

nket

wit

h ra

dial

fur

row

s, a

nd a

fiel

d of

sec

onda

rycr

ater

s. T

he m

elt

shee

t of

the

Mau

nder

For

mat

ion

(nam

edaf

ter

the

crat

er)

appe

ars

to h

ave

part

ially

col

laps

ed a

t ei

ther

side

of t

he M

aund

er c

rate

r, p

ossi

bly

due

to th

e im

pact

sho

ck.

The

eje

cta

of s

ome

post

-mar

e cr

ater

s su

ch a

s Il

’in a

ppea

r to

have

flow

cha

ract

eris

tics

, as

if t

hey

impa

cted

whi

le t

he m

are

was

sti

ll se

mim

olte

n or

sti

ll ho

t en

ough

to

be m

elte

d by

the

impa

cts.

See

the

note

for

Kop

ff w

ith

phot

o LO

4-18

7H2.

LO4-

195H

2Su

n El

evat

ion:

14.

50°

Alt

itud

e: 2

721.

44 k

m

17

Ori

enta

leBa

sin R

egio

n

The

are

a in

thi

s ph

oto

show

s m

any

diff

eren

ces

in s

truc

ture

and

text

ure.

Com

pare

the

sm

ooth

mar

e la

va o

f La

cus

Ver

isw

ith

the

rugg

ed c

liffs

of t

he in

ner

ridg

e of

Mon

tes

Roo

k an

dth

e kn

obby

, fla

t M

onte

s R

ook

Form

atio

n be

twee

n M

onte

sR

ook

and

Mon

tes

Cor

dille

ra. N

ote

the

stee

p sc

arp

of th

e ri

mof

Mon

tes

Cor

dille

ra a

nd t

he t

hick

, ro

py n

atur

e of

the

in

ner

Hev

eliu

s Fo

rmat

ion

of b

asin

eje

cta

beyo

nd M

onte

sC

ordi

llera

. C

rate

rs K

ram

arov

and

Cou

der,

abo

ut t

he s

ame

size

and

age

(ju

dgin

g by

rim

sha

rpne

ss),

sho

w a

n in

tere

stin

gco

ntra

st i

n st

ruct

ure.

Kra

mar

ov,

impa

ctin

g th

e H

evel

ius

Form

atio

n, h

as t

hrow

n m

ore

ejec

ta a

nd p

art

of i

ts w

all

has

colla

psed

. C

oude

r, i

mpa

ctin

g th

e R

ook

Form

atio

n, h

as a

smal

ler

ejec

ta b

lank

et a

nd s

moo

th w

all.

Its

oval

sha

pe i

ndi-

cate

s a

low

impa

ct a

ngle

.

LO4-

195H

3Su

n El

evat

ion:

14.

50°

Alt

itud

e: 2

721.

44 k

m

18

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s ar

ea

has

been

co

vere

d w

ith

the

oute

r H

evel

ius

Form

atio

n, e

ject

a fr

om O

rien

tale

, as

can

be

seen

fro

m t

hech

ain

of O

rien

tale

sec

onda

ry c

rate

rs d

own

thro

ugh

the

cent

er o

f th

e ph

oto.

On

the

righ

t is

a s

erie

s of

con

cent

ric-

wal

led

crat

ers

that

may

hav

e fo

rmed

as

they

enc

ount

ered

afir

m la

yer

bene

ath

a so

fter

laye

r of

reg

olit

h, t

he e

ject

a fr

omO

rien

tale

and

oth

er b

asin

s. S

imul

atio

ns s

ugge

st t

hat

such

stru

ctur

es fo

rm w

hen

the

appa

rent

cra

ter

diam

eter

is 8

to 1

0ti

mes

the

dept

h of

the

rego

lith.

Yak

ovki

n ap

pear

s to

hav

e re

-ce

ived

a r

elat

ivel

y lig

ht c

oati

ng o

f ej

ecta

. It

als

o m

ay h

ave

been

floo

ded

wit

h la

va a

fter

the

eje

cta

had

been

dep

osit

ed;

its

surf

ace

seem

s ve

ry s

moo

th a

nd fr

ee o

f sm

all c

rate

rs.

LO4-

186H

1Su

n El

evat

ion:

15.

60°

Alt

itud

e: 3

005.

57 k

m

19

Ori

enta

leBa

sin R

egio

n

Thi

s ar

ea, l

ike

muc

h of

the

Moo

n, h

as b

een

repe

ated

ly o

ver-

laid

wit

h ba

sin

ejec

ta. T

he la

rges

t sca

le li

near

feat

ures

rad

iate

from

the

Ori

enta

le B

asin

, ju

st t

o th

e no

rthw

est.

How

ever

,th

ere

are

smal

ler-

scal

e lin

ear

feat

ures

run

ning

fro

m s

outh

-w

est

to n

orth

east

fro

m t

he o

lder

Men

del-

Ryd

berg

Bas

in t

oth

e so

uthw

est.

Baa

de, f

orm

ed in

a th

ick

ejec

ta b

lank

et, h

as a

wea

k ce

ntra

l pe

ak.

Val

lis

Bou

vard

and

Val

lis

Baa

de a

rech

ains

of

seco

ndar

y cr

ater

s an

d ot

her

ejec

ta f

rom

Ori

enta

leth

at p

low

ed t

hese

val

leys

in

low

-ang

le i

mpa

cts.

Sim

ilar

valle

ys a

ppea

r ar

ound

the

Imbr

ium

and

Nec

tari

s ba

sins

.

LO4-

186H

2Su

n El

evat

ion:

15.

60°

Alt

itud

e: 3

005.

57 k

m

20

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Mon

tes

Cor

dille

ra i

s th

e to

pogr

aphi

c (h

ighe

st)

rim

of

the

Ori

enta

le B

asin

. The

out

er r

ange

of M

onte

s R

ook

is th

e ne

xtm

ount

aino

us a

rea

tow

ard

the

cent

er o

f th

is m

ulti

-rin

ged

basi

n. B

etw

een

Mon

tes

Cor

dille

ra a

nd M

onte

s R

ook

is

the

flat

knob

by p

lain

of

the

Mon

tes

Roo

k Fo

rmat

ion.

The

bott

om o

f the

trou

gh b

etw

een

the

two

ring

s of

Mon

tes

Roo

kis

eve

n lo

wer

tha

n th

e M

onte

s R

ook

Form

atio

n. C

rate

rsPe

ttit

, Nic

hols

on, W

righ

t, an

d Sh

aler

sho

w s

lum

ping

of t

heir

crat

er w

alls

, sug

gest

ing

that

the

y m

ay h

ave

impa

cted

a lo

w-

stre

ngth

mat

eria

l, a

cont

rast

to

crat

ers

impa

ctin

g th

e m

elt

shee

t of

the

Mau

nder

For

mat

ion

wit

hin

the

Mon

tes

Roo

kri

ngs.

LO4-

186H

3Su

n El

evat

ion:

15.

60°

Alt

itud

e: 3

005.

57 k

m

21

Ori

enta

leBa

sin R

egio

n

Bet

wee

n th

e ou

ter

and

inne

r ra

nges

of

Mon

tes

Roo

k is

ava

lley

of c

haot

ic m

ater

ial.

Thi

s hu

mm

ocky

zon

e co

uld

be a

mix

of r

ubbl

e an

d m

elte

d m

ater

ial f

rom

the

impa

ct, t

oget

her

wit

h ex

trus

ions

fro

m b

elow

. Ex

tens

ive

frac

turi

ng i

n th

iszo

ne, a

ppea

ring

at

the

surf

ace

as R

imae

Pet

tit

(LO

4-19

5H1)

,m

ay i

ndic

ate

cont

ract

ion

or s

ubsi

denc

e re

late

d to

coo

ling

and

othe

r ad

just

men

ts a

fter

the

impa

ct. P

etti

t and

Nic

hols

onap

pear

to

have

impa

cted

the

out

er M

onte

s R

ook

ridg

e w

hile

it w

as n

ewly

form

ed; t

heir

eje

cta

seem

s to

hav

e be

en m

olte

nan

d th

eir

wal

ls e

ithe

r sl

umpe

d to

the

ir fl

oors

or

addi

tion

alm

ater

ial l

ande

d in

them

. The

y m

ay b

e se

cond

arie

s ex

cava

ted

by e

ject

a th

row

n in

a h

igh

traj

ecto

ry fr

om th

e O

rien

tale

eve

ntit

self.

LO4-

187H

1Su

n El

evat

ion:

13.

90°

Alt

itud

e: 2

722.

79 k

m

22

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

187H

2Su

n El

evat

ion:

13.

90°

Alt

itud

e: 2

722.

79 k

m

23

Ori

enta

leBa

sin R

egio

n

Lacu

s V

eris

is

a sm

all

mar

e ar

ea f

orm

ed i

n th

e tr

ough

betw

een

the

two

ridg

es o

f Mon

tes

Roo

k. S

tres

s fr

actu

res

cir-

cum

fere

ntia

l to

the

basi

n ri

m a

long

the

edg

e of

Lac

us V

eris

.O

ther

fra

ctur

es r

un a

cros

s an

d ne

ar i

t. T

hese

fra

ctur

e lin

esdi

sapp

ear

as th

ey e

ncou

nter

mar

e m

ater

ial,

whi

ch m

ust h

ave

flood

ed a

fter

str

ess

was

rel

ease

d by

frac

turi

ng. T

his

frac

ture

dte

rrai

n, th

e M

aund

er F

orm

atio

n, is

thou

ght b

y m

ost a

naly

sts

to b

e im

pact

mel

t. C

rate

r K

opff

, un

like

Mau

nder

(se

e LO

-195

H2)

, has

a s

hallo

w, fl

at fl

oor,

a s

moo

th r

im w

itho

utte

rrac

es, a

nd n

o ce

ntra

l pe

ak. I

ts e

ject

a se

ems

mol

ten,

lik

eth

at o

f Pe

ttit

and

Nic

hols

on. K

opf

may

als

o be

a s

econ

dary

that

im

pact

ed a

sti

ll-m

olte

n m

elt

shee

t an

d w

as fl

oode

d by

mar

e m

uch

late

r.

LO4-

187H

3Su

n El

evat

ion:

13.

90°

Alt

itud

e: 2

722.

79 k

m

24

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s ar

ea n

orth

of

the

inne

r ba

sin

show

s th

e kn

obby

ter

rain

betw

een

Mon

tes

Roo

k an

d M

onte

s C

ordi

llera

and

the

stri

ated

eje

cta

blan

ket

beyo

nd M

onte

s C

ordi

llera

. M

onte

sC

ordi

llera

typi

cally

sho

ws

a sc

arp

(clif

f) a

t its

inne

r ed

ge. T

hesu

btle

cir

cula

r fe

atur

e ju

st n

orth

of

the

crat

er C

oude

rap

pear

s to

be

a pr

eexi

stin

g cr

ater

tha

t w

as c

over

ed b

y th

eej

ecta

from

Ori

enta

le.

Thi

s ar

ea, c

over

ed b

y th

e st

riat

ed in

ner

Hev

eliu

s Fo

rmat

ion

of O

rien

tale

eje

cta,

has

no

feat

ure

wit

h an

IA

U n

ame.

The

radi

al s

tria

tion

s ar

e em

phas

ized

by

the

righ

t-to

-lef

t su

ndi

rect

ion.

An

80-k

m c

rate

r on

the

upp

er r

ight

sid

e of

the

phot

o ha

s be

en s

ubm

erge

d by

the

eje

cta,

but

see

ms

to h

ave

focu

sed

the

flow

line

s at

its

far

edge

.

LO4-

188H

1Su

n El

evat

ion:

14.

50°

Alt

itud

e: 2

675.

46 k

m

25

Ori

enta

leBa

sin R

egio

n

Eins

tein

, Sun

dman

, and

Boh

r ar

e pr

eexi

stin

g cr

ater

s co

vere

dby

Ori

enta

le d

epos

its,

inc

ludi

ng fi

elds

of

seco

ndar

ies.

The

seco

ndar

y ch

ain

of V

allis

Boh

r an

d se

cond

arie

s on

the

floo

rof

Ein

stei

n ar

e ty

pica

l of

the

oute

r H

evel

ius

Form

atio

n. T

hetr

ansi

tion

fro

m t

he i

nner

For

mat

ion

is n

ear

the

bott

om o

fth

is p

ictu

re, a

bout

one

rad

ius

away

from

Mon

tes

Cor

dille

ra.

The

80-

km c

rate

r in

the

low

er r

ight

cor

ner

is fi

ssur

ed, s

ug-

gest

ing

that

the

ejec

ta th

ere

may

hav

e be

en m

olte

n an

d th

encr

acke

d as

it c

oole

d. V

ario

us lo

bate

flow

pat

tern

s ca

n be

see

nhe

re. T

he 1

0-km

cra

ter

abou

t 70

km s

outh

east

of S

undm

an is

in a

ver

y da

rk, l

ow-l

ying

are

a, a

nd th

e cr

ater

has

a r

are

dark

ray

patt

ern

in C

lem

enti

ne a

lbed

o da

ta.

LO4-

188H

2Su

n El

evat

ion:

14.

50°

Alt

itud

e: 2

675.

46 k

m

26

Luna

r O

rbiter

Photo

gra

phic

Atla

s

The

Ori

enta

le e

ject

a is

bec

omin

g th

in h

ere,

in

an a

rea

wel

lno

rth

of th

e ba

sin

floor

. Mar

e su

rfac

es o

n th

e ri

ght a

re a

t the

edge

of

Oce

anus

Pro

cella

rum

. C

rate

rs V

oskr

esen

skiy

and

Bar

tels

app

ear

to h

ave

been

floo

ded,

as

is c

omm

on n

ear

the

edge

of

a la

rge

mar

e. A

pos

sibl

e se

cond

ary

from

Ori

enta

leha

s hi

t the

nor

thea

st c

rate

r w

all o

f Bar

tels

and

left

deb

ris

onit

s flo

or. T

he s

catt

erin

g of

cra

ters

abo

ut 1

0 km

in

diam

eter

,w

ith

sim

ilar

fre

sh a

ppea

ranc

es,

are

prob

ably

sec

onda

ries

from

Ori

enta

le. T

he fl

oor

of M

osel

ey h

as a

com

plex

app

ear-

ance

, as

if a

lava

flow

ent

ered

it fr

om th

e no

rth.

LO4-

188H

3Su

n El

evat

ion:

14.

50°

Alt

itud

e: 2

675.

46 k

m

27

Ori

enta

leBa

sin R

egio

n

LO4-

180H

2Su

n El

evat

ion:

16.

10°

Alt

itud

e: 3

008.

99 k

m

28

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Like

Val

lis

Baa

de,

Val

lis

Ingh

iram

i an

d it

s bo

undi

ng

ridg

es h

ave

been

for

med

by

the

inne

r H

evel

ius

Form

atio

nej

ecte

d fr

om O

rien

tale

. Suc

h ej

ecta

als

o co

vere

d th

e cr

ater

Ingh

iram

i an

d a

sim

ilar

cra

ter

nort

hwes

t of

the

hea

d of

Val

lis

Ingh

iram

i. N

ote

the

21-k

m c

rate

r ne

ar t

hat

valle

yhe

ad.

Its

conc

entr

ic c

rate

r fo

rm (

a lit

tle

off

cent

er i

n th

isca

se)

sugg

ests

that

it h

as p

ulve

rize

d ab

out 2

km

of d

epos

ited

mat

eria

l fr

om t

he fl

oor

of t

he v

alle

y be

fore

enc

ount

erin

gm

ore

resi

stan

ce. S

hado

win

g on

the

val

ley

wal

l ind

icat

es t

hat

the

ridg

es r

ise

2 or

3 k

m a

bove

the

valle

y flo

or.

The

cra

ter

Kra

snov

and

the

unn

amed

45-

km c

rate

r ab

ove

itst

radd

le th

e ar

ea o

f the

sca

rp a

nd p

rovi

de c

lues

to it

s na

ture

.T

he u

nnam

ed c

rate

r is

kno

wn

to h

ave

form

ed b

efor

e or

in

an e

arly

pha

se o

f th

e O

rien

tale

seq

uenc

e of

eve

nts

beca

use

its

rim

has

bee

n ex

tens

ivel

y m

odifi

ed b

y ej

ecta

. Bec

ause

the

rim

of

Kra

snov

is

shar

p, i

t m

ust

have

for

med

aft

er t

heO

rien

tale

eve

nt o

r la

te i

n it

s se

quen

ce. T

he m

assi

ve d

epos

iton

the

floo

r of

the

unn

amed

cra

ter

sugg

ests

tha

t th

e ri

m o

fM

onte

s C

ordi

llera

, w

hose

sca

rp i

s of

sim

ilar

dep

th,

isco

vere

d w

ith

depo

site

d m

ater

ial.

A n

arro

w t

erra

ce o

n th

ein

ner

wal

l of K

rasn

ov m

ay in

dica

te e

ithe

r th

e le

vel o

f the

pre

-O

rien

tale

sur

face

or

an in

terf

ace

betw

een

succ

essi

ve la

yers

of

ejec

ta.

LO4-

180H

3Su

n El

evat

ion:

16.

10°

Alt

itud

e: 3

008.

99 k

m

29

Ori

enta

leBa

sin R

egio

n

The

inne

r ed

ge o

f Mon

tes

Cor

dille

ra h

as a

sha

rp s

carp

(st

eep

slop

e). S

uch

scar

ps m

ay b

e fo

rmed

by

exca

vati

on o

f th

e lo

wsi

de o

r by

lift

ing

of th

e hi

gh s

ide

(suc

h as

by

tilt

ing

a bl

ock)

.St

rong

str

iati

ons

appe

ar t

o cr

oss

the

valle

y be

twee

n M

onte

sR

ook,

red

uce

the

scar

p of

Mon

tes

Cor

dille

ra s

outh

of

Eich

stad

t, a

nd c

onti

nue

acro

ss M

onte

s C

ordi

llera

(se

e LO

4-17

2H1

for

the

cont

inua

tion

to th

e so

uthe

ast)

. The

se s

tri-

atio

ns a

re r

elat

ivel

y su

bdue

d in

the

val

ley

betw

een

the

two

mou

ntai

n ra

nges

. Thi

s su

gges

ts th

at th

e va

lley

floor

was

flui

d(e

ithe

r m

olte

n or

fine

ly p

ulve

rize

d) a

nd p

erha

ps s

tron

gly

shak

en b

y a

soni

c or

tec

toni

c w

ave

afte

r th

e ej

ecta

bla

nket

was

dep

osit

ed.

LO4-

181H

1Su

n El

evat

ion:

14.

80°

Alt

itud

e: 2

723.

98 k

m

30

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

181H

2Su

n El

evat

ion:

14.

80°

Alt

itud

e: 2

723.

98 k

m

31

Ori

enta

leBa

sin R

egio

n

Mar

e la

va fl

oode

d no

t on

ly M

are

Ori

enta

le i

n th

e ce

ntra

lin

ner

basi

n bu

t al

so L

acus

Ver

is i

n th

e tr

ough

bet

wee

n th

ein

ner

and

oute

r ri

dges

of

Mon

tes

Roo

k an

d La

cus

Aut

umni

in t

he v

alle

y flo

or b

etw

een

Mon

tes

Roo

k an

d M

onte

sC

ordi

llera

. Cra

ter

coun

ts in

dica

te t

hat

the

orde

r of

floo

ding

is f

rom

the

cen

ter

of t

he b

asin

(w

here

a m

asco

n in

dica

tes

apl

ume

of m

antle

mat

eria

l has

ris

en)

outw

ard.

Lac

us A

utum

niha

s be

en j

ust

part

ially

floo

ded.

Som

e st

riat

ions

and

sec

-on

dary

cra

ters

in L

acus

Aut

umni

may

be

ejec

ta f

rom

cra

ter

Schl

uter

, jus

t to

the

nort

h (s

ee L

O4-

181H

3).

Cra

ters

Sch

lute

r an

d H

artw

ig,

just

out

side

the

Mon

tes

Cor

dille

ra,

are

inte

rest

ing

exam

ples

of

the

effe

ct o

f ba

sin

ejec

ta (

Hev

eliu

s Fo

rmat

ion)

. Har

twig

was

bla

nket

ed b

y th

isej

ecta

, but

Sch

lute

r im

pact

ed a

fter

war

d. T

his

stra

tific

atio

n,pl

us t

he la

va fl

oodi

ng in

par

t of

the

floo

r of

Sch

lute

r, e

stab

-lis

hes

its

age

as L

ate

Imbr

ian.

LO4-

181H

3Su

n El

evat

ion:

14.

80°

Alt

itud

e: 2

723.

98 k

m

32

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

182H

1Su

n El

evat

ion:

16.

10°

Alt

itud

e: 2

674.

44 k

m

33

Ori

enta

leBa

sin R

egio

n

Thi

s ar

ea i

s do

min

ated

by

the

inne

r H

evel

ius

Form

atio

n of

Ori

enta

le e

ject

a. T

he t

wo

20-k

m c

rate

rs in

the

upp

er h

alf

ofth

e ph

oto

may

sho

w c

lues

abo

ut t

he c

onsi

sten

cy o

f th

isej

ecta

. T

he m

ater

ial

on t

heir

floo

rs s

eem

s to

hav

e be

enm

olte

n, b

ut w

ith

grea

ter

visc

osit

y th

an t

he m

are

lava

flow

s.T

he m

ater

ial

seem

s to

hav

e be

en f

ract

ured

, pe

rhap

s by

cool

ing

or b

y se

ttlin

g on

the

pre

exis

ting

top

ogra

phy

of t

hecr

ater

floo

rs. A

long

thin

str

ing

of s

econ

dary

cra

ters

run

ning

from

sou

th-s

outh

east

to

nort

h-no

rthw

est

acro

ss t

he l

ower

half

of t

he p

hoto

rad

iate

s fr

om c

rate

r Sc

hlut

er t

o th

e so

uth

(see

LO

4-18

1H3)

. LO

4-17

4H1

show

s m

uch

of th

e ar

ea o

n th

eri

ght

side

of t

his

phot

o w

itho

ut t

he d

evel

opm

ent

arti

fact

s in

this

exp

osur

e.

Thi

s re

gion

sho

ws

clus

ters

of

Ori

enta

le s

econ

dary

cra

ters

,so

me

stri

atio

n an

d se

cond

ary

chai

ns f

rom

the

cen

tral

Ori

enta

le B

asin

, and

som

e de

posi

ts th

at a

ppea

r to

hav

e be

enm

olte

n (w

ith

flow

edg

es).

The

se a

re t

ypic

al f

eatu

res

of t

heou

ter

Hev

eliu

s Fo

rmat

ion.

Cra

ters

Bal

boa,

Dal

ton,

Vas

co d

aG

ama,

and

the

unn

amed

50-

km c

rate

r so

uth

of V

asco

da

Gam

a al

l ha

ve f

ract

ures

in

floor

s. S

uch

shal

low

fra

ctur

edflo

ors

are

com

mon

(bu

t no

t un

iver

sal)

nea

r th

e bo

unda

ries

of O

cean

us P

roce

llaru

m, w

hich

can

be

seen

nea

r th

e up

per

righ

t cor

ner

of th

e ph

oto.

The

frac

turi

ng m

ay b

e du

e to

upl

ift

of th

e flo

ors.

LO4-

182H

2Su

n El

evat

ion:

16.

10°

Alt

itud

e: 2

674.

44 k

m

34

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Seve

ral s

ubm

erge

d cr

ater

s su

ch a

s St

ruve

can

be

seen

in th

isar

ea o

f wes

tern

Oce

anus

Pro

cella

rum

. The

dep

th o

f the

mar

ela

va c

an b

e ju

dged

by

the

esti

mat

ed d

epth

of fl

oode

d cr

ater

s.T

he o

uter

Hev

eliu

s Fo

rmat

ion

of O

rien

tale

eje

cta

is th

inni

nghe

re, a

s in

dica

ted

by th

e de

crea

sing

rat

e of

sec

onda

ry c

rate

rsto

the

nort

heas

t.

LO4-

182H

3Su

n El

evat

ion:

16.

10°

Alt

itud

e: 2

674.

44 k

m

35

Ori

enta

leBa

sin R

egio

n

36

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

172H

1Su

n El

evat

ion:

16.

30°

Alt

itud

e: 3

010.

71 k

m

Mol

ten

mat

eria

l ha

s flo

oded

cra

ters

War

gent

in,

Nas

myt

h,an

d Ph

ocyl

ides

to

form

pla

ins,

but

it is

not

dar

k lik

e ty

pica

lm

are

lava

. The

mat

eria

l has

flow

ed o

ut o

f gap

s in

the

sou

th-

ern

edge

of

War

gent

in. T

he m

elt

may

hav

e be

en t

hrow

n ou

tfr

om t

he i

nner

Ori

enta

le B

asin

. It

appe

ars

to h

ave

cove

red

som

e of

the

str

iate

d ej

ecta

; if

it w

ere

thro

wn

out

at a

hig

her

angl

e an

d a

low

er v

eloc

ity,

it

wou

ld h

ave

arri

ved

late

r th

anth

e m

ater

ial

that

for

med

the

str

iati

ons.

The

clu

ster

s of

crat

ers

in t

he r

ight

sid

e of

thi

s ph

oto

are

seco

ndar

ies

from

Ori

enta

le,

whi

ch m

ay h

ave

been

thr

own

at a

n ev

en h

ighe

ran

gle

than

the

mel

t.

To

the

sout

heas

t, th

e ej

ecta

fro

m O

rien

tale

mee

ts a

nd o

ver-

lies

earl

ier

ejec

ta f

rom

the

160

-km

cra

ter

Schi

ckar

d (L

O4-

167H

2),

crea

ting

a c

ross

-hat

ched

ter

rain

. T

he fl

oor

ofIn

ghir

ami i

s co

vere

d w

ith

ejec

ted

mat

eria

l tha

t ha

s pi

led

upin

the

sout

heas

t qua

dran

t.

LO4-

172H

2Su

n El

evat

ion:

16.

30°

Alt

itud

e: 3

010.

71 k

m

37

Ori

enta

leBa

sin R

egio

n

The

inn

er H

evel

ius

Form

atio

n gr

ades

fro

m t

he v

ery

deep

mat

eria

l th

at c

ompo

ses

Mon

tes

Cor

dille

ra t

o th

e no

rthw

est

to th

inne

r m

ater

ial t

o th

e so

uthe

ast.

In th

e th

inne

r re

gion

s of

the

ejec

ta b

lank

et,

the

pree

xist

ing

topo

grap

hy c

an b

egl

imps

ed. T

he 2

25-k

m c

rate

r La

gran

ge h

as b

een

near

ly o

blit

-er

ated

. The

Ori

enta

le e

ject

a se

ems

to h

ave

push

ed m

ater

ial

from

the

nor

thw

est

rim

of

Lagr

ange

ont

o th

e cr

ater

’s fl

oor.

The

re is

a g

ap in

the

Ori

enta

le e

ject

a on

par

t of

the

floo

r of

the

old

80-k

m c

rate

r in

the

low

er r

ight

han

d co

rner

of

the

phot

o.

38

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

172H

3Su

n El

evat

ion:

16.

30°

Alt

itud

e: 3

010.

71 k

m

The

re i

s an

int

eres

ting

int

erac

tion

her

e be

twee

n th

e ol

d 12

0-km

cra

ter

betw

een

Eich

stad

t and

Lam

arck

and

the

heav

yflo

w o

f O

rien

tale

eje

cta

that

has

obl

iter

ated

its

wes

tern

rim

and

thro

wn

the

mat

eria

l ont

o th

e w

este

rn h

alf

of t

he c

rate

rflo

or. W

hen

ejec

ta h

it th

e sm

all c

rate

r in

the

low

er r

ight

han

dco

rner

of

the

pict

ure,

it

pile

d up

aga

inst

the

eas

tern

wal

l,ne

arly

up

to th

e to

p of

the

rim

.

LO4-

173H

1Su

n El

evat

ion:

15.

40°

Alt

itud

e: 2

724.

03 k

m

39

Ori

enta

leBa

sin R

egio

n

The

wes

tern

rim

s of

cra

ter

Roc

ca a

nd t

wo

smal

ler

crat

ers

toth

e so

uth

have

par

tly s

hiel

ded

the

wes

tern

floo

rs fr

om e

ject

a,bu

t it

has

acc

umul

ated

on

the

east

ern

floor

s an

d ag

ains

t th

efa

r w

alls

to th

e ea

st.

LO4-

173H

2Su

n El

evat

ion:

15.

40°

Alt

itud

e: 2

724.

03 k

m

40

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Like

the

floor

of S

chlu

ter

to th

e w

est,

Ric

ciol

i’s fl

oor

is p

artl

yflo

oded

wit

h m

are

lava

. T

he p

erva

sive

ness

of

ejec

ta f

rom

Ori

enta

le i

n th

is r

egio

n es

tabl

ishe

s th

at t

he m

are

flood

ing

mus

t ha

ve f

ollo

wed

the

Ori

enta

le e

vent

. R

icci

oli

coul

d no

tha

ve s

urvi

ved

the

Gri

mal

di B

asin

eve

nt (

LO4-

168H

3),

soR

icci

oli

mus

t ha

ve f

ollo

wed

Gri

mal

di. T

he s

eque

nce

is t

hus

Gri

mal

di, R

icci

oli,

Ori

enta

le, a

nd m

are

flood

ing

of t

he fl

oor

of R

icci

oli.

Rim

ae R

icci

oli

are

part

of

a la

rger

pat

tern

of

linea

tion

s to

the

nor

th (

LO4-

174H

1) a

nd e

ast

(LO

4-16

8H3)

.Pl

ains

-for

min

g un

its

nort

h of

the

rim

of

Ric

ciol

i, th

e so

uth-

east

floo

r of

Ric

ciol

i, an

d ab

out 8

0 km

sou

th o

f the

sou

ther

nri

m o

f R

icci

oli

are

inte

rpre

ted

as m

olte

n or

sem

imol

ten

ejec

ta fr

om O

rien

tale

.

LO4-

173H

3Su

n El

evat

ion:

15.

40°

Alt

itud

e: 2

724.

03 k

m

41

Ori

enta

leBa

sin R

egio

n

Cra

ter

Hed

in a

ppea

rs t

o be

sim

ilar

in a

ge t

o R

icci

oli.

It h

asbe

en c

over

ed w

ith

Ori

enta

le e

ject

a. T

o th

e no

rthe

ast,

jus

tbe

yond

Hed

in, t

here

is a

dep

osit

wit

h a

scal

lope

d sc

arp

that

seem

s to

hav

e co

me

from

the

sou

thea

st,

prob

ably

fro

mG

rim

aldi

. The

se d

epos

its

exte

nd b

eyon

d H

edin

to

the

east

.In

the

low

er h

alf o

f thi

s ph

oto

is a

ref

eren

ce a

rea

for

illus

tra-

tion

of

the

inne

r H

evel

ius

Form

atio

n, w

ith

its

stro

nglin

eati

ons

and

thic

k de

posi

ts o

f O

rien

tale

eje

cta.

The

upp

erri

ght

part

of

the

phot

o sh

ows

the

seco

ndar

y cr

ater

s an

dth

inne

r de

posi

ts o

f the

out

er H

evel

ius

Form

atio

n.

LO4-

174H

1Su

n El

evat

ion:

15.

50°

Alt

itud

e: 2

673.

10 k

m

42

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Cle

men

tine

dat

a sh

ow G

lush

ko t

o be

the

sou

rce

of a

str

ong

ray

patt

ern,

inc

ludi

ng t

he l

ight

str

eaks

tha

t ca

n be

see

n ex

-te

ndin

g to

Car

danu

s an

d K

raff

t. G

lush

ko h

as im

pact

ed a

uni

tof

pla

ins-

form

ing

mel

t fr

om O

rien

tale

. C

rate

rs K

raff

t an

dC

arda

nus,

whi

ch a

re s

o si

mila

r in

siz

e an

d ap

pare

nt a

ge th

atth

ey m

ay h

ave

orig

inat

ed i

n a

twin

im

pact

, hav

e de

posi

ted

thei

r ej

ecta

on

an

ol

der

mar

e un

it

wit

hin

Oce

anus

Proc

ella

rum

. N

ewer

mar

e un

its

have

floo

ded

out

part

s of

thei

r fie

lds

of s

econ

dary

cra

ters

. T

he c

rate

r ch

ain

Cat

ena

Kra

fft i

s co

mpo

sed

of s

econ

dari

es fr

om c

rate

r K

raff

t.

LO4-

174H

2Su

n El

evat

ion:

15.

50°

Alt

itud

e: 2

673.

10 k

m

43

Ori

enta

leBa

sin R

egio

n

LO4-

174H

3Su

n El

evat

ion:

15.

50°

Alt

itud

e: 2

673.

10 k

m

44

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Cra

ters

Str

uve,

Edd

ingt

on, a

nd R

usse

ll ar

e ri

nged

pla

ins,

old

crat

ers

flood

ed b

y m

are

lava

wit

hin

Oce

anus

Pro

cella

rum

.T

he o

uter

Hev

eliu

s Fo

rmat

ion

from

Ori

enta

le h

as l

eft

de-

posi

ts o

n th

e cr

ater

rim

s. N

ote

the

furr

ow o

n th

e w

este

rn r

imof

Rus

sell

and

the

ridg

e on

the

rim

wal

l bet

wee

n St

ruve

and

Eddi

ngto

n. T

he li

ght

area

s m

ay h

ave

been

dep

osit

ed o

n th

eflo

or o

f St

ruve

by

Ori

enta

le a

nd n

ot fl

oode

d ov

er w

ith

mar

ela

va. O

r, t

he O

rien

tale

eje

cta

may

hav

e fa

llen

on p

rece

ding

lava

flow

s.

The

str

iate

d in

ner

Hev

eliu

s Fo

rmat

ion

grad

es i

nto

the

smoo

ther

out

er d

epos

its

in th

is p

hoto

. The

se d

epos

its

som

e-ti

mes

cre

ate

smoo

th p

lain

s in

are

as o

f m

ild

pree

xist

ing

topo

grap

hy, s

uch

as c

rate

r flo

ors.

The

eje

cta

from

the

earl

ier

(Pre

-Nec

tari

an)

crat

er S

chic

kard

is

so r

ugge

d th

at i

ts f

orm

can

be s

een

belo

w t

he n

ewer

eje

cta

blan

ket.

Floo

ding

of

the

floor

of

Schi

ckar

d w

ith

lava

see

ms

to h

ave

prec

eded

dep

osit

of O

rien

tale

eje

cta.

LO4-

167H

2Su

n El

evat

ion:

17.

40°

Alt

itud

e: 3

009.

04 k

m

45

Ori

enta

leBa

sin R

egio

n

The

dar

k, s

moo

th p

lain

s ar

eas

sout

h of

Byr

gius

see

m t

o be

isol

ated

lava

lake

s, a

ssoc

iate

d w

ith

no p

arti

cula

r to

pogr

aphi

cfe

atur

es.

The

se u

nits

esc

aped

hea

vy e

ject

a fr

om O

rien

tale

,bu

t nar

row

ly: n

ote

the

long

furr

ow fr

om O

rien

tale

just

to th

eso

uth

of t

he d

ark

plai

ns a

nd t

he h

eavi

ly s

tria

ted

terr

ain

furt

her

to t

he s

outh

as

wel

l. T

he fr

esh

crat

er o

n th

e ea

st r

imof

Byr

gius

is

very

you

ng;

Cle

men

tine

alb

edo

data

sho

w a

stro

ng r

ay p

atte

rn fr

om it

, whi

ch c

an b

e se

en o

n th

e flo

or o

fB

yrgi

us a

nd b

eyon

d. S

ome

of th

ese

rays

can

be

seen

cro

ssin

gth

e da

rk p

lain

s un

it n

ear

the

righ

t ed

ge o

f th

e ph

oto.

The

floor

of P

iazz

i als

o sh

ows

a sm

all a

rea

of s

moo

th d

ark

plai

ns.

The

rem

aind

er o

f tha

t floo

r is

mas

sive

ly fi

lled

wit

h O

rien

tale

Hev

eliu

s Fo

rmat

ion

mat

eria

l an

d m

ater

ial

from

the

nor

th-

wes

tern

rim

of P

iazz

i.

LO4-

167H

3Su

n El

evat

ion:

17.

40°

Alt

itud

e: 3

009.

04 k

m

46

Luna

r O

rbiter

Photo

gra

phic

Atla

s

The

floo

r of

Lam

arck

has

bee

n co

vere

d w

ith

stri

ated

mat

eria

lfr

om O

rien

tale

. Dar

win

is in

a la

rge

regi

on o

f fau

lts a

long

the

bord

er o

f Oce

anus

Pro

cella

rum

, pre

sum

ably

str

ess

frac

ture

sre

late

d to

the

for

mat

ion

of t

hat

giga

ntic

fea

ture

. The

str

ess

may

hav

e be

en in

duce

d by

an

impa

ct fo

rmin

g a

basi

n be

low

sout

hern

Oce

anus

Pro

cella

rum

(C

hapt

er I

mbr

ium

Bas

inR

egio

n) o

r m

ay h

ave

been

ind

uced

by

subs

eque

nt m

otio

nsof

the

cru

st a

nd m

antl

e ad

just

ing

to t

he r

edis

trib

utio

n of

mas

s of

Oce

anus

Pro

cella

rum

. The

faul

ts t

end

to b

e ci

rcum

-fe

rent

ial

and

radi

al t

o th

e bo

rder

of

Oce

anus

Pro

cella

rum

.R

imae

Dar

win

are

nea

rly

circ

umfe

rent

ial.

Rim

a Si

rsal

is,

ara

dial

faul

t mor

e th

an 3

00 k

m lo

ng, h

as it

s so

uthw

este

rn te

r-m

inus

in

a ne

twor

k of

fau

lts

(Rim

ae S

irsa

lis)

inte

rspe

rsed

wit

h R

imae

Dar

win

.

LO4-

168H

1Su

n El

evat

ion:

16.

50°

Alt

itud

e: 2

722.

18 k

m

47

Ori

enta

leBa

sin R

egio

n

Div

erse

sur

face

s of

the

out

er H

evel

ius

Form

atio

n ar

e sh

own

here

. U

nder

neat

h th

is e

ject

a bl

anke

t is

top

ogra

phy

from

olde

r im

pact

s su

ch a

s th

e tw

o cr

ater

s w

hose

floo

rs h

ave

been

flood

ed a

fter

the

Ori

enta

le e

vent

to fo

rm L

acus

Aes

tati

s. T

heR

imae

Dar

win

can

be

seen

to

mod

ify

the

stri

atio

ns f

rom

Ori

enta

le, s

o th

e ri

mae

mus

t hav

e be

en fo

rmed

late

r. A

cha

r-ac

teri

stic

tex

ture

of

the

oute

r H

evel

ius

Form

atio

n is

the

pitt

ed t

erra

in f

orm

ed b

y in

tens

e ar

rays

of

seco

ndar

y cr

ater

san

d se

cond

ary

crat

er c

hain

s in

the

are

a no

rth

of C

ruge

r.C

ruge

r’s

ejec

ta b

lank

et c

over

s an

d sm

ooth

s th

e sp

rink

ling

ofO

rien

tale

sec

onda

ries

. Cru

ger

is th

eref

ore

Late

Im

bria

n. T

heflo

or o

f Cru

ger

was

late

r re

surf

aced

by

mar

e la

va.

LO4-

168H

2Su

n El

evat

ion:

16.

50°

Alt

itud

e: 2

722.

18 k

m

48

Luna

r O

rbiter

Photo

gra

phic

Atla

s

The

Gri

mal

di B

asin

is o

lder

than

Ori

enta

le, a

s ca

n be

see

n by

the

Ori

enta

le s

tria

tion

s in

its

rin

gs. H

owev

er, i

ts m

are

floor

was

form

ed a

fter

Ori

enta

le. T

he s

moo

th a

rea

to t

he n

orth

of

Gri

mal

di a

t the

rad

ius

of L

ohrm

ann

lies

betw

een

two

ring

s of

the

Gri

mal

di B

asin

(se

e LO

4-16

8H2

for

the

sout

hern

par

t of

thes

e ri

ngs

and

a si

mila

r sm

ooth

are

a be

twee

n th

em).

Thi

sar

ea m

ay h

ave

had

a te

xtur

e si

mila

r to

the

plai

ns b

etw

een

the

Mon

tes

Roo

k an

d M

onte

s C

ordi

llera

bef

ore

bein

g co

vere

dw

ith

Ori

enta

le e

ject

a. A

hea

vy lo

be o

f pla

ins

depo

sits

(pr

oba-

bly

from

Ori

enta

le)

cove

rs t

he w

este

rn r

im o

f G

rim

aldi

,cr

osse

d by

the

sou

thea

st e

nds

of t

he R

imae

Ric

ciol

i. R

imae

Hev

eliu

s an

d R

imae

Ric

ciol

i are

par

t of

the

fra

ctur

e pa

tter

nar

ound

the

rim

of O

cean

us P

roce

llaru

m. T

he fl

ower

y pa

tter

nin

the

sou

thea

st q

uadr

ant

of G

rim

aldi

is

a de

velo

pmen

tar

tifa

ct.

LO4-

168H

3Su

n El

evat

ion:

16.

50°

Alt

itud

e: 2

722.

18 k

m

49

Ori

enta

leBa

sin R

egio

n

Where Oceanus Procellarum meetshighlands, the younger mare invadeslow-lying parts of the older highlandsjust as water meets a shoreline on Earth.Ejecta and secondaries from Krafft andCardanus overlie the mare, so they areyounger yet.

The lava flooding Eddington is ofvery low viscosity; it finds its way intoevery crevice. The flow may be not onlyhorizontal but may also seep up frombelow, through the fractured rock of thecrater floor.

The bright rays come from Coper-nican crater Glushko (LO4-174H2).

The linear trough just east of Hedin(radial to Orientale) terminates in aplains deposit, as if the trough wereplowed by a body of material that was(or became) molten. The long fault that crosses the floor of Hevelius andextends nearly to the rim of Riccioli hasa graben form (flat floor) in the high-lands outside of Hevelius, but is nar-rower (a rille) as it crosses the craterfloor at a lower elevation; this is whatone would expect of a fracture zone thathas a V shape in the vertical plane.

50

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Schi

ller

is a

rar

e el

onga

te c

rate

r. I

f it

was

form

ed b

y im

pact

,it

mus

t ha

ve b

een

by a

sm

all n

umbe

r of

pri

mar

y im

pact

ors

arri

ving

at

a sh

allo

w i

mpa

ct a

ngle

, pe

rhap

s as

low

as

3°.

Schi

ller

is m

ostl

y in

the

tro

ugh

betw

een

two

rais

ed r

ings

of

the

Pre-

Nec

tari

an S

chill

er-Z

ucch

ius

Bas

in.

Ori

enta

le e

ject

aha

s im

pact

ed m

are

that

has

floo

ded

this

bas

in b

efor

e th

eO

rien

tale

im

pact

. C

rate

rs W

eige

l, R

ost,

and

Nog

gera

th a

reex

ampl

es o

f ol

d cr

ater

s th

at h

ave

rece

ived

im

pact

s on

the

irri

ms.

Not

e th

e m

anne

r in

whi

ch th

e im

pact

s ca

use

the

crat

erw

alls

to c

olla

pse

onto

the

crat

er fl

oor.

LO4-

160H

1Su

n El

evat

ion:

17.

30°

Alt

itud

e: 3

012.

04 k

m

51

Ori

enta

leBa

sin R

egio

n

The

lig

hter

mat

eria

l in

the

int

erio

r of

cra

ter

Schi

ckar

d is

map

ped

as O

rien

tale

pla

ins-

form

ing

mat

eria

l lik

e th

at o

n th

eflo

or o

f War

gent

in a

nd P

hocy

lides

(LO

4-17

2H1)

. The

dar

ker

mat

eria

l in

side

Sch

icka

rd i

s m

appe

d as

mar

e ba

salt

, whi

chap

pear

s to

pre

date

the

pla

ins-

form

ing

mat

eria

l. Le

hman

nw

as fo

rmed

in th

e sa

me

peri

od a

s Sc

hick

ard

and

was

ove

rrun

by th

e pl

ains

-for

min

g m

ater

ial.

LO4-

160H

2Su

n El

evat

ion:

17.

30°

Alt

itud

e: 3

012.

04 k

m

52

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Sout

hwes

t of

Vie

ta is

an

irre

gula

r la

ke o

f da

rk m

are

mat

er-

ial,

the

wes

tern

mos

t m

embe

r of

a c

ircu

lar

patt

ern

of s

uch

feat

ures

(se

e C

hapt

er 6

). T

hese

lake

s ar

e si

mila

r to

tho

se i

nth

e ri

ngs

of t

he O

rien

tale

Bas

in, s

uch

as L

acus

Ver

itas

and

Lacu

s A

utum

nis.

How

ever

, the

re is

no

cent

ral d

epre

ssio

n or

mar

e un

it w

ithi

n th

is m

yste

riou

s ri

ng o

f la

kes.

The

are

aar

ound

the

m a

ppea

rs t

o be

cov

ered

wit

h pl

ains

-for

min

gm

ater

ial o

f the

out

er H

evel

ius

Form

atio

n.

LO4-

160H

3Su

n El

evat

ion:

17.

30°

Alt

itud

e: 3

012.

04 k

m

53

Ori

enta

leBa

sin R

egio

n

This chaotic region has been overlaid by ejecta from the Grimaldi Basin andthen by the Orientale Basin. Damoiseauappears to have been mostly floodedwith a heavy, viscous material, probablymolten or semimolten material fromOrientale. Some of this material hasbackflowed over and down the north-east crater wall. The lowest part of thefloor may have been flooded with marelike the flat-floored craters nearby. Thefloor material has fractured because ofthe cooling of the molten material.

Rimae Grimaldi and Rimae Sirsalisare part of the fracture pattern aroundthe border of Oceanus Procellarum.They can be seen to cross and modifythe secondary craters of Orientale, es-tablishing their younger age. The mainrima of the Sirsalis feature is the longestsuch feature on the Moon, leaving its mark on crater floors, rims, andejecta until it disappears into OceanusProcellarum (LO4-156H2). It is overlaidonly by the youngest crater in its path,the 13-km crater just to the south ofcrater Sirsalis.

The 22-km crater on the east rim ofByrgius is Copernican, with an exten-sive ray field. Some of these rays can beseen extending eastward. Henry Frereshas a slumped wall, possibly caused bythe impact that caused the 8-km youngcrater in its floor.

54

Luna

r O

rbiter

Photo

gra

phic

Atla

s

6.1. OverviewBasins, Maria, and HighlandsFigure 6.1 shows the Humorum Basin Region. The HumorumBasin is of the Nectarian Period, younger than the NubiumBasin and older than the Orientale Basin. It is sufficientlydistant from later basins that it has not been extensivelymodified, except by mare flooding of its floor and outer

trough. Its neighboring basins have been more modified,partly by Humorum itself. The highland regions to the south-east are relatively isolated from basins and preserve theheavily cratered surface of the crust. One would like to saythat they are “pristine” highlands, but in consideration of thefact that the highland surface is formed from intense crateringbombardment, that term is misleading. The point is that thishighland area has not been covered by such a heavy layer ofbasin ejecta that earlier cratering events have been obscured.

Chapter 6

Humorum Basin Region

Figure 6.1. LO4-137M. The Humorum Basin Region, the middle and lower area of this photo, includes the multi-ringed Humorum Basin itself, the NubiumBasin to the east, southern Oceanus Procellarum to the north, and the heavily cratered highland area to the south. The bright-rayed crater Tycho is also withinthis highland region. Northeast of the Humorum Basin Region is the Imbrium Basin and the bright craters (left to right) Aristarchus, Kepler, and Copernicus.

55

Hum

oru

mBa

sin R

egio

n

The juxtaposition of so many basins in the vicinity ofOceanus Procellarum has allowed rising mare lava to form anearly continuous sea, interrupted only by the rims of basinsand craters. The extent of this mare material is clear in theClementine albedo map of Figure 6.2.

The albedo map distinguishes between the bright crustmaterial, the dark mare material from the upper mantle, andthe rays, which are newly exposed crust material thrown outfrom young craters. The rays will darken with exposure tothe solar wind, which frees metallic iron from the surfacemineral grains in a process known as maturing. Rays fromimpacts into highlands that fall on mare are different in com-

position than mare, so the brightness contrast persists longafter maturing (Hawke, 2004). In additional time, gardeningby subsequent crater bombardment will cause the ray mater-ial to blend with the mare surface as well.

Apollo LandingsApollo 12, the second mission of humans on the Moon, ex-plored and returned samples from a shallow mare surface ofsoutheast Oceanus Procellarum (LO4-125H3). The missionconfirmed the character of maria established for MareTranquillitatis by Apollo 11. However, this mare proved tobe 500 million years younger and much richer in KREEP.Some samples appear to be from rays of Copernicus andestablish the time of that impact as 810 million years ago.

Apollo 12 landed within walking distance of Surveyor 3,establishing a new level of landing accuracy that permittedfuture missions to be targeted for even more interestinglanding sites. Parts of Surveyor 3 were returned to Earth andexamined for the character and rate of micrometeoroidimpacts.

Apollo 14 explored and sampled a geologic structurecalled the Fra Mauro Formation (LO4-120H3). The FraMauro Formation is material ejected from the ImbriumBasin. The samples, together with samples from Apollo 15,establish the time of the Imbrian impact as 3.85 billion yearsago. Other samples returned by Apollo 14 are older, in therange of 3.87 to 3.96 billion years, and may come fromimpacts in the subsurface below the Imbrian ejecta.

6.2. High-Resolution ImagesTable 6.1 shows the high-resolution images of the HumorumBasin Region in schematic form.

The following pages show the high-resolution subframesfrom south to north and west to east; that is, they are in theorder LO4-155H2, LO4-155H3, LO4-156H, LO4-148H1…LO4-108H3.

Subframes LO4-155H1, LO4-142H1, LO4-131H1, LO4-119H1, and LO4-107H1 are not included in print becausethey are redundant with adjacent exposures to the east andwest (they are included in the enclosed CD). The subframesof exposures 156H, 132H, and 113H have each been com-bined into full rectangular images.

56

Luna

r O

rbiter

Photo

gra

phic

Atla

s Figure 6.2. Clementine albedo display of the Humorum region. The floorsof the basins in this region are flooded with dark mare material. MareHumorum is left and above the center of the image and Mare Nubium is tothe upper right. Oceanus Procellarum is near the top of the image. Tycho’sbright ray pattern can be seen across both highland and mare surfaces. Thisis a section of the PIGWAD1 Mercator projection; the center of this figure isat 30° west longitude and 30° south latitude and the squares are 30° on aside. Sources: NRL and USGS, with permission.

0–27 N 162 157 150 144 138 133 126 121 114 109 102

0–27 S 161 156 149 143 137 132 125 120 113 108 101

27 S–56 S 160 155 148 142 136 131 124 119 112 107 100

56 S–90 S 154 130 118 106 094

Table 6.1. The cells shown in white represent the high-resolution photos of the Humorum Basin Region (LO4-XXX H1, -H2, and -H3, where XXX is thePhoto Number). The Orientale Basin Region is to the west, the Imbrium Basin Region is to the north, the Eastern Basins Region is to the northeast, theNectaris Basin Region is to the east, and the South Polar Region is to the south.

Longitude 62 W 58 W 49 W 41 W 35 W 30 W 23 W 16 W 10 W 3 W 4 Eat Equator

1 Planetary Interactive G.I.S.-on-the-Web Analyzable Database(USGS)

The

rid

ge i

n th

e lo

wer

rig

ht c

orne

r of

thi

s ph

oto

radi

ates

from

the

Sch

ille

r-Z

ucch

ius

Bas

in.

Subt

le s

tria

tion

s in

the

uppe

r le

ft r

adia

te fr

om O

rien

tale

.

LO4-

155H

2Su

n El

evat

ion:

17.

1°A

ltit

ude:

301

1.10

km

57

Hum

oru

mBa

sin R

egio

n

The

str

iati

ons

and

crat

er c

hain

s th

roug

h V

ieta

and

Fou

rier

are

radi

al t

o O

rien

tale

. T

he b

righ

tnes

s in

the

vic

init

y of

Four

ier

is d

ue t

o ra

ys f

rom

sm

all

prim

ary

crat

ers

of t

heC

oper

nica

n Pe

riod

. T

here

are

at

leas

t fo

ur;

one

is o

n th

eno

rthe

ast r

im o

f Vie

ta a

nd th

e ot

hers

are

abo

ut 5

0 km

nor

thof

Fou

rier

, ab

out

35 k

m n

orth

east

of

Four

ier,

and

abo

ut

35 k

m s

outh

east

of

Four

ier.

The

ir r

ay p

atte

rns

are

show

ncl

earl

y in

alb

edo

data

from

the

Cle

men

tine

mis

sion

.

LO4-

155H

3Su

n El

evat

ion:

17.

1°A

ltit

ude:

301

1.10

km

58

Luna

r O

rbiter

Photo

gra

phic

Atla

s

This frame shows the transitionbetween the highlands and southernOceanus Procellarum. The linearfeature that runs southeast fromHermann is an example of a wrinkleridge, also known as a mare ridge; suchfeatures often appear in a large maresurface. Their origin is unclear, but it may be related to cooling andsolidification of the lava.

As is common along the “shore” ofOceanus Procellarum, radial fracturesare revealed by rimae (rilles) at thesurface. Flooding by lava, cooling, andpossible isostatic adjustment are likelysources of the fracturing.

Note the 80-km buried crater at the edge of Oceanus Procellarum nearRimae Sirsalis; only part of its rimremains visible, like the smile of the Cheshire Cat. Striations betweenFontana and the mare support thehypothetical basin under southernOceanus Procellarum, as discussed inthe introduction to the chapter on theImbrium Basin Region (Chapter 7).

59

Hum

oru

mBa

sin R

egio

n

The

furr

ow a

nd r

idge

run

ning

nor

thea

st o

f Sch

eine

r is

pro

b-ab

ly e

ject

a fr

om t

he S

chill

er-Z

ucch

ius

Bas

in.

Sim

ilar,

les

spr

onou

nced

line

ar f

eatu

res

run

para

llel t

o th

e fu

rrow

in t

hem

iddl

e pa

rt o

f the

pic

ture

. Eje

cta

from

Cla

vius

par

tly o

verl

ies

the

furr

ow. T

he fl

oor

of th

e fu

rrow

is v

ery

flat a

nd s

moo

th; i

tm

ay b

e th

e re

sult

of

mol

ten

mat

eria

l in

the

bas

in e

ject

a.B

ayer

is

a co

ncen

tric

rin

g cr

ater

tha

t m

ay h

ave

pene

trat

edth

roug

h th

e Sc

hille

r-Z

ucch

ius

ejec

ta l

ayer

int

o m

ore

prim

i-ti

ve te

rrai

n be

low

.

LO4-

148H

1Su

n El

evat

ion:

17.

9°A

ltit

ude:

300

9.38

km

60

Luna

r O

rbiter

Photo

gra

phic

Atla

s

The

deg

rade

d st

ate

of M

ee in

dica

tes

that

it is

a r

elat

ivel

y ol

d,Pr

e-N

ecta

rian

cra

ter.

The

eje

cta

blan

ket

in t

he l

ower

rig

htha

lf of

the

phot

o ha

s be

en d

epos

ited

by

the

Hum

orum

Bas

into

the

nor

th. C

hain

s of

sm

all s

econ

dary

cra

ters

rad

iate

from

the

Ori

enta

le B

asin

far

to th

e no

rthw

est.

LO4-

148H

2Su

n El

evat

ion:

17.

9°A

ltit

ude:

300

9.38

km

61

Hum

oru

mBa

sin R

egio

n

Thi

s pi

ctur

e fe

atur

es a

n un

usua

l ran

ge o

f fea

ture

type

s. L

acus

Exce

llent

iae

is p

art o

f a r

ing

of m

are

lake

s in

a tr

ough

of t

heH

umor

um B

asin

. A

n ou

ter

ring

of

Hum

orum

can

be

seen

pass

ing

betw

een

Four

ier

and

Cla

usiu

s, in

terr

upte

d by

val

leys

blas

ted

by H

umor

um e

ject

a. R

imae

Pal

mie

ri a

nd R

imae

Dop

pelm

ayer

are

exa

mpl

es o

f the

rad

ial a

nd c

ircu

mfe

rent

ial

stre

ss fr

actu

res

near

the

edge

of M

are

Hum

orum

, who

se e

dge

can

be s

een

in th

e up

per

righ

t.

LO4-

148H

3Su

n El

evat

ion:

17.

9°A

ltit

ude:

300

9.38

km

62

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s pi

ctur

e ill

ustr

ates

the

str

uctu

re o

f th

e H

umor

um B

asin

. The

inne

r ba

sin

has

been

floo

ded

wit

h la

va. R

upes

Lie

big

(rup

es m

eans

a s

carp

, a c

liff)

may

have

bee

n fo

rmed

as

lava

ros

e pa

rtw

ay a

cros

s th

e sh

elf (

whi

ch m

ay h

ave

been

sim

ilar

to t

he M

aund

er F

orm

atio

n of

Ori

enta

le)

and

then

sub

side

d as

the

sour

ce p

lum

e re

laxe

d. A

s of

ten

is t

he c

ase

whe

re a

mar

e ha

s a

thin

edg

e, t

he

63

Hum

oru

mBa

sin R

egio

n

LO4-

149H

1Su

n El

evat

ion:

17.

5°A

ltit

ude:

272

0.28

km

shel

f is

cove

red

wit

h da

rk p

lain

s-fo

rmin

g m

ater

ial.

The

topo

grap

hic

ring

sur

-ro

unds

Mar

e H

umor

um w

est o

f thi

s fla

t pla

in. A

trou

gh o

utsi

de th

is fi

rst r

idge

has

been

par

tly

flood

ed w

ith

lava

. A s

econ

d ci

rcum

fere

ntia

l rid

ge, l

ower

and

less

con

tinu

ous

than

the

firs

t, lie

s ou

tsid

e th

e tr

ough

. Mos

t of

the

rim

a fe

a-tu

res

reve

al s

tres

s fa

ults

from

the

mar

e flo

odin

g an

d co

olin

g pr

oces

ses.

It h

as b

een

sugg

este

d th

at M

ons

Han

stee

n co

uld

be a

n Ea

rth-

styl

e vo

lcan

o (i

tlo

oks

muc

h lik

e M

t. Fu

ji, fo

r ex

ampl

e). H

owev

er, t

hat w

ould

req

uire

a s

ourc

eof

hig

h-vi

scos

ity

lava

onl

y a

few

kilo

met

ers

away

fro

m B

illy,

whi

ch h

as b

een

flood

ed w

ith

typi

cal l

ow-v

isco

sity

lava

. Ano

ther

exp

lana

tion

wou

ld b

e th

at it

isa

rem

nant

of

an in

teri

or b

asin

rin

g (l

ike

Mon

tes

Roo

k, w

hich

is r

ich

in s

uch

pyra

mid

al b

lock

s).

64

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

149H

2Su

n El

evat

ion:

17.

5°A

ltit

ude:

272

0.28

km

Thi

s is

the

sout

heas

t sec

tion

of O

cean

us P

roce

llaru

m. M

any

furt

her

pict

ures

of

this

gig

anti

c m

are

cove

red

in t

he c

hapt

er o

n th

e Im

briu

m B

asin

(C

hapt

er7)

. Int

eres

ting

feat

ures

of t

his

pict

ure

are

the

segm

ents

of c

rate

r w

alls

that

hav

esu

rviv

ed i

nund

atio

n by

the

mar

e la

va. S

ome

of t

he w

alls

are

so

high

tha

t it

seem

s th

at t

he m

issi

ng s

egm

ents

mus

t ha

ve m

elte

d in

to t

he m

are

floor

. The

righ

t sid

e of

this

pic

ture

con

tain

s la

rge

swir

ls o

f dev

elop

men

t bub

bles

.

65

Hum

oru

mBa

sin R

egio

n

LO4-

149H

3Su

n El

evat

ion:

17.

5°A

ltit

ude:

272

0.28

km

Thi

ck e

ject

a an

d se

cond

ary

crat

ers

of t

he H

umor

um B

asin

cove

r th

is a

rea.

Thi

s te

rrai

n is

cal

led

the

Vit

ello

For

mat

ion

(cra

ter

Vit

ello

is

in L

O4-

142H

3); i

t is

the

equ

ival

ent

of t

heH

evel

ius

Form

atio

n of

the

Ori

enta

le B

asin

or

the

Fra

Mau

roFo

rmat

ion

of t

he I

mbr

ium

Bas

in.

The

tw

o Er

atos

then

ian

crat

ers

that

obs

cure

Hai

nzel

may

hav

e la

nded

ess

enti

ally

sim

ulta

neou

sly,

as

indi

cate

d by

the

stra

ight

seg

men

t bet

wee

nth

em. H

ainz

el h

ad a

lrea

dy b

een

form

ed w

hen

they

lan

ded,

alth

ough

the

inte

rval

may

hav

e be

en s

hort

.

66

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

142H

2Su

n El

evat

ion:

19.

5°A

ltit

ude:

300

6.60

km

One

rin

g of

Hum

orum

pas

ses

thro

ugh

or n

ear

Vit

ello

.A

noth

er,

prob

ably

the

hig

hest

rin

g, p

asse

s ju

st n

orth

of

Lacu

s Ex

celle

ntia

e, w

hich

floo

ds a

tro

ugh

exte

rnal

to

that

ring

. T

he m

ater

ial

on t

he fl

oor

of V

itel

lo a

ppea

rs t

o ha

vebe

en m

olte

n be

fore

har

deni

ng a

nd t

hen

frac

turi

ng,

very

muc

h lik

e K

opff

in

Ori

enta

le (

LO4-

187H

2). D

oppe

lmay

er i

ssl

ante

d; i

t m

ay h

ave

form

ed p

artl

y on

the

bas

in fl

oor

and

part

ly o

n a

terr

ace

or s

callo

p of

the

rim

. As

a re

sult

, it i

s on

lypa

rtly

floo

ded.

If

Puis

eux

was

floo

ded

thro

ugh

a ve

ry s

mal

lbr

eak

in it

s no

rthe

rn r

im (

and

not f

rom

bel

ow),

the

visc

osit

yof

the

lava

mus

t hav

e be

en v

ery

low

to s

prea

d ev

enly

ove

r th

ecr

ater

floo

r.

LO4-

142H

3Su

n El

evat

ion:

19.

5°A

ltit

ude:

300

6.60

km

67

Hum

oru

mBa

sin R

egio

n

Alt

houg

h th

e H

umor

um B

asin

doe

s no

t app

ear

to b

e as

larg

eas

the

Ori

enta

le B

asin

, th

e ce

ntra

l m

are

is a

bout

the

sam

esi

ze, p

roba

bly

beca

use

the

crus

t is

thi

nner

in t

he H

umor

umre

gion

. As

a re

sult

, the

inne

r de

tail

and

perh

aps

inne

r ri

ngs

are

lost

bec

ause

of t

he fl

oodi

ng o

f lav

a. In

stea

d th

ere

is a

ver

ysm

ooth

, but

not

feat

urel

ess,

sur

face

. The

sca

rp a

t the

wes

tern

edge

of

the

mar

e (R

upes

Lie

big)

sug

gest

s th

at t

he m

are

surf

ace

rose

to

a le

vel

high

er t

han

its

pres

ent

elev

atio

n an

d th

en s

ubsi

ded

a bi

t, pa

rtly

as

a re

sult

of

cont

ract

ion

onco

olin

g. S

tres

ses

indu

ced

by t

he s

ubsi

denc

e fin

d su

rfac

e ex

-pr

essi

on i

n R

imae

Dop

pelm

ayer

and

wri

nkle

rid

ges

such

as

the

one

near

the

left

edg

e of

the

pic

ture

. The

bri

ght

stre

aks

acro

ss th

e m

are

rays

from

Tyc

ho.

68

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

143H

1Su

n El

evat

ion:

18.

8°A

ltit

ude:

271

9.10

km

Gas

send

i w

as f

orm

ed b

y an

im

pact

pre

cise

ly o

n th

e sc

arp

boun

ding

Mar

e H

umor

um. I

ts fl

oor,

slig

htly

low

er t

han

the

near

by la

va s

urfa

ce, a

ppea

rs to

hav

e be

en a

mel

t she

et, h

eavi

lyfr

actu

red

upon

coo

ling

or is

osta

tic a

djus

tmen

t. A

nea

rly

con-

tinuo

us r

im h

as p

rote

cted

it fr

om fl

oodi

ng w

ith la

va e

xcep

t for

a sm

all b

reac

h in

the

sou

ther

n ri

m, w

hich

has

allo

wed

som

ela

va t

o en

ter

a se

ctor

of

the

floor

. The

floo

r of

Gas

send

i ha

sbe

en h

eavi

ly fr

actu

red,

pos

sibl

y by

upw

ard

pres

sure

of l

ava

ona

mel

t sh

eet.

Letr

onne

has

bee

n fu

lly b

reac

hed

and

flood

edfr

om th

e no

rth

by O

cean

us P

roce

llaru

m.

LO4-

143H

2Su

n El

evat

ion:

18.

8°A

ltit

ude:

271

9.10

km

69

Hum

oru

mBa

sin R

egio

n

The

cro

ss m

arks

the

June

196

6 la

ndin

g of

Sur

veyo

r 1,

who

seso

ft la

ndin

g co

nfirm

ed th

e sa

fe b

eari

ng s

tren

gth

of th

e lu

nar

soil,

pre

viou

sly

affir

med

by

Luna

9. T

he S

urve

yor

1 ca

mer

ash

owed

the

loc

al s

urfa

ce t

o be

flat

, w

ith

boul

ders

nea

r a

crat

er i

n th

e di

stan

ce. S

urve

yor

1 la

nded

in

a re

mna

nt o

f a

crat

er r

im le

ft b

ehin

d by

an

inun

date

d “g

host

cra

ter,

” in

for-

mal

ly c

alle

d th

e Fl

amst

eed

ring

. Dor

sa R

ubey

is a

n ex

ampl

eof

a w

rink

le r

idge

, a

com

mon

fea

ture

of

mar

e su

rfac

es.

Asm

alle

r ri

dge

form

s an

inte

rior

rin

g w

ithi

n th

e ve

stig

ial r

imof

the

Flam

stee

d ri

ng.

70

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

143H

3Su

n El

evat

ion:

18.

8°A

ltit

ude:

271

9.10

km

Cla

vius

, at

225

km i

n di

amet

er, i

s in

a t

rans

itio

n re

gion

bet

wee

n cr

ater

s an

dba

sins

. T

he r

im s

how

s m

ulti

ple

colla

pse

feat

ures

, pr

esen

ting

a s

callo

ped

appe

aran

ce. T

he p

eak

stru

ctur

e is

com

plex

, an

inte

rmed

iate

ste

p to

an

inne

rri

ng. T

he s

trea

ks o

n th

e flo

or o

f C

lavi

us a

nd L

ongo

mon

tanu

s ar

e ra

ys f

rom

Tyc

ho. P

orte

r ha

s hi

t the

nor

thea

ster

n co

rner

of C

lavi

us, p

iling

the

mat

eria

l of

the

rim

of C

lavi

us n

eatly

to th

at s

ide.

71

Hum

oru

mBa

sin R

egio

n

LO4-

136H

1Su

n El

evat

ion:

19.

2°A

ltit

ude:

300

2.96

km

The

gou

ges

in t

he n

orth

ern

rim

of

Long

omon

tanu

s ar

e fr

om t

he d

irec

tion

of

the

Nub

ium

and

Im

briu

m B

asin

s an

d ar

e lik

ely

to b

e se

cond

arie

s fr

om o

ne

of th

ose

basi

ns. T

he fo

rmat

ion

of th

e go

uges

sug

gest

s th

at th

e in

cide

nce

angl

eof

the

sec

onda

ry im

pact

ors

was

abo

ut t

he s

ame

as t

he a

ngle

of t

he r

im b

efor

eim

pact

. The

val

ley

of L

acus

Tim

oris

may

hav

e be

en g

ouge

d ou

t by

ejec

ta fr

omth

e H

umor

um B

asin

.

72

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

136H

2Su

n El

evat

ion:

19.

2°A

ltit

ude:

300

2.96

km

Palu

s Ep

idem

iaru

m m

ay b

e si

mila

r to

the

lak

es i

n th

e tr

ough

rin

g ar

ound

basi

ns, s

impl

y an

unu

sual

ly la

rge

area

of m

are

in th

e tr

ough

. Lav

a fr

om P

alus

Epid

emia

rum

see

ms

to h

ave

flow

ed i

nto

Mar

e H

umor

um t

hrou

gh a

sin

uous

chan

nel t

hat p

asse

s th

roug

h a

valle

y in

the

ring

that

bou

nds

Mar

e H

umor

um.

73

Hum

oru

mBa

sin R

egio

n

LO4-

136H

3Su

n El

evat

ion:

19.

2°A

ltit

ude:

300

2.96

km

The

rad

ial a

nd c

ircu

mfe

rent

ial R

imae

Ram

sden

are

typ

ical

of

the

surf

ace

fea-

ture

s ov

erly

ing

stre

ss f

ract

ures

nea

r th

e ed

ge o

f m

aria

. R

upes

Kel

vin

is t

hebo

unda

ry o

f th

e ri

ng t

hat

boun

ds M

are

Hum

orum

; thi

s ri

ng is

sim

ilar

to t

heou

ter

rang

e of

Mon

tes

Roo

k. A

noth

er h

ighe

r ri

ng p

asse

s th

roug

h C

apua

nus.

Wri

nkle

rid

ges

(dor

sa)

such

as

thos

e in

the

mid

dle

of t

his

pict

ure

ofte

n ap

pear

on

mar

e su

rfac

es.

Her

e th

ey f

orm

ase

ries

of

circ

umfe

rent

ial

ridg

es.

The

y co

uld

have

bee

nfo

rmed

by

extr

usio

n of

the

mar

e la

va a

long

cra

cks

in t

heco

oled

and

har

dene

d su

rfac

e. S

carp

s in

the

mar

e su

rfac

e(b

etw

een

the

ridg

es a

nd t

he r

im)

indi

cate

tha

t th

e di

rect

ion

of lo

w-v

isco

sity

lava

flow

ed fr

om th

e ce

nter

tow

ard

the

edge

of th

e m

are.

74

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

137H

1Su

n El

evat

ion:

18.

8°A

ltit

ude:

271

8.01

km

Thi

s ph

oto

show

s a

brea

ch in

the

rim

of M

are

Hum

orum

that

allo

wed

the

mar

e su

rfac

e to

con

nect

wit

h th

at o

f O

cean

usPr

ocel

laru

m i

n th

e no

rthe

ast

corn

er o

f th

is p

hoto

. Per

haps

the

lava

ros

e w

ithi

n M

are

Hum

orum

to

a po

int

whe

re i

tov

erflo

wed

the

wal

l an

d op

ened

the

bre

ach.

The

dar

ker

(you

nger

?) s

urfa

ce o

f M

are

Hum

orum

see

ms

to h

ave

ex-

tend

ed t

hrou

gh t

he b

reac

h to

war

d O

cean

us P

roce

llaru

m.

Scar

ps in

dica

ting

flow

bou

ndar

ies

and

the

sinu

ous

chan

nels

of R

imae

Her

igon

ius

may

be

rela

ted

to th

e m

ovem

ent o

f lav

afr

om M

are

Hum

orum

int

o (o

r on

to)

Oce

anus

Pro

cella

rum

.D

orsa

Ew

ing

and

othe

r ne

arby

wri

nkle

rid

ges

may

be

rela

ted

to u

nder

lyin

g to

pogr

aphy

; the

mar

e is

sha

llow

her

e (s

ee t

hegh

ost c

rate

rs in

LO

4-13

7H3)

.

75

Hum

oru

mBa

sin R

egio

n

LO4-

137H

2Su

n El

evat

ion:

18.

8°A

ltit

ude:

271

9.10

km

The

re w

as p

roba

bly

an e

ject

a bl

anke

t fr

om t

he H

umor

um B

asin

her

e, b

ut i

tw

as c

over

ed b

y th

e m

are

surf

ace

of O

cean

us P

roce

llaru

m,

just

as

it n

earl

yer

ased

the

larg

e “g

host

” cr

ater

s.

76

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

137H

3Su

n El

evat

ion:

18.

8°A

ltit

ude:

271

9.10

km

The

str

iati

ons

betw

een

Hai

ding

er a

nd H

eins

ius

are

ejec

ta fr

om th

e H

umor

umB

asin

, si

mil

ar i

n na

ture

to

the

inne

r H

evel

ius

Form

atio

n of

the

Ori

enta

leB

asin

. Cra

ter

chai

ns in

Wilh

elm

are

rad

ial t

o bo

th t

he N

ubiu

m B

asin

and

the

mor

e re

mot

e Im

briu

m B

asin

. Thi

s ar

ea is

als

o ov

erla

in w

ith

rays

from

Tyc

ho.

77

Hum

oru

mBa

sin R

egio

n

LO4-

131H

2Su

n El

evat

ion:

19.

5°A

ltit

ude:

299

9.00

km

The

dee

per

(sm

ooth

er, r

elat

ivel

y fe

atur

eles

s) p

art o

f Pal

us E

pide

mia

rum

is th

ela

rges

t of a

set

of s

mal

l tra

cts

of m

are

form

ed in

a tr

ough

rin

g of

the

Hum

orum

Bas

in. I

ts s

ize

may

be

influ

ence

d by

an

inte

rsec

tion

of

the

Hum

orum

tro

ugh

wit

h an

ear

lier

trou

gh o

f th

e N

ubiu

m B

asin

. Alt

houg

h th

ese

smal

l mar

e un

its

coul

d al

l be

term

ed “

lacu

s” (

lake

), th

e ex

tens

ion

of P

alus

Epi

dem

iaru

m to

the

78

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

131H

3Su

n El

evat

ion:

19.

5°A

ltit

ude:

299

9.00

km

sout

heas

t ap

pear

s to

be

rela

tive

ly s

hallo

w,

so t

his

feat

ure

has

been

nam

ed“p

alus

” (s

wam

p). R

upes

Mer

cato

r is

par

t of

the

deg

rade

d ri

m o

f th

e N

ubiu

mB

asin

. Mer

cato

r ha

s im

pact

ed th

is r

im, a

nd th

en s

omew

hat l

ater

Cam

panu

s as

wel

l. T

he r

elat

ive

ages

of C

ampa

nus

and

Mer

cato

r ar

e in

dica

ted

by th

e “w

orn-

away

” ap

pear

ance

of M

erca

tor

and

its

ejec

ta.

Montes Riphaeus is a remnant of veryold crust. It may be an arc of the rim of a large crater containing MareCognitum. The intersecting ray patternscome from Copernicus to the northeastand Kepler to the northwest. The small,sharp, rayed craters such as Euclidescould be secondaries from Copernicus.

In the lower left of this picture, thedark mare is probably in a trough of theHumorum Basin. The remains of anouter ring appear as an island above it.

Rimae Hippalus are nearly concentricwith the Humorum Basin, but theytrend outward toward the north insteadof curving around to the northwest.Rima Agatharchides is part of the totalsystem of rimae, which is influenced byMare Humorum and Mare Nubium andthe underlying basin structures. Theserimae traverse older features like therim of Hippalus, but are interrupted by newer craters such as the one about30 km southeast of Hippalus. The ejectafrom the newer craters fills in the rimae.The bounding ring of the HumorumBasin has been suppressed here, pos-sibly because of interactions with thepreexisting ring and melt sheet of theNubium Basin.

79

Hum

oru

mBa

sin R

egio

n

Whi

ch c

ame

first

, Cla

vius

or

Mag

inus

? T

he r

elev

ant

brig

ht-

ness

of t

he fl

oor

of M

agin

us is

due

to it

s pr

oxim

ity

to T

ycho

,so

tha

t is

not

a c

lue.

It

is d

iffic

ult

to s

ee s

tron

g ev

iden

cew

heth

er t

he e

ject

a of

Cla

vius

ove

rlie

s th

at o

f Mag

inus

or

the

reve

rse,

pos

sibl

y be

caus

e of

the

ove

rbur

den

of e

ject

a fr

omnu

mer

ous

othe

r cr

ater

s an

d ba

sins

. M

agin

us s

how

s m

ore

crat

erin

g ar

ound

its

rim

tha

n C

lavi

us.

Thi

s es

tabl

ishe

s a

sign

ifica

ntly

old

er a

ge fo

r M

agin

us, w

hich

is m

appe

d as

Pre

-N

ecta

rian

whe

reas

Cla

vius

is m

appe

d as

Nec

tari

an. S

tria

tion

son

the

rim

of M

agin

us in

the

dire

ctio

n of

Cla

vius

are

map

ped

as e

ject

a fr

om C

lavi

us.

80

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

124H

1Su

n El

evat

ion:

19.

9°A

ltit

ude:

299

4.47

km

The

floo

r, r

im, a

nd r

ays

of T

ycho

are

ver

y br

ight

, ind

icat

ing

its

youn

g ag

e (C

oper

nica

n Pe

riod

). C

onse

quen

tly,

the

re h

asno

t be

en t

ime

for

sign

ifica

nt d

egra

dati

on o

f it

s to

pogr

aphy

.T

he c

entr

al p

eak

is t

ypic

al o

f cr

ater

s of

thi

s si

ze, f

orm

ed o

fm

ater

ial t

hrow

n di

rect

ly u

pwar

d by

the

com

pres

sion

al s

hock

wav

e re

boun

ding

from

ori

gina

l cru

st b

elow

the

bou

ndar

y of

frac

ture

d cr

ater

mat

eria

l. Su

rvey

or 7

was

bol

dly

targ

eted

for

the

fres

h ej

ecta

fro

m T

ycho

, la

ndin

g in

Jan

uary

196

8. T

heSu

rvey

or 7

cam

era

show

ed a

sur

face

of b

lock

s up

to

a m

eter

in s

ize.

The

sur

face

was

rou

ghly

tex

ture

d, b

ut w

ith

few

ercr

ater

s th

an w

ere

seen

in

the

mar

e la

ndin

g si

tes.

The

low

erra

te o

f cra

teri

ng r

esul

ts fr

om th

e yo

ung

age

of th

e te

rrai

n.

LO4-

124H

2Su

n El

evat

ion:

19.

9°A

ltit

ude:

299

4.47

km

81

Hum

oru

mBa

sin R

egio

n

The

Nub

ium

Bas

in is

muc

h ol

der

than

the

Hum

orum

Bas

in.

Exte

nsiv

e flo

odin

g, i

nflue

nced

by

its

prox

imit

y to

Oce

anus

Proc

ella

rum

, has

hid

den

muc

h of

its

rid

ge a

nd t

roug

h ri

ngst

ruct

ures

. Rup

es M

erca

tor

is a

par

t of

a r

idge

, pro

babl

y th

eto

pogr

aphi

c ri

ng, o

f the

Nub

ium

Bas

in. T

his

ring

is e

llipt

ical

in s

hape

, an

indi

cati

on o

f an

obliq

ue im

pact

.

82

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

124H

3Su

n El

evat

ion:

19.

9°A

ltit

ude:

299

4.47

km

The

con

cent

ric

stru

ctur

e of

Kon

ig a

nd t

he s

light

ly s

mal

ler

crat

er to

the

east

of i

t sug

gest

that

they

hav

e bo

ttom

ed o

ut in

a la

yer

belo

w t

he s

urfa

ce o

f M

are

Nub

ium

. The

sm

ooth

top

laye

r of

the

cra

ter

wal

l of

Bul

liald

us a

nd g

host

cra

ter

rim

ssu

ch a

s K

ies

sugg

est

a si

mila

r sh

allo

w d

epth

to

the

mar

e, in

the

rang

e of

1 t

o 2

km.

The

ray

fro

m T

ycho

tha

t ex

tend

sac

ross

the

mar

e al

so c

over

s th

e ej

ecta

of

Bul

lial

dus.

Thi

sej

ecta

is

thic

k fo

r ab

out

one

crat

er r

adiu

s ou

tsid

e of

Bul

liald

us a

nd th

en b

reak

s up

into

cha

ins

of s

mal

l sec

onda

rycr

ater

s. R

ima

Hes

iodu

s is

a t

ypic

al s

tres

s fr

actu

re n

ear

the

edge

of M

are

Nub

ium

.

LO4-

125H

1Su

n El

evat

ion:

18.

9°A

ltit

ude:

271

6.97

km

83

Hum

oru

mBa

sin R

egio

n

Mar

e C

ogni

tum

(kn

own

sea)

was

so

nam

ed b

ecau

se R

ange

r7,

the

first

fully

suc

cess

ful R

ange

r, tr

ansm

itte

d a

nest

ed s

et o

fpi

ctur

es. T

he r

esol

utio

n of

the

las

t pi

ctur

e w

as s

uffic

ient

to

show

cra

ters

as

smal

l as

1 m

in

diam

eter

, m

ore

than

tw

oor

ders

of

mag

nitu

de b

ette

r th

an t

he r

esol

utio

n of

Ear

th-

base

d ph

otog

raph

y. T

he p

ictu

res

esta

blis

hed

that

the

surf

ace

smoo

thne

ss o

f m

are

surf

aces

sim

ilar

to t

hat

phot

ogra

phed

wou

ld b

e su

itab

le fo

r an

Apo

llo la

ndin

g an

d as

tron

aut e

xcur

-si

ons.

The

pre

senc

e of

blo

cks

in s

ome

of t

he R

ange

r 7

pic-

ture

s in

dica

ted

sign

ifica

nt b

eari

ng s

tren

gth,

but

dou

bt s

till

rem

aine

d in

som

e m

inds

on

this

sub

ject

. D

arne

y is

on

the

rim

of a

240

-km

cra

ter

that

und

erlie

s M

are

Cog

nitu

m.

84

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

125H

2Su

n El

evat

ion:

18.

9°A

ltit

ude:

271

6.97

km

LO4-

125H

3Su

n El

evat

ion:

18.

9°A

ltit

ude:

271

6.97

km

85

Hum

oru

mBa

sin R

egio

n

The

sou

thea

st r

ange

of

Mon

tes

Rip

haeu

s is

a s

ecto

r of

the

rim

of

the

crat

er t

hat

unde

rlie

s M

are

Cog

nitu

m. T

he r

ays

inth

e up

per

righ

t cor

ner

of th

is p

ictu

re c

ome

from

Cop

erni

cus.

Mar

e In

sula

rum

(se

a of

isl

ands

, na

med

for

the

old

top

o-gr

aphy

tha

t pr

otru

des)

may

be

an e

xten

sion

of

Oce

anus

Proc

ella

rum

or

may

be

part

of

an o

uter

tro

ugh

of t

heIm

briu

m B

asin

. Lun

a 5

cras

hed

(May

196

5) b

ecau

se it

s re

tro-

rock

et fa

iled

to fi

re. S

urve

yor

3, t

he s

econ

d Su

rvey

or t

o su

c-ce

ssfu

lly l

and

(Apr

il 19

67),

con

firm

ed t

he s

uita

bilit

y of

thi

sar

ea f

or a

n A

pollo

lan

ding

, w

hich

was

acc

ompl

ishe

d by

Apo

llo 1

2 (N

ovem

ber

1969

). T

he t

ouch

dow

n of

Apo

llo 1

2,th

e se

cond

man

ned

land

ing,

was

abo

ut 1

60 m

from

Sur

veyo

r3;

the

astr

onau

ts v

isit

ed th

e Su

rvey

or a

nd r

emov

ed p

arts

for

exam

inat

ion

on e

arth

.

Alt

houg

h th

e flo

or, r

im, a

nd r

ays

of T

ycho

are

ver

y br

ight

,th

e in

ner

ejec

ta (

out

to a

bout

one

dia

met

er f

rom

the

rim

) is

only

as

brig

ht a

s th

e ty

pica

l hig

hlan

ds. T

his

dim

mer

eje

cta

ispr

obab

ly r

elat

ivel

y co

arse

and

fro

m a

dee

per

laye

r of

the

targ

et. F

urro

ws

in th

e ej

ecta

bla

nket

are

lim

ited

to th

e da

rker

area

, but

cha

ins

of s

mal

l se

cond

ary

crat

ers

exte

nd t

hrou

ghbo

th d

arke

r an

d lig

hter

are

as.

The

lig

ht e

ject

a m

ater

ial

ispr

obab

ly v

ery

fine

grai

ned.

Suc

h m

ater

ial

dark

ens

wit

h ex

-po

sure

to

the

sola

r w

ind

(whi

ch f

rees

iro

n pa

rtic

les

wit

hin

the

grai

ns)

and

from

met

eoro

id g

arde

ning

(w

hich

mix

es t

heun

derl

ying

soi

l wit

h th

e gr

ains

). T

he T

ycho

impa

ct o

ccur

red

too

rece

ntly

(on

ly a

bout

100

mill

ion

year

s ag

o) fo

r th

e ra

ys to

have

had

tim

e to

dar

ken.

86

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

119H

2Su

n El

evat

ion:

20.

3°A

ltit

ude:

299

0.55

km

Pita

tus

is a

bout

the

sam

e si

ze a

s T

ycho

and

sho

ws

a si

mila

rce

ntra

l pe

ak.

How

ever

, it

is

muc

h ol

der

(Nec

tari

an).

The

chai

n of

sec

onda

ries

fro

m t

he I

mbr

ium

Bas

in is

sup

erpo

sed

on t

he r

im o

f Pi

tatu

s, a

nd i

ts fl

oor

was

floo

ded

alon

g w

ith

that

of

the

Nub

ium

Bas

in. R

ays

from

Tyc

ho a

ppea

r on

bot

hth

e flo

or o

f Pit

atus

and

Mar

e N

ubiu

m. R

imae

Pit

atus

, aro

und

the

edge

of t

he fl

oor

of P

itat

us, h

ave

been

att

ribu

ted

to fr

ac-

ture

s ca

used

by

uplif

t of t

he fl

oor,

per

haps

in th

e co

urse

of i

tsflo

odin

g. I

t ap

pear

s th

at l

ava

has

flow

ed f

rom

the

floo

r of

Pita

tus

into

Hes

iodu

s th

roug

h th

e w

ide

chan

nel i

n th

e ri

ms.

LO4-

119H

3Su

n El

evat

ion:

20.

3°A

ltit

ude:

299

0.55

km

87

Hum

oru

mBa

sin R

egio

n

Wol

f, sh

aped

like

a V

alen

tine

hea

rt, w

ould

req

uire

a s

alvo

of f

our

crat

ers

if it

wer

e sh

aped

by

impa

ct. A

n al

tern

ate

expl

anat

ion

is th

at it

is a

cal

dera

form

edby

inte

rnal

pro

cess

es d

urin

g th

e fo

rmat

ion

of t

he m

are.

The

con

cent

ric

inne

rri

ng o

f th

e sm

all

crat

er t

o th

e so

uthw

est

of H

esio

dus

may

ind

icat

e th

at t

he

88

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

120H

1Su

n El

evat

ion:

20.

1°A

ltit

ude:

271

7.50

km

crat

er “

bott

omed

out

” in

the

rel

ativ

ely

shal

low

laye

r of

lava

nea

r th

e ed

ge o

fM

are

Nub

ium

. Not

e th

at s

imila

r-si

zed

and

larg

er c

rate

rs s

uch

as N

icol

let

dono

t sho

w s

imila

r m

orph

olog

y in

the

mor

e ce

ntra

l, pr

esum

ably

dee

per,

par

ts o

fth

e m

are.

The

nor

ther

n ri

m o

f th

e N

ubiu

m B

asin

, as

infe

rred

fro

m t

he n

earl

y ci

rcul

arsh

ape

of t

he r

ing

arou

nd M

are

Nub

ium

, run

s th

roug

h th

e ri

dges

nea

r R

imae

Ope

lt a

nd s

outh

of G

ueri

cke.

The

eje

cta

blan

ket f

rom

the

Nub

ium

Bas

in p

rob-

ably

sur

vive

s un

der

the

ridg

es a

nd tr

ough

s in

the

vici

nity

of G

ueri

cke,

but

the

89

Hum

oru

mBa

sin R

egio

n

LO4-

120H

2Su

n El

evat

ion:

20.

1°A

ltit

ude:

271

7.50

km

stri

atio

ns a

re f

rom

Im

briu

m.

Cop

erni

cus

is t

he s

ourc

e of

the

bri

ght

rays

runn

ing

nort

h to

sou

th th

roug

h th

is p

ictu

re. M

are

Nub

ium

app

ears

to b

e co

n-ne

cted

to

Mar

e C

ogni

tum

(th

e da

rk a

rea

nort

h of

Rim

ae O

pelt

) th

roug

h a

broa

d ch

anne

l eas

t of R

imae

Ope

lt.

The

hea

vily

furr

owed

lum

py d

epos

its

nort

h an

d so

uth

of F

ra M

auro

are

cal

led

the

Fra

Mau

ro F

orm

atio

n, n

ow k

now

n to

be

ejec

ta f

rom

the

Im

briu

m B

asin

,af

ter

anal

ysis

of

rock

s re

turn

ed f

rom

the

Apo

llo 1

4 m

issi

on. T

he F

ra M

auro

Form

atio

n co

rres

pond

s (a

s a

terr

ane

type

) to

the

inne

r H

evel

ius

Form

atio

n of

the

Ori

enta

le B

asin

. A

mon

g th

e 43

kg

of r

ock

retu

rned

by

Apo

llo 1

4 ar

e

90

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

120H

3Su

n El

evat

ion:

20.

1°A

ltit

ude:

271

7.50

km

sam

ples

fro

m n

ear

the

rim

of

the

370-

m C

one

crat

er. T

his

crat

er b

roug

ht u

pro

cks

from

the

Fra

Mau

ro F

orm

atio

n th

at h

ad n

ot b

een

grou

nd u

p in

the

“top

soil”

of

the

rego

lith.

Ana

lysi

s of

the

se r

ocks

has

est

ablis

hed

the

tim

e of

the

Imbr

ium

impa

ct a

s ab

out 3

.8 b

illio

n ye

ars

ago.

The

are

a ar

ound

Jac

obi,

beyo

nd th

e T

ycho

ray

s ne

ar th

e to

p,is

abo

ut a

s fa

r fr

om m

are,

bas

ins,

and

lar

ge c

rate

rs a

s on

eca

n ge

t on

the

near

sid

e of

the

Moo

n. I

t is

calle

d “i

nter

crat

erte

rran

e” (

a te

rran

e is

an

area

wit

h sp

ecifi

c fo

rmat

ion

cha-

ract

eris

tics

) an

d is

bel

ieve

d to

be

Pre-

Nec

tari

an i

n ag

e.C

lem

enti

ne a

ltit

ude

data

sho

w a

dep

ress

ion

equi

vale

nt t

o a

200-

km c

rate

r ce

nter

ed o

n th

e no

rthe

ast

rim

of

Jaco

bi(C

uvie

r w

ould

be

beyo

nd t

he r

im o

f su

ch a

cra

ter)

. Suc

h an

anci

ent,

degr

aded

cra

ter

may

exp

lain

the

rel

ativ

e fla

tnes

s of

this

are

a. L

ilius

is

larg

e en

ough

(61

km

) to

hav

e a

cent

ral

peak

like

tha

t of

Tyc

ho. C

entr

al p

eaks

occ

ur i

n cr

ater

s w

ith

diam

eter

s in

the

rang

e of

20

to 2

00 k

m.

LO4-

112H

1Su

n El

evat

ion:

20.

4°A

ltit

ude:

298

6.04

km

91

Hum

oru

mBa

sin R

egio

n

Soft

ray

pat

tern

s an

d ch

ains

of

very

sm

all s

econ

dary

cra

ters

radi

ate

from

Tyc

ho ju

st to

the

wes

t of t

his

pict

ure.

Cha

ins

ofel

onga

te lo

w-a

ngle

-of-

inci

denc

e cr

ater

s be

twee

n N

asir

eddi

nan

d Li

cetu

s co

uld

have

com

e ov

er t

he S

outh

Pol

e fr

om t

heSc

hrod

inge

r B

asin

. T

hey

coul

d al

so h

ave

com

e fr

om t

heso

uthw

este

rn s

ecto

r of

Im

briu

m.

It i

s in

tere

stin

g to

stu

dy

the

sequ

ence

of

the

clus

ter

of la

rge

crat

ers

in t

he u

pper

hal

fof

thi

s pi

ctur

e. N

asir

eddi

n ha

s cl

earl

y im

pact

ed a

nd c

ol-

laps

ed t

he w

alls

of

Hug

gins

and

Mil

ler;

Hug

gins

has

col

-la

psed

the

wal

l of

Oro

ntiu

s. S

auss

ure

seem

s yo

unge

r th

anO

ront

ius.

A c

rate

r ev

en o

lder

tha

n O

ront

ius

is r

epre

sent

edon

ly b

y pa

rt o

f its

rim

, jus

t to

the

east

of S

auss

ure.

92

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

112H

2Su

n El

evat

ion:

20.

4°A

ltit

ude:

298

6.04

km

The

lar

ge c

hain

of

seco

ndar

ies

from

the

Im

briu

m B

asin

betw

een

Pita

tus

and

Des

land

res

lies

on

the

inne

r ej

ecta

blan

ket o

f the

Nub

ium

Bas

in. E

ject

a fr

om th

e N

ubiu

m B

asin

appe

ars

to h

ave

erod

ed t

he w

alls

of

Des

land

res

and

de-

posi

ted

fluid

(m

olte

n or

frag

men

ted)

mat

eria

l on

the

floor

of

Hel

l an

d th

e sm

alle

r cr

ater

sou

th o

f H

ell.

How

ever

, th

epa

tter

n of

eje

cta

seem

s to

dis

appe

ar o

n th

e flo

or o

f Des

land

res.

The

cra

ter

abou

t 80

km

to

the

nort

heas

t of

Hel

l lo

oks

like

crat

ers

that

hav

e be

en fl

oode

d w

ith m

are

lava

, but

the

mat

eria

lis

muc

h lig

hter

tha

n m

are.

The

wal

ls o

f th

e D

esla

ndre

s de

-pr

essi

on c

an b

e se

en a

s sq

uare

, ra

ther

tha

n ro

und.

Is

the

Des

land

res

depr

essi

on a

n im

pact

cra

ter

or t

he r

esul

t of

tec

-to

nic

forc

es p

rodu

cing

upl

ift

and

sink

ing?

Cou

ld t

ecto

nic

shak

ing

have

res

urfa

ced

the

smoo

th p

art

of t

he fl

oor

ofD

esla

ndre

s?

LO4-

112H

3Su

n El

evat

ion:

20.

4°A

ltit

ude:

298

6.04

km

93

Hum

oru

mBa

sin R

egio

n

Lalande has a spectacular ejecta patternbecause it impacted an area with in-herently light-colored material and de-posited it on the dark surface of MareInsularum. The deep troughs to thesoutheast of Lalande and radial to it aretoo large to be caused by Lalande andare from the Imbrium Basin.

An ancient 160-km flooded cratermay underlie the mare surface in thecenter of this picture. PromontoriumTaenarium could be a remainder of therim of this crater, associated with theintersection between that rim and a ringof the Nubium Basin. The mountainnorthwest of Lassell would be the top ofa complex central peak of the 160-kmflooded crater.

Rupes Recta (straight wall) is hard toexplain. It is not curved like the scarpson the inside of basin rings, and it doesnot appear to be directly related to theshore of Mare Nubium. It may be acontinuation of the degraded scarp nearDeslandres. Albedo patterns on theeastern border of Mare Nubium are alsounusual. Perhaps this is dark mantlingmaterial, pyroclastic fountain materialthat occurs near mare borders andspreads ballistically beyond the mare.

94

Luna

r O

rbiter

Photo

gra

phic

Atla

s

Stofl

er is

one

of m

any

larg

e cr

ater

s w

hose

floo

r is

rem

arka

bly

flat

and

smoo

th, a

ter

rain

typ

e th

at h

as b

een

calle

d “s

moo

thte

rra

plai

ns.”

The

floo

r ap

pear

s to

be

youn

ger

than

the

crat

erri

m, w

hich

sho

ws

degr

adat

ion.

One

exp

lana

tion

of

smoo

thte

rra

plai

ns i

s th

at t

hey

are

flat

surf

aces

tha

t ha

ve b

een

cove

red

by t

he o

uter

(sm

ooth

er)

type

of

basi

n ej

ecta

. T

his

type

of e

ject

a st

arts

at l

east

one

rad

ius

away

from

the

basi

n’s

topo

grap

hic

ring

and

usu

ally

end

s be

twee

n tw

o an

d th

ree

radi

i aw

ay. T

o ha

ve t

his

type

of

terr

ain,

a fl

at-fl

oore

d cr

ater

mus

t be

wit

hin

thre

e ra

dii

of s

ome

subs

eque

nt b

asin

and

mus

t no

t be

wit

hin

one

radi

us o

f an

y su

bseq

uent

bas

in.

Furt

her,

the

cra

ter

mus

t no

t ha

ve b

een

flood

ed w

ith

mar

ela

va o

r su

ffer

ed s

ome

othe

r ev

ent t

hat s

erio

usly

dis

rupt

ed it

sflo

or. T

ecto

nic

shak

ing

may

fur

ther

sm

ooth

and

flat

ten

sur-

face

s w

ith

such

dep

osit

s.

LO4-

107H

2Su

n El

evat

ion:

21.

6°A

ltit

ude:

298

1.85

km

95

Hum

oru

mBa

sin R

egio

n

Her

e is

a c

lust

er o

f cra

ters

, all

of s

imila

r si

ze (

70 to

140

km

),th

at a

re c

lust

ered

tog

ethe

r. T

heir

age

s va

ry, b

ut a

ll pr

obab

lyfo

llow

ed t

he N

ubiu

m B

asin

eve

nt. T

heir

cen

ters

are

wit

hin

120

km o

f a

cent

ral

poin

t, in

uni

form

tar

get

mat

eria

l. T

heov

erla

ppin

g ej

ecta

fro

m t

he t

hese

cra

ters

res

ulte

d in

the

chao

tic

inte

rcra

ter

area

s, w

ith

rim

s im

ping

ing

on e

ach

othe

ran

d m

ater

ial

pilin

g up

bet

wee

n an

d so

met

imes

wit

hin

the

crat

ers.

Sub

sequ

entl

y, t

he I

mbr

ium

Bas

in e

vent

has

de-

posi

ted

a un

ifor

m la

yer

of m

ater

ial t

hat h

as s

moo

thed

pre

vi-

ousl

y un

dist

urbe

d pa

rts

of t

he c

rate

r flo

ors.

Im

briu

m a

lso

drop

ped

a fe

w s

econ

dari

es h

ere.

Wer

ner

arri

ved

late

r; i

tsflo

or h

as n

ot b

een

smoo

thed

. Fin

ally

, Tyc

ho h

as d

ropp

ed it

sra

ys o

ver

the

clus

ter.

96

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

107H

3Su

n El

evat

ion:

21.

6°A

ltit

ude:

298

1.85

km

The

bit

(Lat

e Im

briu

m)

and

Wer

ner

(Era

tost

heni

an)

are

free

from

evi

denc

e of

sm

ooth

ter

ra p

lain

s an

d Im

briu

m s

econ

-da

ries

and

exh

ibit

lit

tle

rim

ero

sion

. O

n th

e ot

her

hand

,Pu

rbac

h, R

egio

mon

tanu

s, D

esla

ndre

s, a

nd L

a C

aille

(Pr

e-N

ecta

rian

) sh

ow s

moo

th t

erra

pla

ins

unit

s an

d so

me

seco

n-da

ries

, bot

h fr

om th

e Im

briu

m e

vent

.

LO4-

108H

1Su

n El

evat

ion:

21.

1°A

ltit

ude:

271

9.01

km

97

Hum

oru

mBa

sin R

egio

n

The

rim

s of

Pto

lem

aeus

and

Alp

hons

us s

how

str

iati

ons

from

the

Imbr

ium

Bas

in, b

ut t

he e

ffec

ts o

n th

eir

floor

s ha

ve b

een

all

or p

artl

y er

ased

by

lava

flow

s th

at h

ave

redu

ced

the

dept

hs o

f th

ese

crat

ers.

The

se c

rate

rs s

how

an

unus

ual h

igh

leve

l of

tho

rium

in

Luna

r Pr

ospe

ctor

dat

a. C

lem

enti

neal

bedo

dat

a sh

ow P

tole

mae

us t

o be

dar

k, b

ut n

ot a

s da

rk a

sne

arby

Oce

anus

Pro

cella

rum

and

Sin

us M

edii.

The

cra

ters

wit

h da

rk h

alos

in A

lpho

nsus

may

be

sour

ces

of fo

unta

ins

ofda

rk g

lass

bea

ds. R

ange

r 9

phot

os s

how

ed t

hat

part

s of

the

floor

of

Alp

hons

us w

ere

smoo

th li

ke m

are

surf

aces

at

scal

essi

gnifi

cant

for

land

ing

and

surf

ace

oper

atio

ns.

98

Luna

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

108H

2Su

n El

evat

ion:

21.

1°A

ltit

ude:

271

9.01

km

The

Apo

llo p

rogr

am w

as v

ery

inte

rest

ed i

n Si

nus

Med

ii(“

Cen

tral

Bay

”) a

s a

land

ing

site

bec

ause

its

cent

ral p

osit

ion,

rela

tive

to

mar

e si

tes

to t

he e

ast

and

wes

t, pr

ovid

ed a

ddi-

tion

al la

unch

win

dow

opp

ortu

niti

es. S

urve

yor

4 fa

iled

befo

reto

uchd

own,

but

Sur

veyo

r 6

land

ed s

ucce

ssfu

lly (

Nov

embe

r19

67).

Its

alp

ha-s

catt

erin

g in

stru

men

t co

nfirm

ed r

esul

tsfr

om t

hat

of S

urve

yor

5, s

how

ing

that

the

ele

men

t co

mpo

si-

tion

of

mar

e su

rfac

es c

orre

spon

ded

to t

he b

road

ran

ge o

fro

ck t

ypes

cal

led

basa

lt.

Thi

s im

plie

d th

at a

t le

ast

a m

ajor

port

ion

of t

he M

oon

had

unde

rgon

e a

mel

t ph

ase

that

sup

-po

rted

dif

fere

ntia

tion

of

min

eral

s. S

inus

Med

ii is

not

lar

geen

ough

to b

e a

basi

n; it

is a

cra

ter

that

has

bee

n flo

oded

wit

hla

va. I

t m

ay b

e in

fluen

ced

by t

he s

econ

d ex

tern

al t

roug

h of

the

Imbr

ium

Bas

in,

the

sam

e tr

ough

tha

t un

derl

ies

Mar

eFr

igor

is.

LO4-

108H

3Su

n El

evat

ion:

21.

1°A

ltit

ude:

271

9.01

km

99

Hum

oru

mBa

sin R

egio

n

10

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

7.1. OverviewThe Imbrium Basin Region includes a number of interestingfeatures such as Oceanus Procellarum, Copernicus, Kepler,the Aristarchus plateau, and Vallis Schroteri (Schroter’sValley) as well as Mare Imbrium, the Fra Mauro Formationof Imbrium ejecta, and surrounding maria. Because thesefeatures are so large, yet closely related, the region stretchesfrom the western edge of the visible Moon to the centralmeridian and from the equator to 60° north.

The Imbrium BasinThe Imbrium Basin (Figure 7.1) has had a larger influence onthe current appearance of the near side surface of the Moonthan any other single feature. Although mare flooding hidesmuch of the structure of Imbrium, enough remains to associ-ate its major features with those of Orientale and otherbasins. Specifically, the basin has an inner circular depressedfloor, largely flooded with mare. A scarped rim bounds thisdepression, and beyond the rim is a trough and then addi-tional raised rings. Flooding by surrounding mare has ob-scured much of the ejecta blanket except for the southeastsector. Here the Fra Mauro Formation can be seen to besimilar to the Hevelius Formation of the Orientale Basin.Chains of secondary craters that radiate from the central partof the Imbrium Basin extend beyond this region nearly to theeastern limb.

When the mountain ranges that form the topographic ringof the Imbrium Basin were named, they were not perceivedto be parts of a continuous circle; the sectors of the ring were given the names of familiar mountain ranges on Earth.Clockwise from the north they are Montes Alpes (Alps,France, Switzerland, and Italy), Montes Caucasus (Caucasus,Georgia), Montes Apenninus (Apennines, Italy), MontesCarpatus (Carpathians, Romania), and Montes Jura (JuraMountains, Switzerland, France).

Oceanus ProcellarumOceanus Procellarum (Figure 7.2) contains the largest dis-tinctly named area of mare on the Moon. It has often beenconsidered as evidence of a possible enormous ancient basin,the Procellarum Basin, perhaps three times the size of theImbrium Basin and underlying that basin as well as OceanusProcellarum. This hypothesis is supported by the determina-tion that the crust under this area is thinner than in the rest

of the Moon, perhaps caused by the removal of the top layerof crust by the massive impact. Additional evidence of theuniqueness of this region is provided by remote sensing, andby sample collection, which shows the region to be rich inKREEP minerals and thorium.

However, there are problems with that hypothesis. In par-ticular, there is little sign of massive radial ridges and troughsof an ejecta blanket or external rings that would be expectedto accompany such a large basin. Also, there are positive fea-tures (mountains) that protrude from the mare that are hardto reconcile with a large, flat central floor, even allowing for

Chapter 7

Imbrium Basin Region

Figure 7.1. LO4-134M. The inner edge of the topographic ring of theImbrium Basin is shown as a dashed circle, actually an ellipse here becausethe center of the photo does not coincide with the center of the basin.Within this ring, most of the area is covered with mare material (MareImbrium). Beyond this ring is a trough partly filled with mare (Mare Frigoristo the north and Mare Insularum and Mare Vaporum to the south). Thediameter of the topographic rim is 1160 km.

internal rings. It has also been suggested that OceanusProcellarum is an outer trough of the Imbrium Basin. If so, it is an extraordinarily large area of mare to fill a trough.

Examination of elevation data from Clementine andearlier spacecraft missions suggests a third explanation ofOceanus Procellarum. Mare lava shrinks as it cools, leavingdepressions where it is deepest. Roughly circular depressionssuggest multiple basin-sized depressions beneath OceanusProcellarum (McEwen, 1994). Supporting evidence of thedepth of the flooded depressions has come from analysis ofpartially flooded crater rims (De Hon, 1979). Further, arcs oftwo circular rims can be seen in the northern part of thismare (Figure 7.3).

The proposed Lavoissier-Mairan and Cardanus-HerodotusBasins have influenced the formation of two plateaus, whichhelp in determining the basin sizes and locations. The plateauwest of the Montes Jura (Jura Mountains) was formed byejecta from the proposed Lavoissier-Mairan Basin, theImbrium Basin, and a large crater under Sinus Roris. TheAristarchus plateau may have been built up by the easternintersection of the main rings of these two proposed basins(Byrne, 2004). Analysis of data from Lunar Prospector hasrevealed patches of high-thorium material surrounding theseproposed basins, especially the northern one (Gasnault,2002).

A similar examination of the topography of the southernpart of Oceanus Procellarum (Figure 7.4) shows a depressionthat may reveal a basin. In this case, the lava has left exposedremnants of crater rims and perhaps part of a complexcentral peak or inner ring. There are indications that a basin

in this area could be south of the position shown in Figure7.4 (the possible Flamsteed-Billy Basin of Wilhelms, 1987),but striations beyond the mare to the southwest are a betterfit to the location shown. Clementine data show a distinctlyhigher elevation of the mare floor between the Cardanus-Herodotus Basin shown in Figure 7.3 and the Reiner-Letronne Basin in Figure 7.4.

The possible existence of these basins does not refute thecontribution of an outer trough of the Imbrium Basin to the depression beneath the northeastern part of OceanusProcellarum. Nor do these basins in themselves explain thethinness of the crust and the unusual distribution of ra-dioactive, rare earth, and related elements (KREEP) in thispart of the Moon. This leaves room for the ProcellarumBasin hypothesis, so long as the basin formed when thecrust and early mantle were still soft enough for isostaticadjustment.

Fra Mauro FormationAt one time the Fra Mauro Formation was thought to containnumerous volcanic features, but other geologists believed it to be ejecta from the Imbrium Basin. The formation is so widespread that dating the Imbrium impact helps estab-lish ages of many other features. Analysis of samples fromApollo 14 (Humorum Basin Region) and Apollo 16 (NectarisBasin Region) established that this formation was depositedfrom the Imbrium Basin impact. See the chapters for theseregions for further discussion of these Apollo landings and

Figure 7.2. LO4-162M. The large dark area in this picture is OceanusProcellarum. Mare Imbrium is in the upper right part of the picture. Thebright-rayed craters are Aristarchus and Kepler (below and to the right ofAristarchus). The Grimaldi Basin is to the lower left of Oceanus Procellarumand the Humorum Basin is to the lower right.

Figure 7.3. LO4-175M. These two possible basins, called here theLavoissier-Mairan Basin (to the north) and the Cardanus-Herodotus Basin(each named after craters near their proposed main rings) are inferred fromcircular depressions revealed in Clementine elevation data. These basinsmay have attracted the lava that flooded the northern part of OceanusProcellarum.

10

1Im

bri

um

Ba

sin R

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10

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their contributions to our understanding of the ImbriumBasin.

7.2. High-Resolution ImagesTable 7.1 shows the high-resolution images of the ImbriumBasin Region in schematic form.

The following pages show the high-resolution subframesfrom south to north and west to east. That is, they are in the

order LO4-189H1, LO4-189H2, LO4-189H3, LO4-183H1,LO4-183H2 … LO4-162H1, LO4-162H2… LO4-110H3.

High-resolution photos of Mission 4 did not cover theextreme northwestern part of this region. Therefore, the firstphoto in this chapter is LO4-189M, which completes the nearside coverage in this area.

Subframes LO4-183H3, LO4-170H3, LO4-158H3, LO4-145H3, LO4-134H3, LO4-122H3, and LO4-110H3 have notbeen printed because of redundancy but are in the enclosedCD. The subframes of LO4-152, LO4-144, LO4-138, LO4-121,and LO4-114 have been merged into full frames.

Figure 7.4. Part of LO4-162M. The dashed circle outlines a possible basin, the Reiner-Letronne Basin that is inferred from a depression in Clementineelevation data. This basin may have attracted the lava that flooded the southern part of Oceanus Procellarum. The Grimaldi Basin is to the west and theHumorum Basin is to the southeast. The southeastern part of this possible basin is in the Orientale Basin Region and the southeast part is in the HumorumBasin Region.

Lattitude Range Photo Number

56 N–90 N 190 176 164 152 140 128 116 104

27 N–56 N 189 183 175 170 163 158 151 145 139 134 127 122 115 110 103

0–27 N 188 182 174 169 162 157 150 144 138 133 126 121 114 109 102

0–27 S 195 187 181 173 168 161 156 149 143 137 132 125 120 113 108 101

Longitude 89 W 82 W 76 W 68 W 62 W 56 W 49 W 41 W 35 W 30 W 23 W 16 W 10 W 3 W 4 E at Equator

Table 7.1. The cells shown in white represent the high-resolution photos of the Imbrium Region (LO4-XXX H1, -H2, and -H3, where XXX is the PhotoNumber). The Orientale Basin Region is to the southwest, the Humorum Basin Region is to the south, the Eastern Basins Region is to the east, and the NorthPolar Region is to the north.

Thi

s m

ediu

m-r

esol

utio

n ph

oto

is p

rovi

ded

to fi

ll in

fea

ture

s in

the

wes

tern

limb

area

of

the

Imbr

ium

Bas

in R

egio

n (a

nd s

ome

of t

he a

djoi

ning

far

sid

e)th

at w

ere

not

phot

ogra

phed

in

high

res

olut

ion.

The

lim

b ar

ea f

rom

Vol

tano

rth

is b

ette

r se

en i

n LO

4-19

0M,

show

n in

the

Nor

th P

olar

Reg

ion.

The

Ori

enta

le B

asin

ext

ends

its

eje

cta

blan

ket

and

seco

ndar

ies

beyo

nd E

inst

ein.

The

ray

s in

nor

ther

n O

cean

us P

roce

llaru

m c

ome

from

Har

palu

s, s

outh

of

Pyth

agor

as in

the

Nor

th P

olar

Reg

ion.

LO4-

188M

Sun

Elev

atio

n: 1

4.5°

Alt

itud

e: 3

645.

75 k

m

10

3Im

bri

um

Ba

sin R

egio

n

Striations on and within the rims of Repsold, Gerard, von Braun, andLavoisier may have come from the pos-sible Lavoissier-Mairan Basin. The east-west ridges and valleys northeast ofRepsold may be ejecta from a craterunder the nearby bay of OceanusProcellarum. In the 50-km crater west ofvon Braun, there is a moat of lavaaround the inside of the rim.

The bulging floors of these craters areheavily fractured, probably caused bytensile failure of the floor material, amelt sheet, as it is forced to expand. Thefractures on the floor of Repsold crosscrater rims without deflection; they areresponses to deep stress.

The eastern edge of Oceanus Pro-cellarum shows a thinning layer ofmare, leaving many crater rims. Somecraters such as Aston and Voskesenkiyare internally flooded with mare, whichmust have come from below. Thedegraded 55-km crater southeast ofVoskesenkiy shows striations that mayhave come from the possible basin innorthern Oceanus Procellarum.

10

4Lu

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s

Thi

s ph

oto

show

s th

e tr

ansi

tion

bet

wee

n th

e hi

ghla

nd r

egio

nto

the

wes

t, th

roug

h th

e sh

allo

w m

are

part

ly fl

oodi

ng c

rate

rs,

to v

ery

deep

mar

e. T

he d

eep

mar

e co

mpl

etel

y co

vers

lar

gecr

ater

s an

d pe

rhap

s ev

en a

n en

tire

bas

in.

LO4-

183H

1Su

n El

evat

ion:

19.

8°A

ltit

ude:

287

4.59

km

10

5Im

bri

um

Ba

sin R

egio

n

The

hig

hlan

d ar

ea e

ast o

f von

Bra

un il

lust

rate

s ho

w c

ompl

exto

pogr

aphy

can

be

scul

pted

by

a se

ries

of

circ

ular

cra

ters

,pa

rtly

floo

ded

wit

h m

are.

The

mat

eria

l in

the

wes

tern

hal

f of

the

floor

of

von

Bra

un c

ould

be

ejec

ta f

rom

the

pos

sibl

eba

sin

bene

ath

nort

hern

Oce

anus

Pro

cella

rum

. Str

iati

ons

inth

e ri

m o

f th

e 90

-km

floo

ded

crat

er n

orth

of

von

Bra

un a

ndin

the

resi

dual

hig

hlan

d m

ater

ial i

n th

e up

per

left

cor

ner

are

esse

ntia

lly r

adia

l to

that

pos

sibl

e ba

sin.

LO4-

183H

2Su

n El

evat

ion:

19.

8°A

ltit

ude:

287

4.59

km

10

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The field of sharp secondaries south ofOenopides and Babbage was depositedfrom the Eratosthenian crater Pytha-goras. Later in the Eratosthenian Perioda fresh lava flow south and west ofMarkov submerged parts of the sec-ondary field. A deep trough and ridgepattern runs about 15 km south fromMarkov. It may be ejecta from thepossible basin under northern OceanusProcellarum.

Rays from a crater on the north rimof Oenopides intersect with rays fromLichtenberg; this cloudy appearancehelped give Oceanus Procellarum itsname (“Ocean of Storms”). The darkstreak running east to west, passing justsouth of Lichtenberg, is one of the latestflows of lava in the maria. It covers raysand ejecta of the bright-rayed craterLichtenberg. Although very few lavaflows have taken place after the Era-tosthenian Period, this particular flowhas taken place in the CopernicanPeriod, which began on the order of 1 billion years ago. Nearly all mare sur-faces formed during the earlier LateImbrian Epoch and the EratosthenianPeriod. 1

07

Imb

rium

Ba

sin R

egio

n

The

dar

k yo

ung

lava

flow

tha

t co

vers

the

ray

s an

d ej

ecta

from

the

Cop

erni

can

crat

er L

icht

enbe

rg (

see

note

for

LO

4-17

5H)

cont

inue

s to

the

eas

t, w

here

it

is i

n tu

rn c

over

ed b

yra

ys f

rom

the

sm

all

crat

er n

ear

Dor

sum

Sci

lla.

Nei

ther

Dor

sum

Sci

lla n

or t

he w

rink

le r

idge

nea

r Li

chte

nber

gim

pede

d th

e da

rk fl

ow, w

hich

sug

gest

s th

at t

hey

may

hav

efo

rmed

aft

er th

e flo

w, p

erha

ps a

s it

coo

led.

LO4-

170H

1Su

n El

evat

ion:

19.

8°A

ltit

ude:

287

0.64

km

10

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Seve

ral

wri

nkle

rid

ges

mee

t at

Mon

s R

umke

r, w

hich

is

form

ed o

f mul

tipl

e ro

und

dom

es. P

erha

ps c

ontr

acti

on o

f the

cool

ing,

sol

idif

ying

mar

e su

rfac

e ca

used

lava

to

be e

xtru

ded

in t

his

area

a m

ulti

ple

num

ber

of t

imes

, ult

imat

ely

form

ing

Mon

s R

umke

r. I

f th

e la

va h

ere

was

of

a di

ffer

ent

chem

ical

com

posi

tion

or

cool

er t

han

the

usua

l m

are

mat

eria

l, it

svi

scos

ity

may

hav

e be

en g

reat

er, a

llow

ing

the

prom

inen

ce to

build

up.

LO4-

170H

2Su

n El

evat

ion:

19.

8°A

ltit

ude:

287

0.64

km

10

9Im

bri

um

Ba

sin R

egio

n

These spectacular bright rays radiatefrom the Copernican crater Glusko, farto the southwest (L04-174H1 and -H2,in the Orientale Basin Region). Wrinkleridges are major topographic features ofthis area of deep mare, probably formedto relieve compression stresses as lavasubsided under a hardening surface.

Luna 8 (1965) was nearly successfulbut fired its retro-rocket a bit late andwas destroyed by an excessively hardlanding.

Luna 9 was fully successful, the firstspacecraft to land beyond Earth. Itscamera viewed the surrounding area,named Planitia Descensus (Plain ofDescent).

Rimae Hevelius reveal fractures thatare radial and circumferential to therounded edge of the mare. The densemare material makes the surroundingareas bend inward toward the mare,inducing tensional forces that are re-lieved by V-shaped fractures (whosewidth is greatest where the surface ele-vation is highest). Striations in the rimof Hevelius and the area southeast ofLohrman are radial to the OrientaleBasin, about one radius away from therim of that basin. This is the “type area”of the Hevelius Formation (ejecta fromOrientale).

11

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The

mar

e ri

dges

sho

wn

here

giv

e th

e im

pres

sion

of b

reak

ing

wav

es i

n a

larg

e bo

dy o

f flu

id.

Thi

s m

ay b

e as

muc

h an

anal

ogy

as a

met

apho

r be

caus

e th

ey w

ere

poss

ibly

form

ed b

yco

mpr

essi

on f

ract

urin

g of

the

har

deni

ng s

urfa

ce o

f a

fluid

ocea

n of

lava

. Suc

h fr

actu

res

wou

ld n

ot h

ave

been

sim

ulta

ne-

ous:

eac

h fr

actu

re w

ould

rel

ieve

str

ess

for

a ti

me

unti

l it

agai

n bu

ilt u

p. A

n in

divi

dual

fra

ctur

e m

ight

be

unlik

ely

tobr

eak

a se

cond

tim

e be

caus

e it

wou

ld a

ctua

lly b

e a

thic

ker,

stro

nger

par

t of t

he s

urfa

ce a

fter

coo

ling,

esp

ecia

lly if

the

un-

derl

ying

lava

mel

t wel

ded

the

frac

ture

d m

ater

ial t

oget

her.

LO4-

163H

1Su

n El

evat

ion:

20.

1°A

ltit

ude:

286

6.72

km

11

1Im

bri

um

Ba

sin R

egio

n

Rim

a Sh

arp

is s

inuo

us,

unli

ke o

ther

rim

ae t

hat

are

mor

elin

ear.

Alth

ough

line

ar r

imae

are

inte

rpre

ted

as s

urfa

ce m

an-

ifes

tati

ons

of f

ract

ures

tha

t re

lieve

ten

sion

, si

nuou

s ri

mae

(rill

es)

are

inte

rpre

ted

as th

e re

sult

of fl

ows

of fl

uid

alon

g lo

wsl

opes

. On

Eart

h, t

he m

ost

fam

iliar

ana

logy

is t

hat

of m

ean-

deri

ng s

trea

ms

and

rive

rs fl

owin

g in

allu

vial

val

leys

. T

hecu

rvin

g an

d re

curv

ing

mea

nder

s ar

e dy

nam

ical

ly c

ause

d by

late

ral

osci

llati

ons

of t

he m

omen

tum

of

a m

ovin

g flu

id,

whi

ch i

s pr

obab

ly l

ow-v

isco

sity

lav

a on

the

Moo

n. S

uch

mea

nder

s m

ay h

ave

been

ver

y co

mm

on d

urin

g fil

ling

of t

hem

are,

but

per

haps

onl

y th

ose

asso

ciat

ed w

ith

the

last

flow

sha

ve s

urvi

ved

bein

g su

bmer

ged.

LO4-

163H

2Su

n El

evat

ion:

20.

1°A

ltit

ude:

286

6.72

km

11

2Lu

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Photo

gra

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Atla

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Thi

s is

the

wid

est

part

of

Rim

a Sh

arp,

and

is

prob

ably

the

sour

ce o

f it

s flo

w (

see

LO4-

163H

2). A

t it

s no

rthe

rn e

xtre

me,

it a

ctua

lly b

reak

s in

to r

elat

ivel

y sm

alle

r tr

ibut

arie

s, a

ppar

-en

tly

gath

erin

g la

va b

efor

e ca

rryi

ng i

t so

uthw

ard.

Per

haps

lava

upw

elli

ng i

nto

the

area

sou

thw

est

of H

arpa

lus

was

bloc

ked

by t

he h

ighl

and

prom

inen

ce i

n th

e lo

wer

rig

htco

rner

of

the

phot

o (p

art

of t

he r

im r

ing

of t

he I

mbr

ium

Bas

in)

and

form

ed R

ima

Shar

p as

it fo

und

a ro

ute

to a

low

erel

evat

ion.

The

hig

hly

erod

ed c

rate

r So

uth

is c

over

ed w

ith

Fra

Mau

ro F

orm

atio

n, e

ject

a fr

om th

e Im

briu

m B

asin

. Har

palu

sis

a C

oper

nica

n cr

ater

wit

h a

broa

d ra

y pa

tter

n.

LO4-

163H

3Su

n El

evat

ion:

20.

1°A

ltit

ude:

286

6.72

km

11

3Im

bri

um

Ba

sin R

egio

n

Rei

ner

Gam

ma

is a

ver

y un

usua

l fe

atur

e. T

he I

AU

cla

ssifi

es i

t as

an

albe

dofe

atur

e, t

o fin

esse

the

que

stio

n of

its

orig

in a

s an

impa

ct o

r in

tern

al p

roce

ss.

Alt

houg

h ra

re, t

here

are

a f

ew o

ther

fea

ture

s w

ith

sim

ilar

brig

ht s

wir

ls. T

hey

occu

r in

are

as w

ith

mag

neti

c an

omal

ies.

It

has

been

sug

gest

ed t

hat

the

mag

-

neti

c fie

lds

defle

ct t

he i

oniz

ed s

olar

win

d. W

itho

ut s

uch

prot

ecti

on, i

oniz

edhy

drog

en (

prot

ons)

red

uces

oxi

des

in t

he s

urfa

ce g

rain

s, f

reei

ng e

lem

enta

lir

on. T

he ir

on a

bsor

bs li

ght,

dark

enin

g th

e su

rfac

e. W

hat c

ause

s th

e m

agne

tic

anom

alie

s is

unk

now

n.

LO4-

157H

1Su

n El

evat

ion:

16.

9°A

ltit

ude:

266

8.85

km

11

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

Mar

ius

Hill

s ha

ve b

een

inte

rpre

ted

as a

vol

cani

cally

act

ive

regi

on. R

ima

Gal

ilaei

see

ms

to h

ave

colle

cted

and

tran

spor

ted

lava

from

two

trib

utar

ies

near

its

sout

heas

t en

d. O

ther

rim

ae i

n th

e ar

ea s

eem

to

star

t at

cra

ters

tha

t m

ayha

ve f

orm

ed a

roun

d an

und

ergr

ound

sou

rce

of la

va. T

he n

orth

ern

boun

dary

of t

he e

leva

ted

hilly

ter

rain

occ

urs

alon

g th

e ri

ng o

f th

e pr

opos

ed L

avoi

ssie

r-

Mai

ran

Bas

in,

so i

t m

ay b

e an

eje

cta

blan

ket

of t

hat

basi

n. I

f so

, th

e ej

ecta

wou

ld h

ave

been

mod

ified

by

flood

ing

wit

h la

va fr

om b

elow

, filli

ng a

ny r

adia

ltr

ough

s. A

s in

man

y ca

ses

whe

re th

in la

va c

omes

in c

onta

ct w

ith

high

land

ma-

teri

al, t

he a

rea

may

hav

e be

en c

over

ed w

ith

dark

man

tlin

g m

ater

ial,

gene

rate

dby

foun

tain

s of

gla

ss b

eads

.

LO4-

157H

2Su

n El

evat

ion:

16.

9°A

ltit

ude:

266

8.85

km

11

5Im

bri

um

Ba

sin R

egio

n

The

hig

hlan

d ar

ea in

the

uppe

r ri

ght q

uadr

ant o

f thi

s ph

oto

is th

e ea

ster

n ha

lfof

a l

arge

isl

and

in O

cean

us P

roce

llaru

m k

now

n as

the

Ari

star

chus

Pla

teau

.T

he e

aste

rn h

alf

can

be s

een

in L

O4-

150H

3. T

his

plat

eau

may

hav

e be

enfo

rmed

by

a tr

iple

inte

rsec

tion

of

ring

s; t

he fi

rst

exte

rnal

ele

vate

d ri

ng o

f th

e

Imbr

ium

Bas

in, t

he s

outh

east

ern

rim

of

the

Lavo

issi

er-M

aira

n ba

sin,

and

the

nort

heas

tern

rim

of

the

poss

ible

Car

danu

s-H

erod

otus

Bas

in. V

allis

Sch

rote

rise

ems

to b

e ca

rryi

ng l

ava

dow

n to

the

mar

e su

rfac

e. S

ee L

O4-

158H

1 an

d it

sno

tes

for

mor

e on

this

feat

ure.

LO4-

157H

3Su

n El

evat

ion:

16.

9°A

ltit

ude:

266

8.85

km

11

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

nor

thea

ster

n se

ctor

of

the

Ari

star

chus

pla

teau

(lo

wer

righ

t in

this

pho

to)

is r

ich

in e

vide

nce

of s

ubsu

rfac

e th

erm

al(e

ndot

herm

ic)

acti

vity

. M

ulti

ple

sinu

ous

rille

s ca

rry

lava

dow

n to

the

mar

e su

rfac

e fr

om s

ourc

e cr

ater

s. V

alli

sSc

hrot

eri

show

s ev

iden

ce o

f a

mas

sive

out

pour

ing

of l

ava

that

exc

avat

ed t

he v

alle

y, f

allin

g ne

arly

4 k

m f

rom

Cob

raH

ead,

the

sou

rce

crat

er,

to t

he m

are

surf

ace

140

km a

way

(LO

157H

3).

Pres

umab

ly t

he m

assi

ve A

rist

arch

us P

late

aubl

ocke

d up

wel

ling

of

mag

ma,

whi

ch w

as fi

nally

flow

ing

thro

ugh

Val

lis

Schr

oter

i, R

ima

Agr

icol

a,

and

Rim

aeA

rist

arch

us.

LO4-

158H

1Su

n El

evat

ion:

19.

6°A

ltit

ude:

286

5.60

km

11

7Im

bri

um

Ba

sin R

egio

n

LO4-

158H

2Su

n El

evat

ion:

19.

6°A

ltit

ude:

286

5.60

km

11

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s cu

rved

sho

relin

e of

Oce

anus

Pro

cella

rum

cou

ld b

e th

eri

m a

nd e

ject

a pa

tter

n of

the

pos

sibl

e La

vois

sier

-Mai

ran

Bas

in. S

ome

stri

atio

ns a

nd c

rate

r ch

ains

in

this

are

a ar

e in

the

appr

opri

ate

radi

al d

irec

tion

, no

rthw

est

to s

outh

east

,w

hile

oth

ers

radi

ate

from

the

Imbr

ium

Bas

in. T

his

area

may

be c

over

ed w

ith

two

laye

rs o

f ba

sin

ejec

ta b

lank

ets,

the

Fra

Mau

ro F

orm

atio

n be

ing

the

uppe

r la

yer.

The

ray

pas

sing

to

the

sout

h of

Sue

ss is

fro

m K

eple

r, t

o th

eea

st-n

orth

east

. Act

ually

, all

but t

he u

pper

and

low

er le

ft s

ides

of t

he a

rea

in t

his

imag

e ar

e lig

htly

cov

ered

wit

h K

eple

r ra

ym

ater

ial.

The

nea

rly

subm

erge

d cr

ater

s to

the

sout

h in

dica

teth

at th

e m

are

laye

r is

rel

ativ

ely

thin

ther

e, n

ear

the

sout

hern

edge

of O

cean

us P

roce

llaru

m.

LO4-

150H

1Su

n El

evat

ion:

17.

8°A

ltit

ude:

266

8.40

km

11

9Im

bri

um

Ba

sin R

egio

n

Thi

s is

the

eas

tern

edg

e of

the

Mar

ius

Hill

s (s

ee L

O4-

157H

2fo

r th

e w

este

rn e

dge)

. Lun

a 7

faile

d du

e to

pre

mat

ure

igni

-ti

on o

f its

ret

ro-r

ocke

t in

Oct

ober

196

5 an

d cr

ashe

d at

the

in-

dica

ted

site

. R

ima

Mar

ius

flow

s no

rth

into

the

mar

e flo

orfr

om th

e hi

lls w

hile

Rim

a Su

ess

flow

s do

wn

to th

e so

uth.

The

chai

ns o

f sm

all

crat

ers

to t

he e

ast

and

sout

heas

t of

Mar

ius

radi

ate

from

Kep

ler.

LO4-

150H

2Su

n El

evat

ion:

17.

8°A

ltit

ude:

266

8.40

km

12

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s is

the

eas

tern

par

t of

the

Ari

star

chus

Pla

teau

: th

ew

este

rn p

art

can

be s

een

in L

O4-

157H

3. C

oper

nica

n cr

ater

Ari

star

chus

, it

s ej

ecta

, an

d it

s ra

y pa

tter

n do

min

ate

this

phot

o. C

ount

s of

cra

ters

on

its

floor

sho

w A

rist

arch

us t

o be

very

you

ng, n

earl

y as

you

ng a

s T

ycho

. Cle

arly

, the

re h

as b

een

a gr

eat

deal

of

upw

elli

ng o

f la

va h

ere,

to

gene

rate

all

the

ridg

es a

nd la

va s

trea

ms.

Rem

ote

sens

ing

of th

e su

rfac

e of

this

area

sho

ws

a hi

gh p

erce

ntag

e of

REE

(ra

re e

arth

ele

men

ts),

whi

ch i

ndic

ate

radi

oact

ivit

y, b

ecau

se o

f hi

gh c

hem

ical

affin

ity

to th

e ur

aniu

m-t

hori

um s

erie

s. T

he L

unar

Pro

spec

tor

spac

ecra

ft c

onfir

med

a h

igh

leve

l of

tho

rium

. Rad

ioac

tivi

tyge

nera

tes

heat

and

the

hea

t ca

uses

the

mel

ting

roc

k to

expa

nd a

nd r

ise.

LO4-

150H

3Su

n El

evat

ion:

17.

8°A

ltit

ude:

266

8.40

km

12

1Im

bri

um

Ba

sin R

egio

n

The

nor

ther

n pa

rt o

f the

Ari

star

chus

Pla

teau

is s

how

n in

the

low

er h

alf

of t

his

phot

o. O

cean

us P

roce

llaru

m s

eem

s th

inhe

re, l

eavi

ng r

emna

nts

of o

lder

fea

ture

s su

ch a

s Pr

inz

and

Mon

tes

Har

bing

er p

roje

ctin

g ab

ove

the

mar

e flo

or. H

owev

er,

ther

e ar

e ex

tens

ive

sign

s of

lav

a flo

win

g ou

t fr

om v

ario

usso

urce

s on

the

Ari

star

chus

Pla

teau

and

run

ning

thro

ugh

the

rim

ae d

own

to t

he m

are

surf

ace.

Not

e th

at e

ach

rim

a se

ems

to s

tart

fro

m a

cra

ter.

The

Ari

star

chus

im

pact

or p

roba

bly

arri

ved

long

aft

er th

e er

upti

ons

ende

d.

LO4-

151H

1Su

n El

evat

ion:

20.

9°A

ltit

ude:

286

5.91

km

12

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Sinu

s Ir

idum

, a b

ay o

ff o

f Mar

e Im

briu

m, r

esul

ts fr

om a

cir

-cu

lar

impa

ct f

eatu

re w

hose

rim

dia

met

er o

f 26

0 km

res

ults

in i

t be

ing

char

acte

rize

d as

a c

rate

r ra

ther

tha

n as

a b

asin

.M

onte

s Ju

ra c

onst

itut

es t

he r

im o

f th

e Ir

idum

cra

ter.

The

chai

ns o

f se

cond

ary

crat

ers

and

othe

r li

neat

ions

in

this

pict

ure

tend

to

be r

adia

l to

Sin

us I

ridu

m,

rath

er t

han

toIm

briu

m,

indi

cati

ng t

hat

the

Irid

ium

cra

ter

occu

rred

lat

erth

an t

he I

mbr

ium

Bas

in.

Mon

s G

ruit

huis

en G

amm

a an

dD

elta

, wit

h a

crat

er o

n to

p of

eac

h of

them

, hav

e be

en c

onsi

d-er

ed t

o be

vol

cani

c, b

ut t

hey

may

sim

ply

be r

elic

s of

the

Imbr

ium

Bas

in,

mod

ified

by

the

Irid

um e

ject

a an

d co

inci

-de

ntal

pri

mar

y or

sec

onda

ry c

rate

rs a

t the

ir p

eaks

. The

re a

rese

vera

l suc

h fe

atur

es o

n th

e flo

or o

f Mai

ran.

LO4-

151H

2Su

n El

evat

ion:

20.

9°A

ltit

ude:

286

5.91

km

12

3Im

bri

um

Ba

sin R

egio

n

LO4-

151H

3Su

n El

evat

ion:

20.

9°A

ltit

ude:

286

5.91

km

12

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

nor

thw

este

rn r

im o

f th

e Im

briu

m B

asin

cro

sses

dia

-go

nally

acr

oss

this

pic

ture

. M

are

Frig

oris

has

floo

ded

the

oute

r tr

ough

of

the

Imbr

ium

Bas

in.T

he a

rea

betw

een

Sinu

sIr

idum

and

Mar

e Fr

igor

is h

as b

een

cris

scro

ssed

wit

h ej

ecta

from

dif

fere

nt d

irec

tion

s. S

tron

g so

uthe

ast

to n

orth

wes

tlin

eati

ons

from

the

dire

ctio

n of

the

Imbr

ium

Bas

in a

re c

lear

,as

are

line

atio

ns r

adia

l to

the

Irid

um c

rate

r.

This area just east of the Aristarchusplateau has relatively thin mare cover-age; it is higher than the central maresurfaces of either Oceanus Procellarumor Mare Imbrium. Numerous rilles (andthe lakes that fed them) carried lavafrom the vicinity of Prinz to the north.Montes Harbinger is probably a rem-nant of the topographic ring of theImbrium Basin.

Some of the valleys of Rimae Prinzare quite wide. Like meanderingstreams on Earth, some sinuous rilles oflava on the Moon are dynamic. In time,their individual bends move in a down-stream direction and sweep out a widevalley.

The rays from Kepler, coming from the southeast, meet rays fromAristarchus, coming from the north-west. Kepler is larger than Aristarchusbut is further away from the center ofthe picture. Note the pair of overlappingcraters near 7° N, 43° W (the larger of the overlapping craters is calledBessarion B). The unusually sharpseptum between the two suggests a si-multaneous impact of the two craters;neither has pushed wall material intothe other.

The flooded crater rims belowMaestlin show striations from theImbrium Basin.

12

5Im

bri

um

Ba

sin R

egio

n

Mon

s D

elis

le a

nd t

he a

rchi

pela

go o

f “i

slan

ds”

in t

he m

are

that

le

ad

to

Mon

s G

ruit

huis

en

Gam

ma

and

Mon

sG

ruit

huis

en D

elta

are

rem

nant

s of

the

mos

tly

subm

erge

dto

pogr

aphi

c ri

ng o

f the

Imbr

ium

Bas

in.

LO4-

145H

1Su

n El

evat

ion:

20.

7°A

ltit

ude:

286

8.12

km

12

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Prom

onto

rium

Her

aclid

es i

s a

resu

lt o

f th

e in

ters

ecti

on o

fth

e ri

m o

f the

cra

ter

unde

rlyi

ng S

inus

Irid

um (

Mon

tes

Jura

ispa

rt o

f tha

t ri

m)

and

the

high

est

ring

of t

he I

mbr

ium

Bas

in.

The

cur

ve a

t th

e so

uthe

rn b

orde

r of

the

pro

mon

tori

um(p

enin

sula

) is

not

the

cur

ve o

f th

e Im

briu

m r

im,

but

isfo

rmed

by

the

Irid

um c

rate

r pu

shin

g th

e Im

briu

m r

ing

and

floor

mat

eria

l out

war

d. T

he la

rge

vert

ical

rid

ge a

t the

bas

e of

the

peni

nsul

a is

mor

e re

pres

enta

tive

of

the

Imbr

ium

rin

g in

this

are

a. M

ost

of t

he h

eavy

eje

cta

terr

ain

on t

he l

eft

of t

hepi

ctur

e is

from

the

Irid

um e

vent

, but

trac

es o

f str

iati

ons

from

the

Imbr

ium

Fra

Mau

ro F

orm

atio

n (p

roba

bly

light

ly c

over

edby

Iri

dum

eje

cta

as w

ell)

can

be

seen

in th

e lo

wer

left

and

inth

e up

per

left

of t

he p

hoto

.

LO4-

145H

2Su

n El

evat

ion:

20.

7°A

ltit

ude:

286

8.12

km

12

7Im

bri

um

Ba

sin R

egio

n

Oceanus Procellarum meets MareImbrium (upper right) near MonsVinogradov, which is part of the highestring of the Imbrium Basin. The dark-ness of the mare surface, plus the pat-terns of Dorsum Aduino and the long,narrow Rima Brayley suggest a younglava flow of low viscosity. Rima Brayleyappears to guide lava in each directionaway from a low rise near craterBrayley.

The knobby terrain curving along theright side of this picture is part of a circular feature that bounds MareInsularum. The shapes of the interior ofKepler and its wall have been disruptedby the crater near its northern rim. Thisimpact, being younger than Kepler,must have added its ray pattern on topof the one from Kepler itself. Southwestof Kepler, projecting from the maresurface of Oceanus Procellarum, areridges and valleys radial to the ImbriumBasin. They are probably exposed be-cause they top the first circumferentialring of the Imbrium Basin outside of itshighest ring, the ring that bounds thetrough occupied by Mare Frigoris.

12

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

It is

dif

ficul

t to

assi

gn th

e ag

e of

Dio

phan

tus.

Sha

rpne

ss a

ndcr

ater

cou

nts

are

sim

ilar

to

thos

e ch

arac

teri

stic

s of

old

erC

oper

nica

n Pe

riod

cra

ters

. How

ever

, the

lack

of a

ray

pat

tern

has

resu

lted

in

assi

gnm

ent

to t

he p

revi

ous

Erat

osth

enia

nPe

riod

. The

pro

lifer

atio

n of

dor

sa (

mar

e ri

dges

), m

ostl

y ci

r-cu

mfe

rent

ial

to t

he I

mbr

ium

Bas

in,

refle

ct t

he s

tres

ses

ofm

assi

ve fl

ow a

nd s

ubse

quen

t coo

ling.

LO4-

139H

1Su

n El

evat

ion:

20.

2°A

ltit

ude:

287

2.43

km

12

9Im

bri

um

Ba

sin R

egio

n

The

pr

esen

ce

of

Sinu

s Ir

idum

, m

ore

clea

rly

seen

in

LO

4-14

5H2,

app

ears

to

have

str

ongl

y af

fect

ed t

he p

atte

rn o

fm

are

ridg

es i

n th

is a

rea.

Pro

mon

tori

um H

erac

lide

s an

dPr

omon

tori

um L

apla

ce m

ark

the

inte

rsec

tion

of

the

rim

of

the

crat

er t

hat

unde

rlie

s Si

nus

Irid

um w

ith

the

high

est

ring

of t

he I

mbr

ium

Bas

in. A

lar

ge u

nnam

ed m

are

ridg

e cu

rves

betw

een

thes

e tw

o pr

omon

tori

es a

nd m

ay m

ark

the

east

ern

and

sout

hern

rim

s of

the

crat

er b

enea

th S

inus

Irid

um.

LO4-

139H

2Su

n El

evat

ion:

20.

2°A

ltit

ude:

287

2.43

km

13

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Mon

tes

Rec

ti is

a p

art o

f the

mai

n ri

ng o

f the

Imbr

ium

Bas

in.

Mar

e la

va h

as p

enet

rate

d th

e ri

ng a

nd fl

oode

d pa

rt o

f th

eIm

briu

m e

ject

a bl

anke

t (F

ra M

auro

For

mat

ion,

cov

ered

by

ejec

ta fr

om th

e Ir

idum

cra

ter)

. Thi

s se

ctio

n of

Mar

e Fr

igor

isha

s flo

oded

the

tro

ugh

beyo

nd t

he m

ain

ring

. The

str

iati

ons

runn

ing

from

sou

thw

est

to n

orth

east

com

e fr

om t

he I

ridu

mcr

ater

and

hav

e ne

arly

(bu

t no

t en

tire

ly)

eras

ed t

he r

idge

san

d va

lleys

rad

iati

ng fr

om th

e in

teri

or o

f the

Imbr

ium

Bas

in.

The

re a

re s

tron

g ev

iden

ces

of fl

ow o

n th

e flo

or o

f Mau

pert

uis

and

Rim

ae M

aupe

rtui

s th

at m

ay h

ave

resu

lted

from

a d

epos

itof

mol

ten

ejec

ta fr

om th

e Si

nus

Irid

um c

rate

r.

LO4-

139H

3Su

n El

evat

ion:

20.

2°A

ltit

ude:

287

2.43

km

13

1Im

bri

um

Ba

sin R

egio

n

The

arc

of h

ills

larg

ely

subm

erge

d by

the

mar

e su

rfac

e, in

terp

rete

d as

isla

nds,

help

ed g

ive

Mar

e In

sula

rum

its

nam

e. T

his

curv

ed r

idge

of s

umm

its

may

rep

-re

sent

the

rim

of t

he p

ossi

ble

Insu

laru

m B

asin

und

erly

ing

Mar

e In

sula

rum

. A

clus

ter

of lo

w d

omes

, eac

h w

ith

a cr

ater

in it

s ce

nter

can

be

seen

nor

thea

st o

fH

orte

nsiu

s. T

hese

dom

es m

ay b

e th

e re

sult

of l

ava

extr

usio

ns. R

etre

atin

g la

vale

aves

a c

entr

al c

rate

r in

the

top

of th

e do

me,

a c

alde

ra.

LO4-

133H

1Su

n El

evat

ion:

18.

5°A

ltit

ude:

267

3.45

km

13

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

A l

ow 8

-km

dom

e w

ith

a ce

ntra

l cr

ater

or

cald

era

can

be s

een

abou

t 20

km

wes

t of

Mili

chiu

s. T

his

dom

e is

sur

roun

ded

by a

lava

flow

wit

h vi

sibl

e ed

ges

(sca

rps)

that

ext

end

to th

e ri

m o

f Mili

chiu

s. R

ima

T. M

ayer

has

bee

n de

flect

edar

ound

ano

ther

low

dom

e w

ith

a ce

ntra

l cra

ter.

Mon

tes

Car

patu

s is

par

t of t

heri

m o

f M

are

Imbr

ium

. T

he fl

oodi

ng o

f ev

ery

poss

ible

sm

all

inle

t al

ong

the

nort

hern

sho

re o

f th

e M

onte

s C

arpa

tus

illus

trat

es h

ow e

asily

the

lava

flow

ed.

The

vis

cosi

ty m

ust

have

bee

n m

uch

low

er t

han

typi

cal

terr

estr

ial

lava

, lo

wen

ough

to

over

com

e th

e ef

fect

of

low

er l

unar

gra

vity

(on

e-si

xth

of E

arth

’sgr

avit

y). T

he d

iffe

renc

e is

att

ribu

ted

to a

rel

ativ

e la

ck o

f vo

lati

le e

lem

ents

in

luna

r la

va.

LO4-

133H

2Su

n El

evat

ion:

18.

5°A

ltit

ude:

267

3.45

km

13

3Im

bri

um

Ba

sin R

egio

n

A v

ery

larg

e la

va fl

ow e

xten

ds f

rom

an

area

nor

th o

f Eu

ler

thro

ugh

the

gap

betw

een

Mon

s La

Hir

e an

d th

e hi

lls 3

0 km

to

the

nort

hwes

t, al

l th

e w

ay t

oD

orsu

m Z

irke

l. T

he e

dges

of t

his

flow

are

just

bar

ely

visi

ble

in th

is im

age

and

in L

O4-

126H

3, b

ut c

an b

e se

en m

ore

clea

rly

in A

pollo

15

fram

e M

-155

6, ta

ken

at a

low

er s

un a

ngle

.

LO4-

133H

3Su

n El

evat

ion:

18.

5°A

ltit

ude:

267

3.45

km

13

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Cra

ters

Cha

rles

, Mav

is, A

nneg

rit,

Ver

ne, a

nd F

elix

are

sm

all

crat

ers

that

wer

e gi

ven

spec

ial

atte

ntio

n be

caus

e th

ey w

ere

phot

ogra

phed

at

high

res

olut

ion

by o

rbit

ing

Apo

llo s

pace

-cr

aft.

The

offi

cial

IAU

nam

es o

f suc

h la

ndm

ark

crat

ers

are

all

“firs

t na

mes

” (p

erso

nal n

ames

from

a v

arie

ty o

f cul

ture

s) o

rin

a fe

w c

ases

the

nam

es o

f god

s an

d go

ddes

ses.

Thi

s pa

rtic

u-la

r ar

ea,

if c

hose

n as

a l

andi

ng s

ite,

wou

ld h

ave

allo

wed

surf

ace

expl

orat

ion

of d

isti

nctl

y di

ffer

ent l

ava

flow

s.

LO4-

134H

1Su

n El

evat

ion:

21.

4°A

ltit

ude:

287

8.51

km

13

5Im

bri

um

Ba

sin R

egio

n

Pair

s of

im

pact

cra

ters

wit

h ve

ry s

imil

ar s

izes

, ag

es,

and

othe

r ch

arac

teri

stic

s ar

e fo

und

on t

he M

oon

and

also

on

Eart

h. H

elic

on a

nd L

e V

erri

er a

re a

n ex

ampl

e of

suc

h a

pair

on t

he M

oon.

Rec

ent

mod

elin

g of

col

lisio

ns o

f K

uipe

r be

ltob

ject

s in

dica

tes

that

the

re i

s a

sign

ifica

nt p

opul

atio

n of

pair

s of

obj

ects

of s

imila

r si

ze th

at m

utua

lly o

rbit

eac

h ot

her.

Plut

o an

d C

haro

n ar

e th

e la

rges

t ex

ampl

e of

suc

h a

pair

, if

inde

ed t

hey

cam

e fr

om t

he K

uipe

r re

gion

. C

omet

s co

me

from

the

Kui

per

regi

on a

nd a

re a

n im

port

ant

com

pone

nt o

fpr

imar

y im

pact

ors

on th

e M

oon,

so

it is

ver

y re

ason

able

that

thes

e pa

irs

of c

rate

rs c

ome

from

pai

red

com

ets.

See

the

note

sfo

r LO

4-12

7H1

for

furt

her

disc

ussi

on o

f H

elic

on a

nd L

eV

erri

er.

LO4-

134H

2Su

n El

evat

ion:

21.

4°A

ltit

ude:

287

8.51

km

13

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Mas

sive

dep

osit

s fr

om C

oper

nicu

s co

ver

the

east

ern

rim

of

the

Insu

laru

m B

asin

, jus

t nor

thea

st o

f Rei

nhol

d. L

una

5 (M

ay19

65)

suff

ered

a b

ad m

idco

urse

cor

rect

ion

and

cras

hed

inM

ay 1

965.

Sur

veyo

r 3

(Apr

il 19

67),

see

king

a s

oft l

andi

ng o

na

wes

tern

mar

e, b

ounc

ed t

hree

tim

es b

efor

e fin

ally

tou

chin

gdo

wn

safe

ly. I

ts c

amer

as a

nd s

oil

scoo

p co

nfirm

ed s

uita

ble

terr

ain

and

flatn

ess

for

an A

pollo

land

ing

site

. Mat

chin

g fe

a-tu

res

in S

urve

yor’

s ph

otos

wit

h Ea

rth-

base

d m

aps

and

Luna

rO

rbit

er 3

pho

togr

aphy

ide

ntifi

ed t

he p

reci

se l

andi

ng l

oca-

tion

. Thi

s al

low

ed A

pollo

12

to la

nd (

Nov

embe

r 19

69)

wit

hin

200

m o

f the

Sur

veyo

r, a

sho

rt w

alk

away

(in

spa

cesu

its!

) fo

rA

lan

Bea

n an

d Pe

te C

onra

d. T

his

Apo

llo m

issi

on c

onfir

med

the

abili

ty to

land

at a

pre

cise

loca

tion

on

the

Moo

n, a

cap

a-bi

lity

that

was

cri

tica

l for

late

r A

pollo

pla

nnin

g.

LO4-

126H

1Su

n El

evat

ion:

19.

5°A

ltit

ude:

267

7.28

km

13

7Im

bri

um

Ba

sin R

egio

n

Cop

erni

cus

dom

inat

es

this

dr

amat

ic

scen

e of

M

onte

sC

arpa

tus,

the

sout

hern

rim

of t

he Im

briu

m B

asin

. Rim

a G

ay-

Luss

ac, l

ike

man

y ot

her

lava

rill

es, s

tart

s fr

om a

cra

ter

on th

eou

tsid

e of

the

rin

g bo

undi

ng a

mar

e; h

owev

er,

Rim

a G

ay-

Luss

ac fi

nds

a va

lley

lead

ing

acro

ss t

he r

ing

into

the

bas

inflo

or.

Rim

a G

ay-L

ussa

c ap

pear

s m

ore

like

a co

llaps

ed l

ava

tube

than

a s

urfa

ce c

hann

el. A

lava

tube

is fo

rmed

whe

n la

vaflo

ws

bene

ath

the

cool

ed s

urfa

ce a

nd is

kep

t ope

n by

the

con-

tinu

ous

flow

of h

ot la

va. T

he h

arde

ned

roof

of t

he tu

be in

su-

late

s th

e la

va fr

om c

oolin

g by

rad

iati

on in

to s

pace

. An

inta

ctla

va tu

be is

, of c

ours

e, n

ot v

isib

le fr

om th

e su

rfac

e bu

t if t

hero

of o

f th

e tu

be i

s le

ss t

han

a fe

w m

eter

s in

dep

th, p

rim

ary

and

seco

ndar

y im

pact

s ca

n co

llaps

e it

in ti

me.

LO4-

126H

2Su

n El

evat

ion:

19.

5°A

ltit

ude:

267

7.28

km

13

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Ejec

ta f

rom

Cop

erni

cus,

land

ing

alon

g it

s ra

y ne

ar t

he r

ight

edge

of

this

im

age,

plo

wed

a n

umbe

r of

cra

ters

of

unus

ual

shap

es (

indi

cati

ng a

low

ang

le o

f ap

proa

ch t

o th

e su

rfac

e).

Sout

h of

Lam

bert

, a 6

0-km

bur

ied

crat

er (

Lam

bert

R)

has

left

a fa

int

imag

e of

its

rim

on

the

mar

e su

rfac

e, li

ke t

he f

adin

gsm

ile o

f th

e C

hesh

ire

Cat

of

“Alic

e in

Won

derl

and.

” Su

chpa

tter

ns a

re s

omet

imes

cal

led

ghos

t cr

ater

s. T

his

crat

er h

asar

rive

d af

ter

the

Imbr

ium

Bas

in e

vent

, bu

t be

fore

Mar

eIm

briu

m c

over

ed t

he b

asin

floo

r. T

he c

rate

r ri

m w

as p

roba

-bl

y co

mpl

etel

y co

vere

d w

ith

mar

e la

va,

but

afte

r th

e la

vaco

oled

and

con

trac

ted,

the

rim

rea

ppea

red

as a

mar

e ri

dge.

The

n La

mbe

rt a

rriv

ed, c

over

ing

the

ridg

e ov

er t

he n

orth

ern

rim

of

the

ghos

t cr

ater

wit

h ej

ecta

. Cop

erni

cus

then

dra

ped

rays

ove

r th

e co

mpo

siti

on fo

r fu

rthe

r in

tere

st.

LO4-

126H

3Su

n El

evat

ion:

19.

5°A

ltit

ude:

267

7.28

km

13

9Im

bri

um

Ba

sin R

egio

n

The

30-

km c

rate

r La

mbe

rt h

as m

ulti

ple

circ

umfe

rent

ial r

ings

in i

ts fl

oor,

sug

gest

ing

that

it

has

pene

trat

ed t

he s

olid

mar

esu

rfac

e an

d hi

t so

met

hing

dif

fere

nt b

elow

, sem

imol

ten

lava

or p

erha

ps t

he m

elt

shee

t of

the

bas

in fl

oor

bene

ath

the

mar

e. S

ince

Lam

bert

lef

t it

s ej

ecta

bla

nket

on

the

mar

esu

rfac

e, a

fre

sh fl

ow (

Apo

llo 1

5 fr

ame

M10

09)

has

cove

red

muc

h of

the

east

ern

sect

or o

f Lam

bert

’s s

econ

dary

fiel

d. T

heti

ny c

rate

r Sa

mps

on is

in th

e ce

nter

of a

sha

llow

30-

km d

ome

and

coul

d be

a s

ourc

e of

thi

s flo

w.

The

pyr

amid

al r

ocks

nort

heas

t of

Lam

bert

cou

ld b

e pe

aks

of a

n in

ner

ring

of

the

Imbr

ium

Bas

in. T

he c

ente

r of

the

basi

n (3

3°N

, 18°

W)

is n

ear

the

top

of th

is p

hoto

.

LO4-

127H

1Su

n El

evat

ion:

21.

8°A

ltit

ude:

288

6.35

km

14

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

cen

ter

of M

are

Imbr

ium

, nea

r th

e bo

ttom

of t

his

pict

ure

and

the

top

of L

O4-

127H

1, i

s ne

arly

dev

oid

of m

are

ridg

esan

d ri

lles.

Onl

y im

pact

cra

ters

and

ray

s re

lieve

the

uni

for-

mit

y of

sur

face

topo

grap

hy.

LO4-

127H

2Su

n El

evat

ion:

21.

8°A

ltit

ude:

288

6.35

km

14

1Im

bri

um

Ba

sin R

egio

n

The

Mon

tes

Alp

es c

onst

itut

e th

e no

rthe

rn r

im o

f th

eIm

briu

m B

asin

, whi

ch p

asse

s th

roug

h th

e no

rthe

rn p

art

ofth

e m

agni

ficen

t La

te I

mbr

ian

crat

er P

lato

. Pl

ato

falls

on

a“c

onti

nent

al d

ivid

e” i

n a

sens

e: r

ima

dire

ct fl

ows

from

its

oute

r ra

mpa

rts

sout

h to

war

d th

e ce

nter

of

the

Imbr

ium

Bas

in a

nd n

orth

tow

ard

the

basi

n’s

oute

r tr

ough

, w

hich

unde

rlie

s M

are

Frig

oris

. The

rill

e la

bele

d R

imae

Pla

to in

this

phot

o is

a

trib

utar

y of

a

larg

er

syst

em.

It

seem

s to

flo

w b

enea

th th

e su

rfac

e ne

ar th

e ed

ge o

f the

pho

to, p

ossi

bly

into

a l

ava

tube

tha

t su

rfac

es a

bout

15

km d

owns

lope

(L

O4-

115H

3). P

lato

and

Mar

e Fr

igor

is a

re b

elie

ved

to h

ave

been

floo

ded

in t

he E

rato

sthe

nian

age

, wel

l aft

er t

he p

art

ofM

are

Imbr

ium

see

n so

uth

of P

lato

in th

is p

ictu

re. T

he s

harp

crat

ers

in t

he 1

0-km

ran

ge a

re p

roba

bly

seco

ndar

ies

from

Plat

o.

LO4-

127H

3Su

n El

evat

ion:

21.

8°A

ltit

ude:

288

6.35

km

14

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Timocharis is a crater with moderatelysharp features but whose ray pattern hasblended with the surrounding terrain due to exposure to the solar wind andgardening by meteorite bombardment.These characteristics, plus measurementsof craters on its floor and ejecta, establishits age as Eratosthenian.

Copernicus is just south of MontesCarpatus, the local name of the highestring of the Imbrium Basin. The ejectapattern of this moderately young andspectacular crater is typical of both largecraters and basins. A rampart of materialis thrown outside of the rim. Further out,there is a heavy blanket of ejecta withradial striations. At about one radiusaway from the rim, the ejecta blanketthins, leaving uncovered areas, and thenbecomes a field of secondary craters for adistance of about one diameter awayfrom the rim. Rays of fine, bright mater-ial extend for many diameters.

Well south of Copernicus, there areridges and valleys from the NubiumBasin (overlain with Imbrium secon-daries). A pair of simultaneous im-pactors produced Fauth and its smallerunnamed companion. 1

43

Imb

rium

Ba

sin R

egio

n

The

sur

face

of

Mar

e Im

briu

m, l

ike

that

of

all l

arge

mar

e, i

str

aver

sed

by lo

w r

idge

s be

lieve

d to

res

ult

from

com

pres

sion

stre

sses

as

the

mar

e co

ols

and

cont

ract

s. L

ava

may

find

its

way

to

the

surf

ace

thro

ugh

faul

ts i

n th

ese

ridg

es. T

here

is

alo

w 3

0-km

dom

e to

pped

by

crat

er S

amps

on t

hat

may

be

aso

urce

for

such

a fl

ow.

LO4-

122H

1Su

n El

evat

ion:

20.

7°A

ltit

ude:

289

5.02

km

14

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Bas

ins

ofte

n ha

ve r

ings

ins

ide

thei

r ri

m a

s w

ell

as o

utsi

de.

Mon

tes

Ten

erif

fe, M

ons

Pico

, and

the

pea

k to

the

sou

th o

fM

ons

Pico

may

be

sign

s of

suc

h a

ring

, m

ost

of w

hich

is

cove

red

by d

eep

lava

flow

s.

LO4-

122H

2Su

n El

evat

ion:

20.

7°A

ltit

ude:

289

5.02

km

14

5Im

bri

um

Ba

sin R

egio

n

Montes Apenninus marks the rim of theImbrium Basin and the edge of MareImbrium. As in other maria and otherparts of Mare Imbrium, there are radialand circumferential ridges near thisedge of the mare. Pupin is interestingbecause it is a bright mound with acentral crater and no ray pattern, sug-gesting that it may be a volcanic feature.A pair of matched impactors may havecaused Feuillee and Beer. Wallace hasbeen nearly flooded, an indication ofthe depth of lava there.

Sinus Aestuum was formed by lavaflowing into the valley south of the rimof Imbrium, as Mare Frigoris covers the valley north of the Montes Alpes.Eratosthenes is the type crater of theEratosthenian Period; it formed afterSinus Aestuum was flooded. long afterthe Imbrium impact. However, rays havebeen nearly blended away and its rimstructure has been slightly degraded.

Stadius, flooded by lava that has beencovered by ejecta from Eratosthenes,must be from an earlier time. Darkmantling material surrounds Gambartand the nearby striations from Nubium.Surveyor 2 (September 1966) crashedafter an unsuccessful midcourse cor-rection.

14

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Mon

tes

Spiz

berg

en a

nd th

e ne

arby

isla

nd a

rcs

mar

k an

inne

rri

ng o

f th

e Im

briu

m B

asin

, la

rgel

y su

bmer

ged

unde

r th

em

are

surf

ace;

cir

cum

fere

ntia

l mar

e ri

dges

mar

k it

s lo

cati

onin

oth

er s

ecto

rs. T

he M

onte

s A

rchi

med

es r

ange

s, a

ltho

ugh

over

lain

by

ejec

ta fr

om A

rchi

med

es, s

eem

too

mas

sive

to

beca

used

onl

y by

tha

t cr

ater

and

pro

babl

y w

ere

rais

ed b

y on

eor

mor

e ri

ngs

wit

hin

the

Imbr

ium

Bas

in. T

he t

wo

ring

s m

aybe

ana

logo

us to

the

two

rang

es o

f Mon

tes

Roo

k. T

he p

late

auth

ey r

est u

pon

is c

alle

d th

e A

penn

ine

benc

h. A

n ou

ter

ring

of

the

Insu

laru

m B

asin

to

the

sout

hwes

t m

ay a

lso

have

hel

ped

to r

aise

the

elev

atio

n of

the

Ape

nnin

e be

nch.

LO4-

115H

1Su

n El

evat

ion:

20.

9°A

ltit

ude:

290

5.14

km

14

7Im

bri

um

Ba

sin R

egio

n

Prom

onto

rium

Aga

ssiz

mar

ks t

he e

aste

rn e

nd o

f M

onte

sA

lpes

, at

the

nort

heas

tern

sec

tor

of t

he r

im o

f th

e Im

briu

mB

asin

. Mon

s Pi

ton

mar

ks a

rin

g w

ithi

n th

e ba

sin

(see

LO

4-12

2H2

for

mor

e pe

aks

mar

king

tha

t ri

ng).

The

lar

ge m

are

ridg

e th

at u

nder

lies

Piaz

zi S

myt

h m

ay a

lso

be r

elat

ed to

that

ring

. The

ray

s co

me

from

Ari

still

us to

the

sout

heas

t.

LO4-

115H

2Su

n El

evat

ion:

20.

9°A

ltit

ude:

290

5.14

km

14

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Val

lis

Alp

es c

ould

be

a va

lley

form

ed i

n th

e ri

m o

f th

eIm

briu

m B

asin

dur

ing

impa

ct o

r co

uld

rela

te to

a d

eep

frac

-tu

re o

pene

d by

str

esse

s du

ring

or

shor

tly

afte

r th

e im

pact

. It

may

hav

e be

en fl

oode

d w

ith

lava

fro

m M

are

Imbr

ium

, but

the

lava

may

als

o ha

ve c

ome

from

bel

ow, a

s w

ith

rim

ae in

the

area

, flow

ing

in t

his

case

bot

h to

Mar

e Im

briu

m a

nd t

owar

dM

are

Frig

oris

.

LO4-

115H

3Su

n El

evat

ion:

20.

9°A

ltit

ude:

290

5.14

km

14

9Im

bri

um

Ba

sin R

egio

n

Sinu

s M

edii

and

the

unam

ed c

ircu

lar

area

of m

are

to th

e w

est

of it

may

hav

e be

en fo

rmed

in c

rate

rs. B

ode

has

impa

cted

the

first

out

er r

ing

of I

mbr

ium

; Pal

las

and

Mur

chis

on h

ave

been

degr

aded

by

the

form

atio

n of

tha

t ri

ng a

nd t

hen

part

lyco

vere

d by

Im

briu

m e

ject

a. T

he s

quar

e br

ight

are

a in

the

ridg

e be

twee

n Si

nus

Med

ii an

d it

s co

mpa

nion

to

the

wes

t is

an a

rtif

act

due

to a

tem

pora

ry l

oss

of c

omm

unic

atio

nbe

twee

n Lu

nar

Orb

iter

and

the

Dee

p Sp

ace

Net

wor

k.

LO4-

109H

1Su

n El

evat

ion:

20.

5°A

ltit

ude:

269

3.03

km

15

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Sinu

s A

estu

um a

nd M

are

Vap

orum

hav

e flo

oded

the

val

ley

outs

ide

of t

he r

im o

f th

e Im

briu

m B

asin

, w

hich

is

rep-

rese

nted

her

e by

the

Mon

tes

Ape

nnin

us a

nd M

ons

Wol

ff.

Her

e, la

rge

radi

al v

alle

ys fo

rmed

by

the

Imbr

ium

impa

ct c

anbe

see

n. V

allis

Alp

es (

LO4-

115H

3) c

ould

be

a si

mila

r (b

utde

eper

) va

lley.

Mar

co P

olo

can

just

bar

ely

be p

erce

ived

unde

r it

s th

ick

cove

r of

Ape

nnin

us m

ater

ial,

the

inne

r Fr

aM

auro

For

mat

ion,

whi

ch is

equ

ival

ent

to t

he in

ner

Hev

eliu

sFo

rmat

ion

of O

rien

tale

. Thi

s m

ater

ial h

as b

een

esti

mat

ed t

obe

1 t

o 2

km t

hick

nea

r th

e cr

est

of t

he M

onte

s A

penn

inus

.D

ark

man

tlin

g m

ater

ial

cove

rs b

oth

mar

e an

d hi

ghla

ndsu

rfac

es in

the

vici

nity

of R

imae

Bod

e.

LO4-

109H

2Su

n El

evat

ion:

20.

5°A

ltit

ude:

269

3.03

km

15

1Im

bri

um

Ba

sin R

egio

n

The

Ape

nnin

e be

nch

stre

tche

s be

twee

n A

rchi

med

es a

ndM

onte

s A

penn

inus

(se

e th

e no

te f

or L

O4-

115H

1).

Rim

aB

radl

ey is

pre

sum

ably

a s

uper

ficia

l sig

n of

a c

ircu

mfe

rent

ial

faul

t cau

sed

by te

nsio

nal s

tres

s in

this

are

a. I

t cro

sses

mat

er-

ial s

lum

ped

from

the

rim

of

the

Imbr

ium

Bas

in (

here

cal

led

Mon

s B

radl

ey)

and

mar

e su

rfac

e w

ith

seem

ing

indi

ffer

ence

,an

ind

icat

ion

of a

dee

p fr

actu

re.

Not

e th

at t

he s

ize

of t

hesl

ump

bloc

ks s

eem

to

fit t

he c

orre

spon

ding

edg

es o

f M

ons

Bra

dley

. T

his

phot

o an

d LO

4-11

0H1

are

as c

lose

to

the

east

ern

edge

of

the

Imbr

ium

Bas

in a

s is

cov

ered

in

this

chap

ter

on th

e Im

briu

m B

asin

Reg

ion.

The

eas

tern

edg

e an

dej

ecta

to th

e ea

st a

re c

over

ed in

the

chap

ter

on th

e Se

reni

tati

sB

asin

Reg

ion.

LO4-

109H

3Su

n El

evat

ion:

20.

5°A

ltit

ude:

269

3.03

km

15

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

Apo

llo 1

5 la

ndin

g si

te w

as b

oldl

y ch

osen

to

be n

ear

Rim

a H

adle

y an

d M

ons

Had

ley

beyo

nd t

he e

aste

rn e

dge

ofth

is p

ictu

re.

Aut

olyc

us h

as i

mpa

cted

a p

lain

s un

it i

n th

eIm

briu

m B

asin

tha

t ap

pear

s to

be

rich

in

KR

EEP

min

eral

s(p

otas

sium

, rar

e ea

rth

elem

ents

, and

pho

spho

rus)

. It

is t

hepr

obab

le s

ourc

e of

a b

ould

er c

onta

inin

g K

REE

P th

at w

assa

mpl

ed (

1540

5) b

y th

e A

pollo

15

crew

. T

he a

ge o

f th

esa

mpl

e (a

s it

was

pre

sum

ably

res

truc

ture

d by

the

sho

ck o

fth

e A

utol

ycus

impa

ct)

was

foun

d to

be

1.29

bill

ion

year

s, th

eyo

unge

st a

ge o

f all

date

d lu

nar

rock

sam

ples

. If A

utol

ycus

isno

t th

e so

urce

of

this

sam

ple,

the

n it

may

hav

e co

me

from

Ari

still

us. F

or a

ddit

iona

l dis

cuss

ion

of th

e A

pollo

15

site

, see

the

note

for

LO

4-10

3H1

in t

he c

hapt

er o

n th

e Se

reni

tati

sB

asin

Reg

ion

(Cha

pter

9).

LO4-

110H

1Su

n El

evat

ion:

20.

8°A

ltit

ude:

291

5.82

km

15

3Im

bri

um

Ba

sin R

egio

n

LO4-

110H

2Su

n El

evat

ion:

20.

8°A

ltit

ude:

291

5.82

km

15

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Bey

ond

Mon

tes

Alp

es l

ies

the

Alp

es F

orm

atio

n. A

ltho

ugh

sim

ilar

in

rela

tion

ship

to

the

Imbr

ium

Bas

in,

the

Alp

esFo

rmat

ion

has

a ve

ry d

iffe

rent

app

eara

nce

than

the

Fra

Mau

ro F

orm

atio

n (L

O4-

109H

2).

An

obli

que

impa

ct m

ayha

ve i

nduc

ed a

sym

met

ry o

f th

e ej

ecta

bla

nket

. T

he h

um-

moc

ky a

ppea

ranc

e of

the

Alp

es F

orm

atio

n, w

hich

ext

ends

far

beyo

nd M

are

Imbr

ium

, is

sim

ilar

to th

at o

f the

Mon

tes

Roo

kFo

rmat

ion

of t

he O

rien

tale

Bas

in. C

assi

ni a

nd o

ther

nea

rby

crat

ers

of s

imila

r si

ze s

eem

to h

ave

supp

ress

ed th

e ri

m o

f the

Imbr

ium

Bas

in. T

he e

ject

a bl

anke

t of

Cas

sini

has

a m

olte

nap

pear

ance

, as

if t

he im

pact

or la

nded

in m

are

mat

eria

l tha

tha

d no

t ful

ly s

olid

ified

or

that

was

suf

ficie

ntly

hot

that

it w

asliq

uefie

d by

the

ener

gy o

f im

pact

.

8.1. OverviewBasins, Maria, and HighlandsThe Nectaris region (Figure 8.1) has extensive highlands, in-tensively cratered terrain whose large-scale topography hasbeen established in very ancient times (in the Pre-NectarianPeriod).

From the time of the formation of the Nectaris Basin, thehighlands have been affected by ejecta (including secondaryimpactors) from basins such as Nectaris and Imbrium and alsofrom craters such as Tycho, whose rays can be seen streakingacross the southeast portion of the photo in Figure 8.1.

An especially interesting part of this region is the areawhere the Nectaris Basin intersects with the FecunditatisBasin to the west and the Tranquillitatis Basin to the north.

Figure 8.2 illustrates the size of the Nectaris Basin, muchlarger than Mare Nectaris.

Figure 8.3 shows three of the rings of the Nectaris Basin.These rings have been drawn so that the second ring fromthe center is the square root of 2 greater than the inner ringand the third ring from the center is the square root of 2greater than the second ring. With this constraint, the sizeand center of the set of rings have been adjusted to matchtopographic highs.

Like other major basins, Nectaris has thrown a heavyblanket of ejecta that forms radial ridges and troughs outsideof its major ring, the rim. In the case of Nectaris, this ejectablanket has been degraded by further basin impacts to itsnorth and east. However, the formation is clearly seen to thesouth (Figure 8.4).

Chapter 8

Nectaris Basin Region

Figure 8.1. LO4-096M. This picture is centered on the southeastern partof the central highlands of the near side. The small mare east of the centralhighlands is Mare Nectaris. It occupies the middle of the Nectaris Basin,which is much larger than the mare. East of Mare Nectaris, at the edge of thepicture, is the western portion of Mare Fecunditatis. North of Mare Nectarisand Mare Fecunditatis is Mare Tranquillitatis in the Crisium Basin Region.

15

5N

ecta

ris

Ba

sin R

egio

n

Figure 8.2. Part of LO4-083M. The arc of cliffs outlined by the morningsun is the Rupes Altai (the Altai scarp). It outlines the major ring of theNectaris Basin.

Apollo LandingApollo Mission 16 landed in the midst of the south-centralhighlands (LO4-089H3), near the boundary between theCayley and Descartes Formations. This was the first missionwith a Lunar Roving Vehicle, which permitted the astronautsto reach both formations. Before the mission, these terraintypes were thought to be volcanic. In the course of the mis-sion it became clear to both the astronauts, who were partic-ularly well trained in geology, and the support geologists atMission Control that ejecta from Imbrium had covered bothareas. The astronauts revised their sample collection strategyto improve characterization of the impact-dominatedterrain. Analysis of the samples helped establish the age ofthe Imbrium impact event (3.85 billion years). In addition,some samples from the Descartes Formation, probably exca-

vated from an underlying layer of ejecta from the NectarisBasin, were dated at 3.92 billion years.

8.2. High-Resolution ImagesTable 8.1 shows the high-resolution images of the NectarisBasin Region in schematic form.

The following pages show the high-resolution subframesfrom south to north and west to east. That is, they are in theorder LO4-100H1, LO4-100H2, LO4-100H3, LO4-101H1,LO4-101H2, LO4-101H3, LO4-095H1… LO4-053H3.

Photos LO-095H1, LO-083H1, and LO4-071H1 are redun-dant and have not been printed, although the cleaned imagesare in the enclosed CD.

LO096H and LO077H are printed as full frame.

15

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Figure 8.3. LO4-084M. The ridge marked by the innermost ring, whoseeastern sector passes over the Montes Pyrenaeus (LO4-065H2), bounds thecentral area of mare flooding (partly blocked or covered by ejecta from latercraters). The outer ring is the main ring; aligned with Rupes Altai. Troughsbetween the rings are partly filled with mare.

Figure 8.4. LO4-052M. These deep troughs and ridges south of theNectaris Basin were produced by ejecta from that basin. The pattern issimilar to the Fra Mauro Formation of the Imbrium Basin, to the HeveliusFormation of the Orientale Basin, and to the secondary-impact crater fieldsof those basins.

0–27 N 109 102 097 090 085 078 073 66 061 054

0–27 S 108 101 096 089 084 077 072 65 060 053 046

27 S–56 S 107 100 095 088 083 076 071 64 059 052

56 S–90 S 094 082 070 058 044

Longitude 3 W 4 E 10 E 10 E 16 E 24 E 30 E 38 E 49 E 57 E 63 Eat Equator

Table 8.1. The cells shown in white represent the high-resolution photos of the Nectaris Basin Region (LO4-XXX H1, -H2, and -H3, where XXX is the PhotoNumber). The Humorum Basin Region is to the west, the Imbrium Basin Region is to the northwest, the Serenitatis Basin Region is to the north, the EasternBasins Region is to the east, and the South Polar Region is to the south.

In t

his

high

land

s re

gion

, th

e re

lati

ve a

ges

of c

rate

rs a

reju

dged

by

the

amou

nt o

f de

grad

atio

n of

the

ir r

ims

and

the

dens

ity

of s

mal

l cr

ater

s on

the

ir fl

oors

. A

ltho

ugh

the

larg

ecr

ater

s he

re a

ssig

ned

to t

he P

re-N

ecta

rian

Per

iod,

Bac

ose

ems

muc

h fr

eshe

r th

an H

omm

el,

but

Tan

neru

s m

ay b

eyo

unge

r th

an B

aco.

Fre

sh-l

ooki

ng c

rate

rs in

the

5-k

m r

ange

in t

his

area

are

bel

ieve

d to

be

Ori

enta

le B

asin

sec

onda

ries

,ev

en t

houg

h th

e ce

nter

of

that

bas

in i

s fu

lly 9

0°ar

ound

the

Moo

n (a

bout

150

0 km

to

the

wes

t) a

way

. Lig

ht r

ays

in t

heea

st-w

est

dire

ctio

n an

d th

e st

ring

s of

cra

ters

sou

th o

fT

anne

rus

are

from

Tyc

ho.

LO4-

100H

1Su

n El

evat

ion:

21.

3°A

ltit

ude:

297

8.20

km

15

7N

ecta

ris

Ba

sin R

egio

n

The

clu

ster

of

crat

ers

near

the

int

erse

ctio

n of

Sto

fler

and

Fara

day

is a

ligne

d in

the

dir

ecti

on o

f th

e Im

briu

m B

asin

,w

hose

rim

is

abou

t 20

00 k

m a

way

. T

he c

lust

ers

alon

g th

e 10

°ea

st m

erid

ian

are

alig

ned

wit

h th

e di

rect

ion

of th

e So

uth

Pole

–Aik

en B

asin

, abo

ut 1

300

km a

way

, but

may

com

e fr

omth

e yo

unge

r Se

reni

tati

s B

asin

, abo

ut 1

800

km t

o th

e no

rth-

nort

heas

t.

LO4-

100H

2Su

n El

evat

ion:

21.

3°A

ltit

ude:

297

8.20

km

15

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

nei

ghbo

ring

cra

ters

Wer

ner

and

Alia

cens

is r

evea

l muc

hof

the

mec

hani

cs o

f cra

ter

form

atio

n an

d su

bseq

uent

ero

sion

in t

his

high

land

are

a. T

he e

ject

a fr

om W

erne

r ha

s be

en d

e-po

site

d on

the

rim

of A

liace

nsis

; the

forc

e of

the

dep

osit

ion,

perh

aps

aide

d by

the

sho

ck w

ave

of t

he im

pact

, has

pus

hed

abou

t 20

km

of

the

rim

of

Alia

cens

is o

nto

its

floor

. Bec

ause

thes

e tw

o cr

ater

s ar

e si

mila

r in

siz

e an

d ha

ve im

pact

ed s

im-

ilar

terr

ain,

they

pro

babl

y ha

d si

mila

r to

pogr

aphy

whe

n th

eyw

ere

form

ed. T

he o

lder

Alia

cens

is h

as h

ad t

he t

extu

re o

f it

sej

ecta

bla

nket

ero

ded

away

by

subs

eque

nt i

mpa

cts.

Man

ym

ore

smal

l cra

ters

(le

ss th

an 5

km

) ca

n be

see

n in

the

area

of

its

form

er e

ject

a bl

anke

t tha

n in

that

of W

erne

r.

LO4-

100H

3Su

n El

evat

ion:

21.

3°A

ltit

ude:

297

8.20

km

15

9N

ecta

ris

Ba

sin R

egio

n

Rad

ial e

ject

a fe

atur

es fr

om E

rato

sthe

nian

cra

ter

Wer

ner

can

be s

een

up t

o tw

o ra

dii

from

its

rim

. Thi

s ej

ecta

bla

nket

is

supe

rim

pose

d on

irr

egul

ar c

rate

rs,

ridg

es,

and

valle

ys t

hat

are

radi

al t

o th

e Im

briu

m B

asin

, pa

rt o

f th

e Fr

a M

auro

Form

atio

n. S

econ

dary

cra

ters

fro

m t

he I

mbr

ium

Bas

in a

lso

perv

ade

this

are

a, e

xcep

t w

here

the

y ar

e co

vere

d by

the

Wer

ner

ejec

ta b

lank

et.

Ben

eath

the

Fra

Mau

ro F

orm

atio

n,Pl

ayfa

ir,

Api

anus

, an

d K

ruse

nste

rn h

ave

redi

stri

bute

d th

eri

m m

ater

ial

from

an

olde

r un

nam

ed 1

15-k

m c

rate

r. T

hecr

ater

clu

ster

nea

r th

e ri

ght

edge

of

this

pho

to i

s fr

om t

heN

ecta

ris

Bas

in.

LO4-

101H

1Su

n El

evat

ion:

21.

1°A

ltit

ude:

272

0.44

km

16

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Dee

p gr

oove

s fo

rmed

by

chai

ns o

f cra

ters

illu

stra

te th

is a

rea

of t

he F

ra M

auro

For

mat

ion.

Tra

ces

of s

uch

groo

ves

rem

ain

on t

he fl

oor

of A

lbat

egni

us, b

ut a

ppea

r to

hav

e be

en b

urie

dby

a r

elat

ivel

y sm

ooth

laye

r of

pla

ins

mat

eria

l. In

som

e ar

eas

such

mat

eria

l may

hav

e be

en d

epos

ited

by

basi

n ej

ecta

, but

the

abru

pt t

rans

itio

n he

re b

etw

een

groo

ves

and

plai

ns s

ug-

gest

s a

volc

anic

ori

gin

from

wit

hin

the

crat

er.

Vog

el a

nd

its

com

pani

on t

o th

e no

rth

seem

to

be s

econ

dari

es f

rom

Imbr

ium

ass

ocia

ted

wit

h a

larg

e gr

oove

. Air

y, o

n th

e ot

her

hand

, has

bee

n ne

arly

bur

ied

by Im

briu

m e

ject

a.

LO4-

101H

2Su

n El

evat

ion:

21.

1°A

ltit

ude:

272

0.44

km

16

1N

ecta

ris

Ba

sin R

egio

n

Thi

s ar

ea is

dom

inat

ed b

y th

e Fr

a M

auro

For

mat

ion,

em

erg-

ing

from

the

mar

e su

rfac

e of

Sin

us M

edii

and

the

floor

of

the

Hip

parc

hus

crat

er. T

he fl

oor

of P

tole

mae

us, l

ike

that

of

Alb

eteg

nius

(LO

4-10

1H2)

, is

cove

red

wit

h lig

ht p

lain

s m

ater

-ia

l tha

t has

obs

cure

d th

e Fr

a M

auro

For

mat

ion.

LO4-

101H

3Su

n El

evat

ion:

21.

1°A

ltit

ude:

272

0.44

km

16

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

095H

2Su

n El

evat

ion:

21.

6°A

ltit

ude:

297

5.51

km

16

3N

ecta

ris

Ba

sin R

egio

n

The

nor

thw

est

floor

s of

Mau

roly

cus

and

Bar

ociu

s ar

eco

vere

d w

ith

heav

y de

posi

ts o

f ej

ecta

tho

ught

to

be t

hem

argi

n of

the

oute

r de

posi

ts fr

om th

e Im

briu

m B

asin

. Som

ech

ains

of

smal

l se

cond

arie

s fr

om t

he n

orth

-nor

thea

st a

refr

om N

ecta

ris,

who

se r

im i

s ab

out

1.5

radi

i aw

ay.

Fres

her

clus

ters

of

crat

ers

are

prob

ably

fro

m t

he I

mbr

ium

Bas

in,

even

tho

ugh

this

are

a is

tw

o ba

sin

radi

i aw

ay f

rom

the

Imbr

ium

rim

.

Thi

s in

tere

stin

g pi

ctur

e sh

ows

cros

sing

pat

tern

s of

cra

ter

chai

ns a

nd s

tria

tion

s fr

om I

mbr

ium

to

the

nort

h-no

rthw

est

and

Nec

tari

s to

the

eas

t-no

rthe

ast.

The

floo

rs o

f G

emm

aFr

isiu

s, G

ooda

cre,

and

the

cra

ters

to

the

sout

heas

t sh

owre

surf

acin

g by

ligh

t pla

ins

mat

eria

ls.

LO4-

095H

3Su

n El

evat

ion:

21.

6°A

ltit

ude:

297

5.51

km

16

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-096H1Sun Elevation: 21.8°Altitude: 2722.26 km

The fresh, sharp craters in the clustersoutheast of Hipparchus are all bright inClementine albedo data. The rays andbright ejecta come mostly from thecrater to the northeast of Hind. Themottled dark areas are concentrated inlow-lying terrain, with the exception ofa dark plateau south of Lade with sharpedges that may be a flow. Clementinegravity data show a positive anomalyhere that is similar to those under mareareas, but weaker. Could there havebeen an early stage of mare formationhere that did not go to completion?

Burnham, in the midst of light plains,has a roughly circular raised rim, butthe floor is not depressed. Further, the rim is breached with grooves thatsuggest flow to the outside. BetweenBurnham and Abulfeda there is anotherirregular rim, surrounded by a flow witha lobate edge. These features may havebeen produced by molten ejecta fromthe Nectaris Basin.

The ridge and the crater chain nearPlayfair are from the direction of theNectaris Basin to the east-northeast, as are many other striations in thisarea. Many of the craters show signs ofbeing covered by Nectaris ejecta and soare considered Pre-Nectarian. However,Playfair is relatively unmarked, so it hasbeen classified as Nectarian.

16

5N

ecta

ris

Ba

sin R

egio

n

Not

e ho

w fl

at t

his

area

see

ms,

rel

ativ

e to

sur

roun

ding

are

as.

It w

ould

be

the

nort

heas

t qu

adra

nt o

f the

floo

r of

a p

ossi

ble

larg

e Pr

e-N

ecta

rian

bas

in n

amed

Mut

us-V

laq.

The

bas

inflo

or w

ould

hav

e ob

liter

ated

any

ear

lier

crat

erin

g an

d pr

o-vi

ded

the

basi

c fla

tnes

s. T

hen,

sec

onda

ries

and

oth

er e

ject

afr

om th

e N

ecta

ris

Bas

in w

ould

hav

e ar

rive

d, fo

llow

ed b

y se

c-on

dari

es fr

om Im

briu

m.

LO4-

088H

2Su

n El

evat

ion:

21.

7°A

ltit

ude:

297

3.74

km

16

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Pons

, W

ilki

ns,

Zag

ut,

Lind

emau

, an

d R

abbi

Lev

i li

e on

am

assi

ve h

ighl

ands

rid

ge th

at h

as th

e hi

ghes

t ele

vati

on o

n th

een

tire

nea

r si

de, a

bout

400

0 m

abo

ve t

he fl

oor

of t

he n

earb

yN

ecta

ris

Bas

in. T

he h

ighl

y er

oded

cra

ters

Zag

ut a

nd R

abbi

Levi

are

Pre

-Nec

tari

an in

age

and

hav

e be

en c

over

ed in

eje

cta

from

the

Nec

tari

s B

asin

. Gro

oves

and

rid

ges

from

Nec

tari

sca

n be

see

n in

the

nort

heas

t rim

of Z

agut

and

on

the

floor

of

Rab

bi L

evi.

Cha

ins

of s

econ

dari

es fr

om Im

briu

m li

e be

twee

nPo

ntan

us a

nd W

ilkin

s.

LO4-

088H

3Su

n El

evat

ion:

21.

7°A

ltit

ude:

297

3.74

km

16

7N

ecta

ris

Ba

sin R

egio

n

Cle

men

tine

ele

vati

on d

ata

show

a d

epre

ssio

n th

at m

ay m

ark

a ve

ry o

ld c

rate

r ab

out

225

km i

n di

amet

er,

cent

ered

nea

r 17

°ea

st, 2

6°so

uth

(das

hed

circ

le).

The

floo

r of

thi

s po

ssib

lecr

ater

wou

ld b

e ab

out 1

500

m b

elow

the

rim

. The

are

a to

the

east

is h

eavi

ly c

over

ed w

ith

the

Nec

tari

s ej

ecta

bla

nket

.

LO4-

089H

1Su

n El

evat

ion:

21.

9°A

ltit

ude:

272

4.41

km

16

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s un

usua

l te

rrai

n ha

s be

en c

alle

d th

e D

esca

rtes

For

-m

atio

n; t

he a

rea

is h

eavi

ly c

over

ed b

y ej

ecta

fro

m t

heN

ecta

ris

Bas

in, w

hose

mai

n ri

ng is

onl

y on

e ba

sin

radi

us t

oth

e ea

st. D

esca

rtes

its

elf

has

been

nea

rly

buri

ed b

y N

ecta

ris

ejec

ta. A

bulfe

da, h

owev

er, s

how

s no

sig

n of

eje

cta,

and

mus

tbe

of

the

Nec

tari

an P

erio

d or

you

nger

. C

aten

a A

bulf

eda

isno

t qui

te r

adia

l to

the

cent

er o

f the

Imbr

ium

Bas

in, a

ltho

ugh

it a

ligns

wit

h th

e so

uthw

este

rn r

im o

f tha

t bas

in. T

he c

aten

a’s

impa

ctor

s co

uld

be a

set

of p

rim

arie

s fr

om a

dis

rupt

ed c

omet

like

Shoe

mak

er-L

evy

9.

LO4-

089H

2Su

n El

evat

ion:

21.

9°A

ltit

ude:

272

4.41

km

16

9N

ecta

ris

Ba

sin R

egio

n

Apo

llo 1

6 la

nded

in t

his

site

to

expl

ore

both

the

ligh

t pl

ains

(Cay

ley

Form

atio

n) a

nd t

he n

earb

y hu

mm

ocky

Des

cart

esFo

rmat

ion.

A m

ajor

obj

ecti

ve w

as t

o co

nfirm

tha

t th

e tw

ofo

rmat

ions

wer

e vo

lcan

ic.

Inst

ead,

ana

lysi

s of

the

roc

ksa

mpl

es s

how

ed t

hat

the

form

atio

ns w

ere

ejec

ta d

epos

its.

Bot

h D

esca

rtes

and

Cay

ley

Form

atio

ns a

re p

roba

bly

loca

las

pect

s of

eje

cta

from

the

Im

briu

m B

asin

. M

ost

of t

hesa

mpl

es w

ere

of c

ours

e of

the

uppe

r la

yer,

from

the

youn

ger

Imbr

ium

Bas

in, b

ut s

ome

sam

ples

may

be

from

Nec

tari

s. I

fso

, the

age

s of

thes

e sa

mpl

es e

stab

lish

the

age

of th

e N

ecta

ris

Basi

n (a

nd th

us th

e bo

unda

ry b

etw

een

the

Pre-

Nec

tari

an a

ndN

ecta

rian

Per

iods

) as

3.9

2 ae

ons

(bill

ions

of y

ears

bef

ore

the

pres

ent)

.

LO4-

089H

3Su

n El

evat

ion:

21.

9°A

ltit

ude:

272

4.41

km

17

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

reg

ion

cove

red

by h

eavy

, hu

mm

ocky

dep

osit

s in

the

vici

nity

of J

anss

en is

the

type

are

a of

the

Jans

sen

Form

atio

n,an

eje

cta

blan

ket

from

the

Nec

tari

s B

asin

. It

is c

ompa

rabl

eto

the

Inn

er H

evel

ius

Form

atio

n of

the

Ori

enta

le B

asin

and

the

Fra

Mau

ro F

orm

atio

n of

the

Imbr

ium

Bas

in. T

his

form

a-ti

on h

as b

een

obsc

ured

by

Imbr

ium

eje

cta

to t

he w

est

of t

heba

sin

(not

e th

e ch

ain

of s

econ

dari

es in

the

uppe

r le

ft c

orne

r).

The

floo

r an

d ej

ecta

of

Jans

sen

(LO

4-07

6H2)

are

cov

ered

wit

h N

ecta

ris

ejec

ta.

LO4-

083H

2Su

n El

evat

ion:

22.

8°A

ltit

ude:

297

1.86

km

17

1N

ecta

ris

Ba

sin R

egio

n

Rup

es A

ltai

(LO

4-08

4H1)

mar

ks t

he m

ain

ring

of

the

Nec

tari

s B

asin

. Thi

s ar

ea il

lust

rate

s th

e m

etho

ds o

f ass

igni

ngag

es t

o la

rge

crat

ers.

Zag

ut,

Rab

bi L

evi,

and

Ric

cius

hav

ebe

en c

ompl

etel

y or

par

tly

cove

red

by e

ject

a fr

om N

ecta

ris

and

are

ther

efor

e as

sign

ed t

o th

e Pr

e-N

ecta

rian

Per

iod.

Lind

enau

and

Sti

bori

us a

re p

unch

ed i

nto

the

Nec

tari

anej

ecta

and

in

addi

tion

are

fre

e of

Im

briu

m s

econ

dari

es t

hat

are

com

mon

her

e. T

he s

harp

ness

of t

heir

rim

s, c

entr

al p

eaks

,an

d ej

ecta

are

sim

ilar

to t

hose

of

Schl

uter

, w

hich

ove

rlie

sO

rien

tale

(LO

4-18

1H3)

; the

refo

re, t

hey

have

bee

n as

sign

ed to

the

Late

Im

bria

n Ep

och.

Rot

hman

n, s

harp

er y

et a

nd r

ela-

tive

ly u

ncra

tere

d, is

con

side

red

Erat

osth

enia

n.

LO4-

083H

3Su

n El

evat

ion:

22.

8°A

ltit

ude:

297

1.86

km

17

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Rup

es A

ltai

(A

ltai

Sca

rp)

cont

inue

s no

rth

of t

his

(LO

4-08

4H2)

. It

fol

low

s th

e m

ain

ring

of

the

Nec

tari

s B

asin

and

is

sim

ilar

in

natu

re t

o M

onte

s A

penn

ine

and

Mon

tes

Cor

dille

ra. B

ecau

se it

is s

o sh

arp,

it h

as b

een

sugg

este

d th

at it

was

for

med

or

fres

hene

d by

a l

ater

tec

toni

c fa

ult

that

fol

-lo

wed

the

ring

. On

the

othe

r ha

nd, t

he s

harp

ness

may

sim

ply

have

bee

n m

aint

aine

d by

slu

mpi

ng o

f the

wal

l.

LO4-

084H

1Su

n El

evat

ion:

23.

1°A

ltit

ude:

272

6.79

km

17

3N

ecta

ris

Ba

sin R

egio

n

The

nor

ther

n en

d of

Rup

es A

ltai

is

in t

he l

ower

lef

t-ha

ndco

rner

of t

his

phot

o. F

irst

Cyr

illus

and

then

The

ophi

lus

have

land

ed i

n th

e ar

ea b

etw

een

the

mai

n ri

ng a

nd o

ne o

f th

ein

ner

ring

s of

the

Nec

tari

s B

asin

. Cyr

illus

is c

onsi

dere

d to

be

of t

he N

ecta

rian

Per

iod

and

The

ophi

lus,

whi

ch a

ppea

rs t

oha

ve p

ushe

d ri

m m

ater

ial o

f Cyr

illus

ont

o it

s flo

or, i

s fr

ee o

fIm

briu

m s

tria

tion

s, a

nd h

as a

low

inc

iden

ce o

f cr

ater

s on

it

s flo

or,

has

been

ass

igne

d to

the

Era

tost

heni

an P

erio

d.T

heop

hilu

s is

bel

ieve

d to

hav

e th

row

n so

me

frag

men

ts o

fM

are

Nec

tari

s to

the

high

land

ing

site

of A

pollo

16

(LO

4-89

H3)

. Sa

mpl

es f

rom

suc

h ro

cks

wer

e ag

ed a

t 3.

74 a

eons

(bil

lion

s of

yea

rs a

go).

The

Nec

tari

an i

mpa

ct w

ould

be

earl

ier,

est

imat

ed a

t 3.9

2 ae

ons.

LO4-

084H

2Su

n El

evat

ion:

23.

1°A

ltit

ude:

272

6.79

km

17

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Mar

e T

ranq

uilli

tati

s an

d th

e A

pollo

11

land

ing

site

are

dis

-cu

ssed

in

the

chap

ter

on t

he S

eren

itat

is B

asin

Reg

ion

(Cha

pter

9).

The

Kan

t Pl

atea

u, f

rom

Mon

s Pe

nck

to e

ast

ofZ

olne

r (L

O4-

089H

3),

rise

s 2

km a

bove

the

sur

roun

ding

plai

ns.

Upl

ift

from

a t

ripl

e in

ters

ecti

on o

f ri

ngs

from

the

Nec

tari

s, I

mbr

ium

, an

d T

ranq

uilli

tati

s ba

sins

may

hav

era

ised

it.

Sin

us A

sper

itat

is h

as a

sm

all

grav

ity

anom

aly

(mas

con)

tha

t in

dica

tes

that

thi

s ba

y ha

s it

s ow

n so

urce

of

lava

. M

uch

of S

inus

Asp

erit

atis

has

bee

n co

vere

d w

ith

The

ophi

lus

ejec

ta,

the

ligh

ter

mat

eria

l in

the

low

er r

ight

corn

er o

f the

pho

to. B

eyon

d th

e T

heop

hilu

s ej

ecta

is a

hea

vyej

ecta

bla

nket

fro

m t

he I

mbr

ium

Bas

in, w

hose

rim

is

abou

t1.

5 ba

sin

radi

i aw

ay.

LO4-

084H

3Su

n El

evat

ion:

23.

1°A

ltit

ude:

272

6.79

km

17

5N

ecta

ris

Ba

sin R

egio

n

Wat

t is

clea

rly

of th

e Pr

e-N

ecta

rian

Per

iod

beca

use

the

stri

a-ti

ons

of N

ecta

rian

eje

cta

trav

erse

its

wal

l and

floo

r. S

tein

heil

and

Bie

la h

ave

sim

ilar

leve

ls o

f de

grad

atio

n an

d ar

e th

ere-

fore

like

ly to

be

of th

e sa

me

peri

od. B

ecau

se S

tein

heil

is in

an

area

of h

eavy

Nec

tari

an e

ject

a bu

t is

free

of i

t, th

ey m

ust b

oth

be N

ecta

rian

or

youn

ger.

The

cra

ters

tha

t ha

ve i

mpa

cted

Bie

la a

re Im

briu

m s

econ

dari

es, s

o bo

th c

rate

rs m

ust b

e ol

der

than

the

Ear

ly I

mbr

ian

Epoc

h. T

here

fore

, bo

th B

iela

and

Stei

nhei

l ar

e cl

assi

fied

as o

f th

e N

ecta

rian

Per

iod.

Lig

htpl

ains

are

nor

th a

nd e

ast o

f Bie

la.

LO4-

076H

1Su

n El

evat

ion:

22.

1°A

ltit

ude:

297

1.56

km

17

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Fabr

iciu

s an

d Ja

nsse

n ar

e a

stud

y in

con

tras

ting

age

. Jan

ssen

,of

the

Pre

-Nec

tari

an P

erio

d, h

as i

ts r

im o

bscu

red

by e

ject

afr

om th

e N

ecta

ris

Bas

in a

nd b

oth

rim

and

floo

r ar

e im

pact

edby

Imbr

ium

sec

onda

ries

. Fab

rici

us, o

n th

e ot

her

hand

, sho

ws

shar

p te

xtur

e in

its

eje

cta,

cen

tral

pea

k, a

nd t

erra

ced

wal

l.T

he F

abri

cius

im

pact

cou

ld b

e as

lat

e as

the

Era

tost

heni

anPe

riod

. Rim

ae J

anss

en c

ould

be

the

surf

ace

man

ifes

tati

on o

ffa

ults

cau

sed

by s

tres

s fr

om t

he h

eavy

Nec

tari

an e

ject

a or

coul

d be

fau

lts

indu

ced

by t

he im

pact

of

Fabr

iciu

s. A

n ev

enol

der,

mor

e de

grad

ed,

unna

med

cra

ter

unde

rlie

s Ja

nsse

n,w

ith

its

cent

er n

ear

the

nort

heas

tern

rim

of J

anss

en.

LO4-

076H

2Su

n El

evat

ion:

22.

1°A

ltit

ude:

297

1.56

km

17

7N

ecta

ris

Ba

sin R

egio

n

Picc

olom

ini

has

oblit

erat

ed t

he s

outh

east

ern

end

of R

upes

Alt

ai T

he P

icco

lom

ini e

ject

a bl

anke

t ha

s sp

read

into

cra

ters

thou

ght

to b

e se

cond

arie

s of

Im

briu

m (

to t

he n

orth

wes

t).

Picc

olom

ini

is d

ated

in

the

Late

Im

bria

n Ep

och,

as

isSt

ibor

ius.

Rot

hman

n, w

hich

has

sha

rper

det

ail,

is d

ated

in

the

Erat

osth

enia

n Pe

riod

.

LO4-

076H

3Su

n El

evat

ion:

22.

1°A

ltit

ude:

297

1.56

km

17

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Torricelli may have been formed by apair of impactors. The rim of a flooded88-km crater surrounding Torricelli canbe seen just above the mare surface.There is a positive gravity anomaly atSinus Asperitatis, suggesting that it hadits own source of lava. The last (surface)flow of southern Mare Tranquillitatisdid not enter the sinus; its edge can beseen at the northeast sector of SinusAsperitatis.

The northwestern part of MareNectaris has been covered with ejectafrom Theophilus, covered in turn withrays from Madler. A couple of small(about 2 km) craters have penetratedthe Theophilus ejecta to produce theirown dark halos of mare material. Itappears that a landslide from a hill tothe north has cascaded over the rim ofMadler onto its floor, as well as over theejecta blanket of Madler, exposing verylight material.

The next ring inside of Rupes Altaican be seen arcing across this image,passing halfway between Piccolominiand Fracastorius. The next inner ring is tangent to the southern rim of Fra-castorius. Imbrium secondaries, craterchains, and other ejecta cover this partof the floor of the Nectaris Basin.

17

9N

ecta

ris

Ba

sin R

egio

n

Val

lis R

heit

a an

d cr

ater

cha

ins

to it

s w

est a

re r

adia

ting

from

the

Nec

tari

s B

asin

. Thi

s ar

ea is

the

best

pre

serv

ed p

art o

f the

Jans

sen

Form

atio

n, t

he e

ject

a bl

anke

t fr

om t

he N

ecta

ris

Bas

in.

The

vis

ibil

ity

of J

anss

en i

tsel

f, a

ltho

ugh

clea

rly

cove

red

by t

he d

epos

it f

rom

Nec

tari

s, i

ndic

ates

tha

t th

ebl

anke

t is

less

than

1 k

m th

ick.

The

Ste

inhe

il im

pact

or

som

eot

her

acti

vity

see

ms

to h

ave

thro

wn

an u

nusu

al l

ayer

edej

ecta

ont

o th

e so

uthe

ast fl

oor

of Ja

nsse

n.

LO4-

071H

2Su

n El

evat

ion:

23.

5°A

ltit

ude:

29.

72.2

9 km

18

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Nea

nder

has

im

pact

ed t

he s

outh

ern

sect

or o

f th

e m

ain

ring

of t

he N

ecta

ris

Bas

in. I

t ap

pear

s th

at l

ava

has

flow

ed f

rom

the

outs

ide

of th

e m

ain

ring

sou

th to

the

crat

er B

renn

er. T

hefla

t-flo

ored

val

ley

has

subs

eque

ntly

bee

n co

vere

d w

ith

ejec

ta,

prob

ably

from

Pic

colo

min

i or

Imbr

ium

. Sim

ilar

flow

s fr

om a

mai

n ri

ng o

utw

ard

(but

wit

h na

rrow

er v

alle

ys)

can

be s

een

atR

ima

Plat

o an

d R

ima

Arc

hyta

s in

the

Imbr

ium

Bas

in R

egio

n(L

O-1

22H

3).

LO4-

071H

3Su

n El

evat

ion:

23.

5°A

ltit

ude:

29.

72.2

9 km

18

1N

ecta

ris

Ba

sin R

egio

n

Thi

s so

uthe

rn s

ecto

r of

the

Nec

tari

s B

asin

cov

ers

thre

e ri

ngs.

The

inn

er r

ing

graz

es t

he s

outh

ern

rim

of

Frac

asto

rius

, the

g (s

omew

hat

inte

rmit

tent

) pa

sses

to

the

nort

h of

Wei

nek,

and

the

mai

n ri

ng p

asse

s th

roug

h N

eand

er. E

ject

afr

om F

raca

stor

ius

and

Imbr

ium

obs

cure

whe

ther

the

floor

of

the

basi

n ha

s be

en fl

oode

d w

ith

mar

e an

d th

en c

over

ed, b

utth

e fla

tnes

s su

gges

ts t

hat

it h

as b

een

flood

ed. T

he s

moo

th-

ness

and

flat

ness

of

the

plai

ns a

rea

to t

he n

orth

east

sug

gest

that

unc

onso

lida

ted

mat

eria

l ha

s be

en s

tron

gly

shak

endo

wn.

Thi

s is

onl

y on

e si

gn t

hat

part

s of

the

floo

r of

the

Nec

tari

s B

asin

hav

e su

bsid

ed i

n on

e or

mor

e su

dden

epis

odes

.

LO4-

072H

1Su

n El

evat

ion:

24.

3°A

ltit

ude:

274

2.43

km

18

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s ce

ntra

l par

t of t

he N

ecta

ris

Bas

in is

ver

y de

eply

cov

ered

wit

h m

are

lava

. Dag

uerr

e, B

ohne

nber

ger,

the

crat

er s

outh

of

Boh

nenb

erge

r, a

nd p

ossi

bly

a cr

ater

wes

t of

Boh

nenb

erge

r(a

ll ne

ar th

e m

argi

ns o

f the

bas

in a

nd a

ll in

the

35-

to 5

0-km

rang

e) h

ave

been

floo

ded.

Thi

s in

dica

tes

that

the

dept

h at

the

mar

gins

is o

f the

ord

er o

f 2 k

m; t

he d

epth

at t

he c

ente

r of

the

basi

n, w

here

the

re i

s no

sig

n of

cra

ters

, is

likel

y to

be

even

mor

e. M

onte

s Py

rena

eus

is t

he e

aste

rn s

ecto

r of

the

inn

er-

mos

t rin

g of

Fig

ure

8.3.

The

cur

ved

ridg

e ab

out 3

5 km

to th

ew

est

of M

onte

s Py

rena

eus

is l

ikel

y to

be

sim

ply

com

pose

d of

ves

tigi

al s

ecto

rs o

f su

bmer

ged

crat

er r

ims.

The

floo

r of

Gau

dibe

rt is

an

extr

eme

exam

ple

of u

plif

t in

crat

ers

near

the

mar

gins

of m

aria

.

LO4-

072H

2Su

n El

evat

ion:

24.

3°A

ltit

ude:

274

2.43

km

18

3N

ecta

ris

Ba

sin R

egio

n

Imbr

ium

eje

cta

has

cove

red

all b

ut t

he la

rger

feat

ures

of t

heN

ecta

ris

Bas

in, s

uch

as V

allis

Cap

ella

, Rim

ae G

uten

berg

, and

the

mai

n ri

ng. T

he p

late

au n

orth

of L

eake

y ha

s be

en r

aise

d at

the

inte

rsec

tion

of

ring

s of

thr

ee b

asin

s (L

O4-

065H

3). V

allis

Cap

ella

was

pro

babl

y fo

rmed

by

ejec

ta fr

om N

ecta

ris.

Rim

aeG

uten

berg

app

ear

to m

ark

radi

al fr

actu

res,

oft

en fo

und

near

mar

e ed

ges

(bot

h M

are

Nec

tari

s an

d M

are

Fecu

ndit

atis

are

near

by).

Cen

sori

nus

is a

sm

all

4.5-

km C

oper

nica

n cr

ater

who

se m

uch

larg

er r

ay s

yste

m i

s ab

out

30 k

m a

cros

s. T

his

crat

er a

nd i

ts r

ay p

atte

rn h

ave

been

pho

togr

aphe

d at

ver

yhi

gh r

esol

utio

n (L

O5-

063H

1, -

H2,

and

-H

3; 2

-m r

esol

utio

n)an

d di

spla

y de

taile

d m

echa

nism

s of

eje

cta

and

ray

form

a-ti

on.

Gut

enbe

rg h

as p

rodu

ced

a la

rge

ejec

ta b

lank

et a

ndpo

ssib

ly s

moo

thed

out

pre

exis

ting

Im

briu

m e

ject

a by

its

impa

ct.

LO4-

072H

3Su

n El

evat

ion:

24.

3°A

ltit

ude:

274

2.43

km

18

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

hea

vy N

ecta

ris

ejec

ta b

lank

et f

orm

ed V

allis

Rhe

ita

and

cove

rs R

eim

anus

tho

roug

hly.

The

eje

cta

thin

s ou

t to

the

sout

h an

d so

uthw

est,

beco

min

g pa

tchy

tow

ard

Pont

ecou

lant

and

Han

no. T

he fl

oode

d cr

ater

s be

twee

n V

allis

Rhe

ita

and

crat

er H

anno

are

par

t of t

he A

ustr

ale

Bas

in. E

ject

a fr

om th

atba

sin

prob

ably

und

erlie

s th

e re

gion

of

this

pho

to b

ut h

asbe

en o

verl

ain

wit

h N

ecta

ris

ejec

ta. T

he h

igh

brig

htne

ss in

the

uppe

r ri

ght c

orne

r of

this

imag

e is

an

arti

fact

.

LO4-

064H

1Su

n El

evat

ion:

22.

5°A

ltit

ude:

297

2.87

km

18

5N

ecta

ris

Ba

sin R

egio

n

18

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s ar

ea is

cov

ered

wit

h th

e Ja

nsse

n Fo

rmat

ion,

eje

cta

from

Nec

tari

s. V

allis

Rhe

ita,

for

med

by

the

impa

ct o

f a

chai

n of

seco

ndar

y im

pact

ors

from

the

Nec

tari

s B

asin

, has

exc

avat

edtw

o se

ctor

s of

the

rim

and

the

floo

r of

Pre

-Nec

tari

an c

rate

rY

oung

, bu

t ha

s be

en i

nter

rupt

ed i

n tu

rn b

y th

e yo

unge

rcr

ater

(Y

oung

D).

You

ng D

has

plo

wed

mat

eria

l fr

om t

hew

all o

f Val

lis R

heit

a ac

ross

its

floor

and

ove

r th

e ot

her

side

of

the

valle

y. T

he h

igh

brig

htne

ss i

n th

e up

per

righ

t co

rner

of

this

imag

e is

an

arti

fact

.

LO4-

064H

2Su

n El

evat

ion:

22.

5°A

ltit

ude:

297

2.87

km

The

muc

h-cr

ater

ed m

ain

ring

of

the

Nec

tari

s B

asin

pas

ses

from

Nea

nder

to

the

uppe

r ri

ght

corn

er o

f th

is i

mag

e.Be

twee

n N

eand

er a

nd R

eich

enba

ch th

ere

is a

ligh

t pla

ins

unit

wit

h a

faul

t run

ning

thro

ugh

it in

a d

irec

tion

that

is r

adia

l to

the

near

by M

are

Nec

tari

s. R

eich

enba

ch i

tsel

f ha

s a

ligh

tpl

ains

uni

t on

its

floo

r. T

he g

reat

er b

righ

tnes

s on

the

rig

htsi

de o

f th

is i

mag

e, a

nd t

he fi

ne c

rate

r ch

ains

sou

thw

est

of R

eich

enba

ch,

com

e fr

om n

earb

y St

evin

ius

to t

he e

ast

(LO

4-05

9 in

the

Aus

tral

e B

asin

Reg

ion)

. The

ray

pat

tern

of

Stev

iniu

s m

ay b

e ac

com

pani

ed w

ith

a fin

e ej

ecta

dep

osit

that

form

s lig

ht p

lain

s un

its

in th

is a

rea.

LO4-

064H

3Su

n El

evat

ion:

22.

5°A

ltit

ude:

297

2.87

km

18

7N

ecta

ris

Ba

sin R

egio

n

The

Nec

tari

an c

rate

r B

orda

is

on t

he b

orde

r be

twee

n th

em

ain

ring

of

the

Nec

tari

s B

asin

and

the

tro

ugh

wit

hin

it.

Sant

bech

lies

on

the

mid

dle

ring

sho

wn

in F

igur

e 8.

4 (d

isco

n-ti

nuou

s he

re).

The

trou

gh m

ay h

ave

been

floo

ded

wit

h m

are

in t

his

sect

or (

the

surf

ace

has

been

lig

hten

ed b

y ra

ys f

rom

Stev

iniu

s). I

mbr

ium

dep

osit

s ha

ve la

nded

in t

he t

roug

h an

dpi

led

up a

gain

st t

he m

ain

ring

, blo

ckin

g su

rfac

e la

va fl

ow in

this

are

a.

LO4-

065H

1Su

n El

evat

ion:

23.

8°A

ltit

ude:

273

5.07

km

18

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

Mon

tes

Pyre

naeu

s ra

nge

form

s th

e ea

ster

n se

ctor

of t

hein

nerm

ost

ring

of

the

Nec

tari

s B

asin

and

the

hil

ls s

outh

of

Col

ombo

mar

k th

e m

iddl

e ri

ng o

f Fi

gure

8.3

. R

imae

Goc

leni

us m

ark

typi

cal

radi

al a

nd c

ircu

mfe

rent

ial

frac

ture

sne

ar t

he e

dge

of a

mar

e. I

n th

is c

ase,

the

fau

lts

may

rel

ieve

stre

sses

due

to

both

Mar

e N

ecta

ris

and

Mar

e Fe

cund

itat

is,

whi

ch m

eet

near

the

rig

ht e

dge

of t

his

pict

ure.

Mar

eFe

cund

itat

is is

cov

ered

in t

he c

hapt

er o

n th

e Ea

ster

n B

asin

sR

egio

n (C

hapt

er 1

0).

The

floo

rs o

f G

ocle

nius

and

Mag

el-

haen

s ar

e flo

oded

wit

h la

va, b

ut p

roba

bly

not

from

the

sur

-ro

undi

ng m

are,

bec

ause

the

se fl

oors

are

at

a m

uch

low

erle

vel t

han

the

surr

ound

ing

mar

e.

LO4-

065H

2Su

n El

evat

ion:

23.

8°A

ltit

ude:

273

5.07

km

18

9N

ecta

ris

Ba

sin R

egio

n

Thi

s im

age

is p

artl

y fo

gged

, ap

pare

ntly

by

grou

nd p

ro-

cess

ing,

as

LO4-

065H

2 w

as n

ot a

ffec

ted.

Mar

e Fe

cund

itat

isin

trud

es o

n th

e N

ecta

ris

Bas

in n

ear

Gut

enbe

rg, a

nd p

art

ofM

are

Tra

nqui

llita

tis

appe

ars

near

the

nort

hwes

tern

cor

ner

ofth

e ph

oto.

A t

ripl

e in

ters

ecti

on o

f th

e m

ain

ring

s of

the

Nec

tari

s, F

ecun

dita

tis,

and

Tra

nqui

llita

tis

Bas

ins

lifts

the

Cen

sori

nus

plat

eau,

who

se e

aste

rn e

dge

can

be s

een

abou

t10

0 km

dow

n fr

om th

e to

p of

this

pho

to, a

long

the

left

-han

ded

ge. S

ee L

O4-

072

H3

for

a fu

ll vi

ew o

f th

is i

nter

esti

ng p

la-

teau

. The

Tra

nqui

llita

tis

Bas

in i

s co

vere

d in

the

cha

pter

on

the

Sere

nita

tis

Bas

in R

egio

n (C

hapt

er 9

).

LO4-

065H

3Su

n El

evat

ion:

23.

8°A

ltit

ude:

273

5.07

km

19

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

mai

n ri

ng o

f the

anc

ient

, deg

rade

d A

ustr

ale

Bas

in p

asse

sth

roug

h H

anno

, bou

ndin

g th

e ea

ster

n pa

rt o

f Mar

e A

ustr

ale.

Sign

s of

eas

t-w

est

ridg

es a

nd v

alle

ys r

adia

l to

Aus

tral

e ha

vebe

en e

rase

d by

lat

er d

epos

its.

The

dep

ress

ion

sout

hwes

t of

Bri

sban

e an

d th

e N

ecta

rian

cra

ter

Pont

ecou

lant

lie

in

anou

ter

trou

gh o

f th

e A

ustr

ale

Bas

in.

Cra

ter

Bri

sban

e w

asna

med

for

ast

rono

mer

Sir

Tho

mas

Bri

sban

e, a

Sco

t w

hose

rved

as

gove

rnor

of

New

Sou

th W

ales

in

Aus

tral

ia b

efor

ees

tabl

ishi

ng o

bser

vato

ries

in A

ustr

alia

and

Sco

tlan

d.

LO4-

059H

1Su

n El

evat

ion:

21.

7°A

ltit

ude:

297

4.56

km

19

1N

ecta

ris

Ba

sin R

egio

n

Val

lis R

heit

a an

d th

e ot

her

chai

ns o

f lar

ge s

econ

dary

cra

ters

radi

ate

from

the

Nec

tari

s B

asin

. In

the

are

a ne

ar P

re-

Nec

tari

an V

ega,

abo

ut o

ne b

asin

rad

ius

from

the

mai

n ri

ngof

Nec

tari

s, t

he h

eavy

Jan

ssen

For

mat

ion

give

s w

ay t

o fie

lds

of s

econ

dary

cra

ters

.

LO4-

059H

2Su

n El

evat

ion:

21.

7°A

ltit

ude:

297

4.56

km

19

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

059H

3Su

n El

evat

ion:

21.

7°A

ltit

ude:

297

4.56

km

19

3N

ecta

ris

Ba

sin R

egio

n

The

bri

ghtn

ess

in th

is a

rea

com

es fr

om a

20-

km c

rate

r ab

out

70 k

m s

outh

east

of

the

rim

of

Stev

inus

and

a 5

-km

cra

ter

abou

t 35

km

nor

thea

st o

f th

e ri

m o

f St

evin

us,

as w

ell

asSt

evin

us it

self.

Ste

vinu

s ha

s be

en a

ssig

ned

to th

e C

oper

nica

nPe

riod

bec

ause

of

its

fres

h, s

harp

app

eara

nce.

Com

pare

its

shar

pnes

s w

ith

the

35-k

m E

rato

sthe

nian

cra

ter

nort

h of

Rei

chen

bach

(ca

lled

Rie

chen

bach

A).

The

eje

cta

blan

ket

from

the

sm

alle

r cr

ater

has

los

t it

s de

tail

. T

he v

ery

long

Val

lis S

nelli

us (

radi

al to

the

Nec

tari

s B

asin

) co

ntin

ues

to th

eso

uthe

ast

tow

ard

the

Aus

tral

e B

asin

, be

com

ing

muc

h le

ssdi

stin

ct. T

here

may

act

ually

be

two

valle

ys (

one

from

eac

hba

sin)

tha

t ap

prox

imat

ely

mee

t. T

he r

idge

and

val

ley

that

com

es

from

th

e no

rth-

nort

hwes

t,

cont

inui

ng

beyo

ndSt

evin

us, i

s ra

dial

to th

e Fe

cund

itat

is B

asin

.

Messier and its companion to the west(called Messier A) are characteristic inshape to low-angle (about 5° from thehorizontal) impacts of a lower-densitymaterial into a higher-density material.Messier A may actually have been causedby a pair of impactors. The ray pattern ofthese Copernican craters takes threedirections: to the left and right of theimpact axis and downstream. Except forthe few surface features, this area showsa deep mare lava floor fed by a pluton ofrising lava from the mantle.

The southern part of Mare Fecun-ditatis (east of Monge and Cook) hasprobably flooded an intersection oftroughs (LO4-060H1). The main ring ofthe Fecunditatis Basin passes throughthe low ridge between Crozier andMcClure.

This area of Mare Fecunditatis mayhave flooded a depression formed bythe intersection of troughs from theFecunditatis, Nectaris, and Balmer-Kapteyn Basins. The main ring of theNectaris Basin passes through Bordaand runs west of Biot. Vallis Snellius isradial to the Nectaris Basin.

19

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

In t

he l

ower

rig

ht h

alf

of t

his

pict

ure

is a

sha

llow

are

a of

Mar

e A

ustr

ale,

the

nor

thw

est

sect

or o

f th

e pa

rtia

lly fl

oode

dba

sin.

Cra

ters

onl

y a

few

kilo

met

ers

acro

ss,

and

ther

efor

eon

ly h

undr

eds

of m

eter

s de

ep, a

re o

nly

part

ially

floo

ded

The

mai

n ri

ng o

f th

e an

cien

t, d

egra

ded

Aus

tral

e B

asin

pas

ses

thro

ugh

Han

no, b

ound

ing

the

east

ern

part

of M

are

Aus

tral

e.La

ter

depo

sits

hav

e er

ased

mos

t sig

ns o

f Aus

tral

e ej

ecta

. The

depr

essi

on s

outh

wes

t of

Bri

sban

e an

d th

e N

ecta

rian

cra

ter

Pont

ecou

lant

lies

in a

n ou

ter

trou

gh o

f the

Aus

tral

e B

asin

.

LO4-

052H

1Su

n El

evat

ion:

23.

1°A

ltit

ude:

297

6.44

km

19

5N

ecta

ris

Ba

sin R

egio

n

An

inte

rrup

tion

of

tran

smis

sion

bet

wee

n th

e sp

acec

raft

and

Eart

h re

sult

ed i

n th

e lo

ss o

f m

ost

of s

ubfr

ame

LO4-

052H

3.T

he s

ix fr

amel

ets

that

hav

e be

en r

ecei

ved

have

bee

n ad

ded

toth

e to

p of

LO

4-05

2H2

in t

his

mos

aic.

Cha

ins

of s

econ

dary

crat

ers

in th

is a

rea

radi

ate

from

the

Nec

tari

s B

asin

. Veg

a an

dth

e cr

ater

s w

ithi

n it

are

cle

arly

Pre

-Nec

tari

an b

ecau

se t

heva

lleys

alig

ned

wit

h th

e cr

ater

cha

ins

scar

them

all.

Fur

neri

usis

a P

re-N

ecta

rian

cra

ter;

bes

ides

bei

ng f

ract

ured

, it

is o

ver-

lain

wit

h ej

ecta

from

Nec

tari

s.

LO4-

052H

2 Su

n El

evat

ion:

23.

1°A

ltit

ude:

297

6.44

km

and

-H3

19

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Peta

vius

is

a “p

oste

r ch

ild”

of f

ract

ured

-floo

r cr

ater

s. I

t is

larg

e en

ough

to h

ave

a pr

omin

ent c

entr

al p

eak

of s

ome

com

-pl

exit

y an

d a

heig

ht o

f 3.5

km

abo

ve th

e cr

ater

floo

r. In

add

i-ti

on, R

imae

Pet

aviu

s re

veal

fra

ctur

es t

hat

seem

lar

ger

than

can

be e

xpla

ined

by

cool

ing

and

mor

e lik

ely

to r

eflec

t str

ong

uplif

t fo

rces

act

ing

on a

mel

t sh

eet.

The

upw

ard

pres

sure

may

be

rela

ted

to th

e la

va fl

oodi

ng th

e ne

arby

sou

ther

n pa

rtof

Mar

e Fe

cund

itat

is, t

o th

e up

per

left

in th

e ph

oto.

The

dar

kar

eas

near

the

wal

ls o

f Pe

tavi

us s

ugge

st t

he r

elea

se o

f da

rkgl

ass

part

icle

s (d

ark

man

tlin

g m

ater

ials

) fr

om f

ount

ains

driv

en b

y th

e re

leas

e of

vol

atile

s. C

rate

r co

unts

hav

e re

sult

edin

Pet

aviu

s be

ing

assi

gned

to th

e Ea

rly

Imbr

ian

Epoc

h.

LO4-

053H

1Su

n El

evat

ion:

23.

3°A

ltit

ude:

273

7.76

km

19

7N

ecta

ris

Ba

sin R

egio

n

The

mai

n ri

ng o

f the

Fec

undi

tati

s B

asin

can

be

seen

ent

erin

gth

is i

mag

e ju

st n

orth

of

15°

sout

h la

titu

de a

nd c

urvi

ngto

war

d La

ngre

nus

in t

he u

pper

rig

ht c

orne

r. T

his

ring

may

have

bee

n su

bseq

uent

ly d

estr

oyed

by

the

impa

ct o

f on

e or

mor

e pr

imar

y ob

ject

s, a

llow

ing

join

t flo

odin

g by

mar

e la

va.

Lang

renu

s, v

ario

usly

ass

igne

d to

the

you

nger

Era

tost

heni

anPe

riod

or

the

olde

r pa

rt o

f th

e C

oper

nica

n Pe

riod

, ha

s a

mod

est

set

of r

ays

for

such

a la

rge

crat

er. T

he 3

5-km

cra

ter

near

the

bott

om o

f thi

s im

age

(and

the

top

of L

O4-

053H

1) is

mor

e cl

earl

y C

oper

nica

n, w

ith

a th

ree-

pron

ged

ray

syst

emty

pica

l of

a p

rim

ary

crat

er t

hat

has

appr

oach

ed f

rom

the

nort

h w

ith

a lo

w a

ngle

. Ven

delin

us a

nd L

ohse

may

be

in a

trou

gh o

f the

Bal

mer

-Kap

teyn

Bas

in (

see

Cha

pter

10)

, whi

chw

ould

influ

ence

thei

r be

ing

flood

ed w

ith

lava

.

LO4-

053H

2Su

n El

evat

ion:

23.

3°A

ltit

ude:

273

7.76

km

19

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

suc

cess

ful

land

ing

of L

una

16 i

s di

scus

sed

in t

hech

apte

r on

the

Ser

enit

atis

Bas

in R

egio

n (

LO4-

054H

1)(C

hapt

er 9

). T

his

phot

o co

vers

the

dee

pest

par

t of

Mar

eFe

cun

dita

tis

(the

cen

ter

of t

he F

ecun

dita

tis

Bas

in i

s at

4°

S an

d 52

°E

). A

ric

h fie

ld o

f ej

ecta

an

d se

con

dari

es

from

Lan

gren

us h

as c

over

ed t

he m

are

floor

, es

tabl

ishi

ngLa

ngre

nus

as e

ithe

r Er

atos

then

ian

or C

oper

nica

n. T

hem

odes

t ray

sys

tem

(fo

r su

ch a

larg

e cr

ater

) pl

aces

its

age

near

the

bord

er b

etw

een

thos

e tw

o pe

riod

s. B

ilhar

z, N

aono

bu, a

ndA

twoo

d, fo

rmed

by

thre

e im

pact

ors

that

may

hav

e la

nded

ina

salv

o, a

re o

lder

than

the

mar

e flo

or b

ut a

re c

lear

ly y

oung

erth

an L

angr

enus

. A

s in

oth

er m

aria

, a

few

wri

nkle

rid

ges

(dor

sa)

appe

ar o

n it

s su

rfac

e. N

orth

ern

Mar

e Fe

cund

itat

isco

ntin

ues

into

the

Ser

enit

atis

Bas

in R

egio

n. T

he e

aste

rnsh

ore

can

be fo

und

in th

e Ea

ster

n B

asin

s R

egio

n.

LO4-

053H

3Su

n El

evat

ion:

23.

3°A

ltit

ude:

273

7.76

km

19

9N

ecta

ris

Ba

sin R

egio

n

9.1. OverviewThe Serenitatis Basin Region stretches from Mare Imbrium,whose eastern edge is near the 0° meridian, across MareSerenitatis and Mare Tranquillitatis to the western edge ofMare Crisium.

A series of four basins, Imbrium, Serenitatis, Tranquillitatis,and Fecunditatis, cover an arc of 120°, one-third of the cir-cumference of the Moon. Each member of this chain of basins

has formed a circular depression that was subsequently (longafter the impact event) filled with lava erupted from below,forming a mare. The Fecunditatis Basin, whose edge is visiblein the lower right-hand corner of Figure 9.1, is covered in theNectaris Basin Region (see Chapter 8).

The diameters of the main rings of these four basins(Spudis, 1993) are as follows:

● Imbrium: 1160 km● Serenitatis: 920 km

Chapter 9

Serenitatis Basin Region

Figure 9.1. LO4-097M: Serenitatis Basin Region. The Imbrium, Serenitatis, and Tranquillitatis Basins underlie their respective maria. Sinus Aestuum lies inan outer trough of the Imbrium Basin, and Mare Vaporum lies in a depression formed by the intersection of outer troughs of the Imbrium and SerenitatisBasins. Mare Frigoris lies partly in the northern part of the same outer trough of the Imbrium Basin as Sinus Aestuum and Mare Vaporum.

20

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

● Tranquillitatis: 700 km● Fecunditatis: 690 km

To provide a sense of scale, Spain and Portugal would be aclose fit in Mare Serenitatis. Massive mountain ranges werethrown up at arcs of the main ring of these basins, especiallywhere the main rings of two or more basins come together.For example, at the boundary between the Imbrium andSerenitatis Basins, Montes Apenninus (to the south) rise asmuch as 4,430 m (14,400 feet) above the nearby mare surface.Radial ridges formed by ejecta from the Imbrium event canbe seen south of Mare Serenitatis, running for 500 km. Suchranges and ridges are formed by impact in a matter ofminutes and hours.

Serenitatis BasinMare Serenitatis is unusual in that it has apparently coveredtwo basins: the Serenitatis Basin and an older, smaller basinnorth-northeast of the main Serenitatis Basin called theNorthern Serenitatis Basin. The main ring of the SerenitatisBasin is interrupted in the sector where it would havecrossed the floor of the older basin, perhaps suppressed by amelt sheet within the main ring of that basin. Similarly, themelt sheet of the Serenitatis Basin may have suppressed themain ring of the younger Imbrium Basin where it would havecrossed the floor of the Serenitatis Basin. In the same way,the melt sheet of the Tranquillitatis Basin may have sup-pressed the main ring of the Serenitatis Basin where theyintersect.

Apollo LandingsApollo 11 landed on Mare Tranquillitatis (LO4-085H1), thefirst landing of humans beyond Earth and the first mission toreturn rock samples from beyond Earth. The samples col-lected by Armstrong and Aldrin established many of thecharacteristics confirmed by subsequent missions. The rockswere composed of basalt, a complex material that hardensfrom lava flows when molten rock from the mantle (theregion of relatively dense rock below a crust) rises to thesurface. On Earth, basalt paves the floors of the oceans anderupts from volcanoes. The lunar soil and rocks are free oforganic compounds and of volatile elements and compounds(hydrogen, sulfur, sodium, and water). The age of the basaltat Tranquillitatis Base was found to be 3.65 aeons (billionyears).

A few rock samples were not basalt but had been thrownfrom highlands by impacts. These rocks contain plagioclase,a low-density mineral composed of calcium and aluminumsilicates. This is the material, along with other minerals thatcombine easily with it, that rises from a body of molten rock(the magma ocean of the primitive Moon) to form the crust.

Apollo 15 landed near the sinuous canyon of Rima Hadleyand Mons Hadley, a mountain in the Montes Apenninusrange, part of the main ring of the Imbrium Basin (LO4-102H3). Equipped with a Lunar Roving Vehicle, Scott andIrwin explored a wide variety of terrain types. The walls ofRima Hadley showed layers of mare material from a series offlows; the deepest flow was 60 m in depth. “Genesis Rock,” acrustal rock aged at 4.15 billion years, was collected from theslope below the mountain Hadley Delta. Some samples, richin highland plagioclase, were probably thrown to this areafrom the crater Autolycus from 150 km away; the impactevent was aged at 1.29 million years.

Apollo 17 landed in a valley (Taurus-Littrow Valley) ofMontes Taurus, part of the main ring of the SerenitatisBasin (LO4-078H3). Schmitt and Cernan, their travels aidedby a Lunar Roving Vehicle, sampled ejecta from theSerenitatis Basin. Radioactive aging of the samples estab-lished the age of the Serenitatis Basin to be 3.86 or 3.87 billion years. One-meter layers of orange and blackglass beads were discovered, establishing the character ofdark mantling material that is common near the edges ofmaria. Some samples of material from a ray of Tycho weredated at 109 million years.

9.2. High-Resolution ImagesTable 9.1 shows the high-resolution images of the SerenitatisBasin Region in schematic form.

The following pages show the high-resolution subframesfrom south to north and west to east. That is, they are in theorder LO4-102H1, LO4-102H2, LO4-102H3, LO4-103H1,LO4-103H2 … LO4-054H1, LO4-054H2… LO4-055H3.

Subframes LO4-098H3, LO4-086H3, LO4-074H3, and LO4-062H3 are redundant and are not printed, although they areincluded in the enclosed CD.

Photos LO4-078H, LO4-073H, LO4-066H, and LO4-054Hare printed as complete frames.

20

1Se

renita

tis

Ba

sin R

egio

n

56 N–90 N 104 092 080 068 191H1

27 N–56 N 110 103 098 091 086 079 074 067 062 055 191H2

0–27 N 109 102 097 090 085 078 073 066 061 054 191H3

0–27 S 108 101 096 089 084 077 072 065 060 053 046

Longitude 3 W 4 E 10 E 16 E 24 E 30 E 38 E 43 E 49 E 57 E 63 Eat Equator

Table 9.1. The cells shown in white represent the high-resolution photos of the Serenitatis Basin Region (LO4-XXX H1, -H2, and -H3, where XXX is thePhoto Number). The Imbrium Basin Region is to the west, the Nectaris Basin Region is to the south, the Eastern Basins Region is to the west, and the NorthPolar Region is to the north.

Surv

eyor

s 4

and

6 ar

e di

scus

sed

in t

he n

ote

for

LO4-

108H

3, in

the

Hum

orum

Bas

in R

egio

n. T

he c

ompl

ex p

atte

rn o

f Rim

ae T

ries

neck

er r

eflec

ts s

tret

chin

g of

the

surf

ace

of S

inus

Med

ii aw

ay fr

om it

s bo

rder

as

lava

coo

led.

The

last

maj

orflo

w o

f lav

a ca

me

from

the

east

, as

indi

cate

d by

the

scar

p th

at r

uns

nort

h fr

omR

eaum

ur a

nd c

onti

nues

pas

t B

lagg

. A l

arge

pos

itiv

e gr

avit

y an

omal

y in

the

Cle

men

tine

dat

a, c

ente

red

abou

t 50

km

nor

thea

st o

f th

e ea

rly

Cop

erni

can

crat

er T

ries

neck

er, m

ay m

ark

the

sour

ce o

f th

e flo

w. T

he r

idge

s an

d va

lleys

are

Fra

Mau

ro F

orm

atio

n, e

ject

a fr

om t

he I

mbr

ium

Bas

in w

hose

mai

n ri

ng is

abou

t a

radi

us a

way

. A d

etai

led

exam

inat

ion

of M

urch

ison

ind

icat

es t

hat

its

floor

has

bee

n flo

oded

from

nea

r it

s w

alls

.

20

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

102H

1Su

n El

evat

ion:

21.

6°A

ltit

ude:

269

9.13

km

Mar

e V

apor

um, s

outh

of t

he fo

othi

lls o

f the

Mon

tes

Ape

nnin

us, h

as fi

lled

the

trou

gh o

utsi

de t

he m

ain

ring

of

the

Imbr

ium

Bas

in. I

ts s

outh

ern

boun

dary

isth

e lo

wer

hill

s of

the

nex

t ou

ter

ring

of

the

Imbr

ium

Bas

in, 1

700

km i

n di

a-m

eter

. The

nea

rest

gra

vity

ano

mal

y in

Cle

men

tine

dat

a th

at c

ould

mar

k th

eso

urce

of t

he la

va is

nea

r T

ries

neck

er (

LO4-

102H

1) to

the

sout

h. R

ima

Hyg

inus

may

be

a co

llaps

ed l

ava

tube

tha

t ra

n to

the

nor

thw

est

to h

elp

form

Mar

eV

apor

um. T

he c

rate

rs a

long

Rim

a H

ygin

us, n

otab

le fo

r th

eir

lack

of r

ims,

may

have

bee

n in

divi

dual

col

laps

e ev

ents

. Hyg

inus

its

elf,

a ri

mle

ss c

rate

r w

ith

ada

rk h

alo,

may

hav

e be

en a

n en

doge

nic

sour

ce fo

r so

me

of th

e la

va c

arri

ed b

yth

e tu

be.

20

3Se

renita

tis

Ba

sin R

egio

n

LO4-

102H

2Su

n El

evat

ion:

21.

6°A

ltit

ude:

269

9.13

km

The

land

ing

site

for

Apo

llo 1

5, P

alus

Put

redi

nis

(“Sw

amp

of D

ecay

”) n

ear

the

edge

of

Mar

e Im

briu

m, w

as c

hose

n fo

r th

e op

port

unit

y to

exp

lore

bot

h hi

gh-

land

s fo

rmed

by

the

mai

n ri

ng o

f the

Imbr

ium

Bas

in a

nd th

e de

ep c

ut th

roug

hm

are

mat

eria

l of R

ima

Had

ley.

As

in o

ther

bas

in r

ims,

ris

ing

lava

see

ms

to b

ebl

ocke

d by

a m

assi

ve r

im r

ange

, flow

ing

out t

hrou

gh a

ven

t and

dow

n th

e si

deof

the

ran

ge.

Onc

e it

rea

ches

the

flat

ter

terr

ain

of P

alus

Put

redi

nus,

Rim

aH

adle

y (l

ike

Val

lis S

chro

teri

) m

eand

ers

like

terr

estr

ial

rive

rs i

n ne

arly

flat

land

. The

ast

rona

uts

saw

laye

rs in

the

wal

ls o

f Rim

a H

adle

y, in

dica

ting

a s

erie

sof

lava

flow

s. O

ne o

f the

roc

ks s

ampl

ed fr

om th

e sl

ope

of M

ons

Had

ley

delta

isth

e “G

enes

is r

ock,

” co

ntai

ning

whi

te p

lagi

ocla

se. T

his

low

-den

sity

min

eral

isty

pica

l of t

he o

rigi

nal c

rust

form

ed 4

.5 b

illio

n ye

ars

ago.

How

ever

, it

appe

ars

to h

ave

been

sho

cked

and

rec

ryst

alliz

ed b

y an

im

pact

, res

etti

ng i

ts “

atom

iccl

ock”

so

that

its

mea

sure

d ag

e is

4.1

5 bi

llion

yea

rs.

20

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

102H

3Su

n El

evat

ion:

21.

6°A

ltit

ude:

269

9.13

km

See

LO4-

102H

3 fo

r no

tes

on t

he A

pollo

15

land

ing

site

. The

bubb

ly d

evel

opm

ent

arti

fact

lie

s al

ong

a “s

trai

t” o

f m

are

mat

eria

l th

at c

onne

cts

Mar

e Im

briu

m (

left

) w

ith

Mar

eSe

reni

tati

s (r

ight

). I

n th

is a

rea,

the

Im

briu

m m

ain

ring

,m

arke

d by

Mon

tes

Ape

nnin

us a

nd M

onte

s C

auca

sus,

cro

sses

insi

de o

f th

e m

ain

ring

of

Sere

nita

tis.

A m

elt

shee

t th

ere

may

hav

e in

hibi

ted

form

atio

n of

mou

ntai

ns i

n th

e st

rait

.A

ltho

ugh

the

Sere

nita

tis

Bas

in w

as f

orm

ed b

efor

e th

eIm

briu

m B

asin

, the

last

maj

or m

are

flow

see

ms

to h

ave

been

from

Ser

enit

atis

, as

show

n by

the

scar

p th

at r

uns

nort

h fr

omPr

omon

tori

um F

resn

el.

LO4-

103H

1Su

n El

evat

ion:

22.

3°A

ltit

ude:

292

6.55

km

20

5Se

renita

tis

Ba

sin R

egio

n

The

hum

moc

ky (

bum

py)

area

in

the

uppe

r le

ft q

uadr

ant

ofth

is p

hoto

is

the

Alp

es F

orm

atio

n of

the

Im

briu

m B

asin

,si

mila

r to

the

Mon

tes

Roo

k Fo

rmat

ion

of th

e O

rien

tale

Bas

in.

Thi

s ar

ea i

s be

twee

n th

e m

ain

ring

of

the

Imbr

ium

Bas

in(M

onte

s C

auca

sus)

and

an

inne

r ri

ng.

Eudo

xus

is f

resh

look

ing

and

show

s no

sig

n of

bei

ng a

ffec

ted

by e

ject

a fr

omth

e la

rge

crat

er A

rist

otel

es ju

st to

the

nort

h (L

O4-

103H

3), s

oit

is

prob

ably

Cop

erni

can.

Ale

xand

er f

orm

ed b

efor

e th

eIm

briu

m B

asin

; it

is

over

lain

wit

h Im

briu

m s

tria

tion

s.C

assi

ni h

as o

ccur

red

afte

r th

e Im

briu

m B

asin

was

form

ed, o

rit

wou

ld h

ave

been

obl

iter

ated

. Sub

sequ

entl

y flo

oded

by

one

of t

he fi

rst

lava

flow

s in

Mar

e Im

briu

m, i

t is

ass

igne

d to

the

Earl

y Im

bria

n Pe

riod

.

LO4-

103H

2Su

n El

evat

ion:

22.

3°A

ltit

ude:

292

6.55

km

20

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

Era

tost

heni

an c

rate

r A

rist

otel

es (

87 k

m)

prov

ides

an

ex-

celle

nt e

xam

ple

of th

e ej

ecta

pat

tern

of a

cra

ter

of th

is s

ize.

Ahe

avy

ejec

ta b

lank

et w

ith

radi

al r

idge

s ex

tend

s be

yond

the

rim

to

a di

stan

ce o

f ab

out

one

rim

rad

ius.

Bey

ond

that

, the

thin

ning

eje

cta

beco

mes

an

arra

y of

sec

onda

ry i

mpa

ctor

s,w

hich

oft

en fo

rm c

hain

s of

cra

ters

. Gal

le h

as a

ppar

entl

y ha

da

gap

in i

ts n

orth

ern

rim

inv

aded

by

mar

e la

va, w

hich

cas

-ca

ded

to i

ts fl

oor

in o

ne o

r po

ssib

ly t

wo

epis

odes

. The

lav

aflo

w(s

) m

ust h

ave

been

the

last

flow

s in

the

area

, or

the

crat

erw

ould

hav

e be

en c

ompl

etel

y in

unda

ted.

The

mar

e ar

ea i

spa

rt o

f Mar

e Fr

igor

is. I

n th

is a

rea,

it h

as fo

rmed

in a

n in

ter-

sect

ion

of th

e fir

st o

uter

trou

gh o

f the

Imbr

ium

Bas

in a

nd th

efir

st o

uter

trou

gh o

f the

Nor

ther

n Se

reni

tati

s B

asin

.

LO4-

103H

3Su

n El

evat

ion:

22.

3°A

ltit

ude:

292

6.55

km

20

7Se

renita

tis

Ba

sin R

egio

n

The

str

iate

d ri

dges

of

the

Fra

Mau

ro F

orm

atio

n fr

omIm

briu

m h

ave

impa

cted

rug

ged

high

land

s ab

out

one

radi

usaw

ay fr

om th

e m

ain

ring

of I

mbr

ium

. Rim

ae T

ries

neck

er a

rein

terl

ocki

ng r

adia

l an

d ci

rcum

fere

ntia

l st

ress

fau

lts

at t

heed

ge o

f M

are

Vap

orum

. T

he C

oper

nica

n cr

ater

God

in h

asse

nt i

ts e

ject

a bl

anke

t ov

er t

hat

of t

he E

rato

sthe

nian

cra

ter

Agr

ippa

, whi

ch i

n tu

rn, a

long

wit

h Im

briu

m, i

mpa

cted

the

anci

ent

crat

er T

empe

l. T

he fl

oor

of L

ade

is c

over

ed w

ith

hum

moc

ky m

ater

ial

that

may

hav

e be

en e

ject

ed f

rom

Imbr

ium

and

bee

n de

cele

rate

d by

gla

ncin

g of

f th

e ri

m o

fLa

de.

Som

e of

thi

s m

ater

ial

may

be

from

the

rim

its

elf.

Nor

thea

st o

f R

haet

icus

, th

ere

is a

cha

in o

f fr

esh-

look

ing

seco

ndar

y cr

ater

s th

at is

rad

ial t

o O

rien

tale

.

20

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

097H

1Su

n El

evat

ion:

21.

6°A

ltit

ude:

270

5.28

km

Mon

tes

Hae

mus

mar

ks t

he m

ain

ring

of

the

Sere

nita

tis

Bas

in. T

his

area

of

Mar

e V

apor

um f

orm

ed in

the

firs

t ou

ter

trou

gh o

f the

Ser

enit

atis

Bas

in, a

long

wit

h La

cus

Gau

dii a

ndLa

cus

Leni

tati

s. O

nce

thou

ght

to b

e vo

lcan

ic, t

he e

long

ated

form

atio

n ne

ar B

osco

vich

is n

ow c

onsi

dere

d to

be

a ch

ain

ofse

cond

ary

crat

ers

from

an

earl

y st

age

of th

e Im

briu

m im

pact

,m

odifi

ed b

y an

eje

cta

flow

from

the

sam

e im

pact

. The

se t

wo

stag

es w

ould

hav

e be

en s

epar

ated

in

tim

e by

onl

y a

few

min

utes

. Fl

oodi

ng b

y m

are

wou

ld h

ave

been

mil

lion

s of

year

s la

ter.

Ope

ning

of

the

stre

ss c

rack

s un

der

Rim

aeB

osco

vich

wou

ld h

ave

been

sti

ll la

ter.

Man

ilius

is c

onsi

dere

dto

be

of t

he L

ate

Imbr

ian

Epoc

h be

caus

e it

s ej

ecta

ove

rlie

sth

e m

are.

LO4-

097H

2Su

n El

evat

ion:

21.

6°A

ltit

ude:

270

5.28

km

20

9Se

renita

tis

Ba

sin R

egio

n

At t

he b

orde

r of

Mar

e Se

reni

tati

s, b

etw

een

Joy

and

Sulp

iciu

sG

allu

s, is

a d

epos

it th

at d

arke

ns th

e m

are,

the

bum

py te

rrai

nbe

twee

n M

onte

s H

aem

us a

nd t

he m

are

(Alp

es F

orm

atio

n;se

e th

e no

te fo

r LO

4-10

3H2)

, and

Lac

us O

dii.

Thi

s de

posi

t is

char

acte

rize

d as

dar

k m

antl

ing

mat

eria

l, a

type

that

is fo

und

on t

he b

orde

r of

oth

er m

aria

. It

may

be

due

to “

fire-

foun

tain

” vo

lcan

ic e

rupt

ions

fro

m d

epth

or

poss

ibly

res

ult

from

vol

atile

s re

leas

ed w

here

a t

hin

laye

r of

lava

flow

s ov

ercr

usta

l m

ater

ial.

Cir

cum

fere

ntia

l ri

dges

suc

h as

Dor

sum

Buc

klan

d an

d D

orsu

m G

ast

and

frac

ture

s su

ch a

s R

imae

Sulp

iciu

s G

allu

s ar

e co

mm

on a

t th

e ed

ges

of m

aria

. Lin

ne is

a

Cop

erni

can

crat

er t

hat

has

impa

cted

Mar

e Se

reni

tati

s. A

chai

n of

suc

h cr

ater

s m

arch

es a

cros

s th

e ed

ge o

f M

are

Sere

nita

tis

into

Mon

tes

Hae

mus

.

21

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

097H

3Su

n El

evat

ion:

21.

6°A

ltit

ude:

270

5.28

km

The

pro

ject

ion

in th

e lo

wer

left

of t

he p

hoto

mar

ks th

e in

ters

ecti

on o

f the

mai

nri

ng o

f th

e Se

reni

tati

s B

asin

wit

h th

at o

f th

e N

orth

ern

Sere

nita

tis

Bas

in. T

hese

ctio

n of

the

Mon

tes

Cau

casu

s in

the

upp

er l

eft

corn

er o

f th

is p

hoto

is

the

mai

n ri

ng o

f the

Nor

ther

n Se

reni

tati

s B

asin

. Mar

e Se

reni

tati

s sh

ows

few

indi

-

cati

ons

of d

row

ned

crat

ers,

exc

ept

for

som

e fa

int

circ

ular

rid

ges,

ind

icat

ing

that

the

mar

e is

dee

p. T

here

is

a st

rong

mas

con

asso

ciat

ed w

ith

Mar

eSe

reni

tati

s, i

ndic

atin

g th

at a

lar

ge p

lum

e of

lav

a fr

om t

he m

antl

e fe

d th

eflo

odin

g of

the

over

lapp

ing

pair

of b

asin

s.

21

1Se

renita

tis

Ba

sin R

egio

n

LO4-

098H

1Su

n El

evat

ion:

22.

3°A

ltit

ude:

292

6.55

km

In t

his

area

nor

th o

f M

are

Sere

nita

tis

ther

e ar

e ov

erla

ppin

g de

posi

ts e

ject

edfr

om t

he S

eren

itat

is,

Nor

ther

n Se

reni

tati

s, a

nd I

mbr

ium

Bas

ins

(wit

h th

eIm

briu

m e

ject

a up

perm

ost)

. Bec

ause

of i

ts h

umm

ocky

cha

ract

er, i

t is

map

ped

as a

n ex

tens

ion

of th

e A

lpes

For

mat

ion

of th

e Im

briu

m B

asin

. How

ever

, it m

ayha

ve a

dif

fere

nt fo

rmin

g m

echa

nism

than

the

area

insi

de o

f the

Im

briu

m r

im.

The

por

tion

sou

th o

f 40°

nort

h la

titu

de m

ay b

e pr

imar

ily N

orth

ern

Sere

nita

tis

mat

eria

l w

ithi

n it

s ri

m,

and

the

nort

hern

por

tion

may

not

rea

lly b

e “h

um-

moc

ky”;

it

may

be

sim

ply

cros

shat

ched

wit

h st

riat

ions

fro

m I

mbr

ium

and

Sere

nita

tis.

21

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

098H

2Su

n El

evat

ion:

22.

3°A

ltit

ude:

292

6.55

km

In m

any

part

s of

the

Moo

n, th

ere

are

smal

l pat

ches

of s

moo

th p

lain

s in

oth

er-

wis

e ru

gged

hig

hlan

d re

gion

s si

mila

r to

thi

s ar

ea s

urro

undi

ng C

ayle

y, t

hear

chet

ype

of th

e C

ayle

y Fo

rmat

ion.

The

se r

egio

ns a

re a

ssoc

iate

d w

ith

the

oute

rej

ecta

bla

nket

fro

m m

ajor

bas

ins

such

as

Imbr

ium

, Ori

enta

le, a

nd N

ecta

ris.

The

se h

ighl

and

plai

ns m

ay r

esul

t fr

om r

elat

ivel

y un

ifor

m b

lank

ets

of fi

nely

pulv

eriz

ed e

ject

a th

at a

re s

hake

n do

wn

by lo

cal t

ecto

nic

forc

es. T

o qu

ote

Ken

Mat

ting

ly, t

he C

omm

and

Mod

ule

Pilo

t for

Apo

llo 1

6, “

The

Cay

ley

repr

esen

ts a

pool

of

unco

nsol

idat

ed m

ater

ial

whi

ch h

as b

een

‘sha

ken’

unt

il th

e su

rfac

e is

rela

tive

ly fl

at.”

Rim

a A

riad

aeus

, a

larg

e fa

ult

wit

h an

off

set,

may

ind

icat

est

rong

tect

onic

act

ion

in th

is a

rea

arou

nd C

ayle

y.

21

3Se

renita

tis

Ba

sin R

egio

n

LO4-

090H

1Su

n El

evat

ion:

21.

6°A

ltit

ude:

271

1.26

km

Thi

s in

tere

stin

g re

gion

sou

th o

f M

are

Sere

nita

tis

show

s M

onte

s H

aem

us, t

heso

uthe

rn m

ain

ring

of

the

Sere

nita

tis

Bas

in, i

mpa

cted

by

stri

atio

ns f

rom

the

Imbr

ium

Bas

in. T

he o

uter

trou

gh o

f the

Ser

enit

atis

Bas

in h

as b

een

flood

ed b

yLa

cus

Gau

dii,

Lacu

s H

iem

alis

, La

cus

Leni

tati

s, a

nd S

inus

Hon

oris

. M

are

Tra

nqui

llita

tis

is t

o th

e so

uthe

ast

of S

inus

Hon

oris

; the

muc

h-de

grad

ed m

ain

ring

of

the

Tra

nqui

llita

tis

Bas

in t

rave

rses

Jul

ius

Cae

sar.

Rim

ae M

acle

ar a

ndR

imae

Sos

igen

es a

re c

ircu

mfe

rent

ial f

ault

s at

the

edge

of M

are

Tra

nqui

llita

tis.

Men

elau

s ha

s im

pact

ed p

reci

sely

on

the

inne

r ri

m o

f th

e m

ain

ring

of

the

Sere

nita

tis

Bas

in, p

roje

ctin

g ra

ys in

all

dire

ctio

ns.

21

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

090H

2Su

n El

evat

ion:

21.

6°A

ltit

ude:

271

1.26

km

The

floo

ded

floor

of t

he S

eren

itat

is B

asin

sho

ws

only

sub

tle

vari

atio

n. D

orsu

mA

zara

may

rep

rese

nt a

flow

bou

ndar

y or

may

be

part

of

a pa

tter

n m

arki

ng a

subm

erge

d cr

ater

. T

he b

righ

t st

reak

s ra

diat

e no

t fr

om B

esse

l, bu

t fr

omM

enel

aus

to th

e so

uth

(LO

4-09

0H2)

.

21

5Se

renita

tis

Ba

sin R

egio

n

LO4-

090H

3Su

n El

evat

ion:

21.

6°A

ltit

ude:

271

1.26

km

In th

is n

orth

east

ern

part

of M

are

Sere

nita

tis,

an

incr

ease

d fr

eque

ncy

of r

idge

sin

dica

te a

tra

nsit

ion

from

the

dee

p la

va o

f M

are

Sere

nita

tis

to t

he s

hallo

wer

Lacu

s So

mni

orum

(LO

4-09

1H2)

, no

rthe

ast

of L

uthe

r. T

he b

righ

tnes

s of

the

mar

e su

rfac

e co

mes

fro

m r

ays

from

Cop

erni

can

crat

ers

Bur

g (t

o th

e no

rth)

and

Tha

les

(far

to th

e no

rthe

ast)

.

21

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

091H

1Su

n El

evat

ion:

23.

7°A

ltit

ude:

294

7.25

km

Lacu

s So

mni

orum

has

bee

n fo

rmed

by

the

flood

ing

of a

com

plex

dep

ress

ion

that

sho

ws

sign

s of

mul

tipl

e un

derl

ying

cra

ters

. A s

ingl

e la

rge

crat

er s

eem

s to

unde

rlie

Lac

us M

orti

s. B

urg

is a

Cop

erni

can

crat

er w

ith

a w

ell-

deve

lope

d ra

ypa

tter

n. T

he fl

oor

of L

acus

Mor

tis

show

s ex

tens

ive

frac

turi

ng,

incl

udin

g a

scar

p th

at is

abo

ut 8

00 m

in h

eigh

t, ju

dgin

g by

its

shad

ow a

t 23

.7°

sun

elev

a-ti

on. T

here

is s

ome

evid

ence

of

dark

dep

osit

s in

the

vic

init

y of

fau

lts

(rim

ae)

in L

acus

Mor

tis,

sug

gest

ing

the

rele

ase

of v

olat

iles

afte

r th

e de

posi

t of

ray

sfr

om th

e B

urg

impa

ct.

21

7Se

renita

tis

Ba

sin R

egio

n

LO4-

091H

2Su

n El

evat

ion:

23.

7°A

ltit

ude:

294

7.25

km

Thi

s ea

ster

n pa

rt o

f Mar

e Fr

igor

is is

old

er th

an th

e w

este

rn p

art,

acco

rdin

g to

crat

er c

ount

s. T

here

are

sig

ns o

f a p

ossi

ble

basi

n (3

60 k

m, 5

5°N

, 30°

E) u

nder

this

par

t of M

are

Frig

oris

. The

rid

ge r

unni

ng th

roug

h B

aily

and

aro

und

to ju

stso

uthe

ast

of G

artn

er,

coul

d be

the

rim

of

a ba

sin

unde

rlyi

ng w

este

rn M

are

Frig

oris

(LO

4-09

8H3)

. Thi

s ar

ea s

how

s a

num

ber

of m

are

ridg

es (

dors

a) t

hat

are

influ

ence

d by

the

unde

rlyi

ng to

pogr

aphy

. Bai

ly s

eem

s to

hav

e be

en fo

rmed

by a

pai

r of

impa

ctor

s ar

rivi

ng s

ide

by s

ide

into

a h

ighl

and

area

at a

low

ang

lefr

om t

he e

ast-

nort

heas

t. T

he c

ompo

und

crat

er w

as s

ubse

quen

tly

flood

ed b

yla

va a

nd th

en it

s flo

or w

as fr

actu

red,

form

ing

the

rim

ae in

the

crat

er fl

oor.

21

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

091H

3Su

n El

evat

ion:

23.

7°A

ltit

ude:

294

7.25

km

Mar

e T

ranq

uilli

tati

s w

as a

pri

me

choi

ce f

or t

he fi

rst

Apo

llo l

andi

ng s

ite

beca

use

of it

s la

rge

smoo

th a

rea

and

equa

tori

al p

osit

ion.

Fur

ther

, its

eas

tern

loca

tion

mad

e it

a fi

rst

choi

ce w

ithi

n a

laun

ch w

indo

w. R

ange

r 8

was

the

firs

tto

ret

urn

deta

iled

pict

ures

fro

m t

his

site

in

Febr

uary

196

5, c

onfir

min

g th

eto

pogr

aphi

c su

itab

ility

for

a m

anne

d la

ndin

g bu

t lea

ving

ope

n th

e qu

esti

on o

fso

il st

reng

th. S

urve

yor

5 (S

epte

mbe

r 19

67)

confi

rmed

the

firm

ness

of

luna

rso

il he

re. A

n al

pha-

scat

teri

ng e

xper

imen

t fo

und

that

the

che

mic

al c

ompo

si-

tion

of

the

mar

e so

il w

as c

hara

cter

isti

c of

bas

alt.

As

can

be s

een

from

thi

sLu

nar

Orb

iter

pho

to, t

he la

ndin

g si

te fo

r A

pollo

11

was

cho

sen

to b

e as

flat

and

feat

urel

ess

as p

ossi

ble,

nea

rly

free

of l

arge

cra

ters

and

rid

ges

that

cou

ld je

opar

-di

ze a

land

ing.

On

July

20,

196

9, E

agle

land

ed a

t Tra

nqui

lity

Bas

e. T

he m

issi

onre

turn

ed 2

2 kg

of s

ampl

es c

olle

cted

from

the

mar

e by

Arm

stro

ng a

nd A

ldri

n,in

clud

ing

rock

s 3.

6 bi

llion

yea

rs o

ld.

21

9Se

renita

tis

Ba

sin R

egio

n

LO4-

085H

1Su

n El

evat

ion:

22.

5°A

ltit

ude:

271

6.89

km

Nea

r Pl

iniu

s, t

he m

ain

ring

of

the

Sere

nita

tis

Bas

in i

nter

sect

s th

e m

ain

ring

of

the

pre

exis

ting

Tra

nqui

llita

tis

Bas

in. S

eren

itat

is d

oubt

less

dem

olis

hed

and

disp

erse

d th

e m

ain

ring

of

Tra

nqui

llita

tis.

The

mel

t sh

eet

of T

ranq

uilli

tati

sm

ay h

ave

supp

ress

ed t

he s

ecto

r of

the

mai

n ri

ng o

f Se

reni

tati

s be

yond

Prom

onto

rium

Arc

heru

sia.

An

exte

nsiv

e fr

actu

re z

one,

mar

ked

by R

imae

Plin

ius,

pas

ses

whe

re th

e m

ain

ring

of S

eren

itat

is w

ould

be

expe

cted

. The

last

laye

r of

lava

to fl

ow b

etw

een

the

two

basi

ns h

as c

ome

from

Tra

nqui

llita

tis;

its

boun

dary

can

be

seen

nor

thw

est o

f Pro

mon

tori

um A

rche

rusi

a. R

idge

s in

Mar

eT

ranq

uilli

tati

s sh

ow e

vide

nce

of t

he u

nder

lyin

g to

pogr

aphy

, ind

icat

ing

that

the

mar

e m

ay b

e sh

allo

w h

ere.

22

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

085H

2Su

n El

evat

ion:

22.

5°A

ltit

ude:

271

6.89

km

The

are

a to

the

righ

t of t

his

phot

o, to

war

d th

e ea

ster

n ed

ge o

f Mar

e Se

reni

tati

s,is

not

onl

y da

rker

but

of

a di

ffer

ent

spec

tral

cla

ss t

han

the

cent

ral

mar

esu

rfac

e. I

t m

ay b

e co

vere

d w

ith

dark

man

tlin

g m

ater

ial.

See

also

LO

4-07

8H3,

who

se v

iew

con

tinu

es to

the

east

.

22

1Se

renita

tis

Ba

sin R

egio

n

LO4-

085H

3Su

n El

evat

ion:

22.

5°A

ltit

ude:

271

6.89

km

The

cen

tral

and

sou

ther

n se

ctio

ns o

f D

orsa

Sm

irno

v m

aym

ark

an in

ner

ring

of t

he S

eren

itat

is B

asin

. The

ext

ensi

on o

fM

are

Sere

nita

tis

to t

he n

orth

may

rep

rese

nt a

flow

of

lava

nort

h fr

om M

are

Sere

nita

tis

thro

ugh

Lacu

s So

mni

orum

and

Lacu

s M

orti

s to

war

d M

are

Frig

oris

. Thi

s ph

oto

was

exp

osed

for

the

mar

e, n

ot f

or t

he b

righ

ter

high

land

s. T

here

is

bett

erco

vera

ge o

f Pos

idon

ius

in L

O4-

079H

1.

LO4-

086H

1Su

n El

evat

ion:

23.

7°A

ltit

ude:

295

6.08

km

22

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

22

3Se

renita

tis

Ba

sin R

egio

n

Cra

ters

Pla

na a

nd M

ason

hav

e im

pact

ed th

e m

ain

ring

of t

hela

rge

crat

er b

enea

th L

acus

Mor

tis

(see

LO

4-09

1H2)

, cau

sing

the

stra

nge

patt

ern

of r

edis

trib

uted

mat

eria

l su

rrou

ndin

gth

em. I

n pa

rtic

ular

, cra

ter

Mas

on h

as t

hrow

n he

avy

lobe

s of

debr

is t

o th

e so

uthe

ast,

mod

ifyi

ng e

ject

a fr

om t

he c

rate

rw

hose

rim

it h

as im

pact

ed.

LO4-

086H

2Su

n El

evat

ion:

23.

7°A

ltit

ude:

295

6.08

km

One objective of the Apollo 17 Mission(December 1972) in the Taurus-Littrowvalley was to sample the dark mantlingmaterial in this area. Although the ma-terial was mostly covered, it was ex-cavated and exposed by the impact oflocal craters. Sampled by Schmitt andCernan, it is composed of beads of a ti-tanium-rich composition that is darkorange if a glass and black if crystal-lized. Aged at 3.4 billion years old, it isgenerated by volcanic fountains drivenby an unknown volatile material.

Lava may have risen through a hard-ening surface at Dorsa Barlow, runningthrough Rima Jansen to the northwestand filling a crater about 50 km north of Jansen. The main rings of Tranquil-litatis and Serenitatis each pass betweenDawes and Fabbroni, but there are nomountains there. Perhaps Serenitatis de-stroyed this sector of the Tranquillitatisring and the melt sheet of Tranquillitatissuppressed the Serenitatis ring.

The highlands near Copernican craterCensorinus in the bottom right cornerof this photo mark the remains of thesouthwest sector of the much-degradedmain ring of the Tranquillitatis Basin(see Photos LO4-077H3 and LO4-072H3in the Nectaris Basin Region).

22

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Luna

21,

the

firs

t of

thr

ee p

ost-

Apo

llo u

nman

ned

succ

esse

sof

the

USS

R l

unar

pro

gram

, la

nded

in

Janu

ary

1973

. It

depl

oyed

the

sec

ond

Luno

khod

rov

er.

On

the

floor

of

LeM

onni

er, t

his

rove

r en

coun

tere

d sl

ippe

ry g

oing

(80

% w

heel

slip

) an

d sa

nk to

its

axle

s at

one

poi

nt in

side

a c

rate

r. T

his

isco

nsis

tent

wit

h Le

Mon

nier

bei

ng h

eavi

ly c

over

ed w

ith

un-

com

pact

ed d

ark

man

tlin

g m

ater

ial.

The

rov

er m

oved

fro

mth

e la

ndin

g si

te in

to th

e fo

othi

lls o

f Mon

tes

Tau

rus,

find

ing

ade

crea

se i

n ir

on c

onte

nt f

rom

9%

to

4%.

It a

lso

expl

ored

an

ope

n cr

ack

in t

he b

asal

t m

ore

than

300

m w

ide.

Upl

ift

from

ris

ing

lava

has

rai

sed

the

grea

ter

part

of

the

floor

of

Lat

e Im

bria

n Po

sido

nius

nea

rly

to t

he t

op o

f it

s ri

m

(LO

4-07

9H3)

.

LO4-

079H

1Su

n El

evat

ion:

24.

5°A

ltit

ude:

296

3.78

km

22

5Se

renita

tis

Ba

sin R

egio

n

Atl

as i

s be

lieve

d to

be

Late

Im

bria

n in

age

and

Her

cule

s to

be

Era

tost

heni

an (

the

nger

per

iod)

. It

is in

tere

stin

gto

com

pare

the

degr

ee o

f deg

rada

tion

and

inte

rpla

y of

eje

cta

betw

een

the

two

crat

ers

of c

ompa

rabl

e si

ze,

impa

ctin

gsi

mil

ar t

erra

in.

Mor

e of

the

se c

rate

rs c

an b

e se

en i

n LO

4-07

9H3.

Lac

us S

omni

orum

is q

uite

sha

llow

, as

indi

cate

dby

the

man

y pa

rtia

lly fl

oode

d cr

ater

s an

d is

land

s ab

ove

the

mar

e su

rfac

e.

LO4-

079H

2Su

n El

evat

ion:

24.

5°A

ltit

ude:

296

3.78

km

22

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Atl

as h

as a

n up

lift

ed fl

oor,

lik

e th

e flo

ors

of P

osid

oniu

s(L

O4-

079H

1) a

nd H

umbo

ldt,

othe

r La

te I

mbr

ian

crat

ers

init

s si

ze r

ange

. Per

haps

thi

s is

cha

ract

eris

tic

of l

arge

cra

ters

that

impa

cted

in th

is p

erio

d bu

t wer

e no

t floo

ded

wit

h m

are.

Smal

l lak

es o

f mar

e m

ater

ial i

n th

e up

per

righ

t of t

his

phot

oal

so a

ppea

r ne

ar o

ther

mar

ia.

LO4-

079H

3Su

n El

evat

ion:

24.

5°A

ltit

ude:

296

3.78

km

22

7Se

renita

tis

Ba

sin R

egio

n

Montes Taurus separates the Serenitatisand Crisium Basins; it is within a radiusfrom the rim of each, and no doubt re-ceived ejecta from both, overlaid withImbrium ejecta. An 85-km crater mayunderlie Sinus Amoris. Romer, Hill, and Carmichael are fresh Copernicancraters. Chains and clusters of Imbriumsecondary craters are east of Romer.

The IAU named Diana and Grace in1979. Were the IAU representativesthinking of two commoners who mar-ried royalty? Mons Esam is a moundsurmounted by a crater, in the middleof a mare. It looks like an ash cone orfumarole, a possible source of darkmantling material. Rima Cauchy (arille) and Rupes Cauchy (a scarp) prob-ably are both surface expressions offaults in the mare.

The Censorinus Highlands arelocated at a triple intersection of themain rings of the Tranquillitatis andFecunditatis Basins and the first outerring of the Nectaris Basin. Shaking may have leveled Imbrium ejecta in theterra plains unit between Censorinusand Leakey. There are deposits of darkmantling along the shoreline of MareTranquillitatis and on the Censorinushighlands.

22

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Ejec

ta w

ith

stri

atio

ns r

adia

l to

the

Cri

sium

Bas

in c

an b

e se

en in

the

low

er r

ight

corn

er o

f th

is p

hoto

, sou

th o

f N

ewco

mb.

New

com

b an

d R

omer

see

m f

ree

ofsu

ch e

ject

a, b

ut K

irch

off s

how

s pr

obab

le s

econ

dari

es fr

om C

risi

um. N

ewco

mb

is a

ver

y co

mpl

ex c

rate

r. E

xten

sive

slu

mpi

ng h

as le

ft d

eep

scal

lops

on

its

rim

.T

he im

pact

of

the

20-k

m c

rate

r ju

st s

outh

wes

t of

New

com

b m

ay h

ave

caus

edth

e ex

tens

ive

colla

pse

of th

e ne

arby

wal

l.

22

9Se

renita

tis

Ba

sin R

egio

n

LO4-

074H

1Su

n El

evat

ion:

25.

2°A

ltit

ude:

296

9.81

km

The

str

uctu

re n

orth

of

Mau

ry i

s ve

ry u

nusu

al. I

t lo

oks

like

a sh

ield

vol

cano

that

has

eru

pted

in

abou

t fo

ur e

piso

des,

eac

h w

ith

lava

tha

t is

muc

h m

ore

visc

ous

than

oth

er fl

ows

on th

e M

oon.

Mor

e lik

ely,

how

ever

, it i

s m

olte

n ej

ecta

or a

sal

vo o

f la

va b

ombs

fro

m C

risi

um t

o th

e so

uth.

Pri

mar

y cr

ater

s in

thi

s

23

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

074H

2Su

n El

evat

ion:

25.

2°A

ltit

ude:

296

9.81

km

area

are

ass

igne

d to

div

erse

age

ran

ges.

Fra

nklin

is o

f the

Ear

ly Im

bria

n Ep

och,

Atl

as i

s of

the

Lat

e Im

bria

n Ep

och,

Her

cule

s is

of

the

Erat

osth

enia

n Pe

riod

,an

d C

ephe

us is

Cop

erni

can.

This part of Montes Taurus is a high-lands area between the Serenitatis, Tran-quillitatis, and Crisium Basins. Theridges near Lacus Bonitatis are radial tothe Crisium Basin, whose main ring runs through Macrobius. Lacus Bonitatis,running at right angles to the ridges, is inan outer trough of Crisium.

The complex region east of MareTranquillitatis has been influenced bymany basins. Sinus Concordiae hasflooded part of an outer trough of theFecunditatis Basin, beyond the ring thatpasses north of da Vinci. Palus Somni hasreceived deposits from Tranquillitatis,Fecunditatis, Crisium, Serenitatis, andImbrium (in that order). These depositscover the eastern sector of the main ringof Tranquillitatis as it passes east of Lyell.The highland peaks between Cauchy andda Vinci are at an intersection of ringsfrom the Tranquillitatis and FecunditatisBasins.

An outer ring of the FecunditatisBasin passes near Zahringer, and themain ring of Tranquillitatis passes byMontes Secchi. The intersection ofthese two rings, just north of Lawrence,has raised a plateau (LO4-066H3). TheCensorinus highlands are in the bottomleft. Dark mantling material has slid offsteep slopes of these mountains, leavingbright areas.

23

1Se

renita

tis

Ba

sin R

egio

n

The

lar

ge t

roug

h be

twee

n N

ewco

mb

and

Deb

es m

ay h

ave

been

ini

tial

ly f

orm

ed b

y a

chai

n of

cra

ters

fro

m t

he T

ran-

quil

lita

tis

impa

ct a

nd t

hen

been

rei

nfor

ced

as a

n ou

ter

trou

gh o

f th

e C

risi

um B

asin

. Sh

akin

g fr

om t

he C

risi

umim

pact

may

hav

e se

rved

to le

vel d

epos

its

in th

e ar

ea fr

om th

eFe

cund

itat

is B

asin

as

wel

l.

LO4-

067H

1Su

n El

evat

ion:

24.

7°A

ltit

ude:

297

5.55

km

23

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

are

a be

twee

n Fr

ankl

in a

nd L

acus

Tem

pori

s is

too

flat

to

be

crat

er-s

atur

ated

hig

hlan

ds,

yet

it i

s no

t co

mpl

etel

yflo

oded

wit

h m

are

mat

eria

l ev

en t

houg

h cr

ater

s su

ch a

sC

heva

llier

, Shu

ckbu

rgh,

and

Oer

sted

hav

e be

en p

artl

y su

b-m

erge

d. C

lem

enti

ne e

leva

tion

dat

a sh

ows

a ro

ughl

y ci

r-cu

lar

depr

essi

on c

ente

red

at 5

3.5°

E an

d 42

.0°

N (

near

Shuc

kbur

gh),

abo

ut 4

00 k

m i

n di

amet

er (

incl

udin

g bo

thFr

ankl

in a

nd L

acus

Tem

pori

s). T

his

depr

essi

on m

ay m

ark

aba

sin

that

has

leve

led

this

reg

ion.

LO4-

067H

2Su

n El

evat

ion:

24.

7°A

ltit

ude:

297

5.55

km

23

3Se

renita

tis

Ba

sin R

egio

n

The

Nec

tari

an c

rate

r En

dym

ion

has

been

sca

rred

by

ejec

tafr

om t

he H

umbo

ldti

anum

Bas

in, o

f th

e sa

me

peri

od. E

ndy-

mio

n is

loc

ated

in

an o

uter

tro

ugh

of t

he H

umbo

ldti

anum

Basi

n; th

e m

ain

ring

of t

he H

umbo

ldtia

num

Bas

in c

an b

e se

encr

ossi

ng th

e up

per

righ

t cor

ner

of th

is p

hoto

. The

sho

ck o

f the

Hum

bold

tian

um i

mpa

ct m

ay h

ave

been

the

cau

se o

f th

eun

usua

lly s

tron

g sl

umpi

ng o

f the

wal

l of E

ndym

ion.

LO4-

067H

3Su

n El

evat

ion:

24.

7°A

ltit

ude:

297

5.55

km

23

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Failu

re o

f Lu

nar

Orb

iter

’s t

herm

al d

oor

(len

s ca

p) c

ause

dgl

are

that

str

ongl

y af

fect

ed t

his

phot

o. T

his

area

inc

lude

s th

e no

rthw

este

rn p

orti

on o

f th

e flo

or o

f M

are

Fecu

ndit

atis

(the

sou

ther

n po

rtio

n is

in

the

Nec

tari

s B

asin

Reg

ion)

. The

brig

hter

are

a in

the

upp

er r

ight

-han

d co

rner

is

a hi

ghla

ndar

ea c

lose

to

Mar

e C

risi

um (

LO4-

061H

2).

The

Cop

erni

can

crat

er T

arun

tius

im

pact

ed a

fter

the

mar

e flo

odin

g. R

isin

gla

va h

as u

plif

ted

a m

elt

shee

t on

its

floor

; the

res

ulti

ng f

rac-

ture

s un

derl

ie R

imae

Tar

unti

us.

Cat

ena

Tar

unti

us l

ies

betw

een

Tar

unti

us a

nd A

nvill

e bu

t ca

nnot

be

seen

in

this

phot

o.

LO4-

061H

1Su

n El

evat

ion:

24.

6°A

ltit

ude:

273

4.00

km

23

5Se

renita

tis

Ba

sin R

egio

n

Thi

s vi

ew o

f th

e w

este

rn s

hore

of

Mar

e C

risi

um s

how

sst

riat

ions

of t

he li

mit

ed e

ject

a pa

tter

n in

this

dir

ecti

on. O

ther

coar

ser

stri

atio

ns

(and

re

mot

e se

nsin

g da

ta

from

Cle

men

tine

) in

dica

te th

at th

is C

risi

um e

ject

a ha

s be

en s

ubse

-qu

entl

y co

vere

d w

ith

ejec

ta f

rom

the

Im

briu

m a

nd/o

rSe

reni

tati

s B

asin

to

the

nort

hwes

t (b

oth

in t

he s

ame

dire

c-ti

on a

nd b

oth

rim

s be

ing

two

basi

n ra

dii a

way

). T

he s

moo

thsl

opin

g w

alls

of

Proc

lus

indi

cate

tha

t it

has

im

pact

ed r

ela-

tive

ly u

nlay

ered

, un

com

pact

ed m

ater

ial.

Such

is

typi

cal

ofth

e ej

ecta

bla

nket

jus

t ou

tsid

e a

basi

n ri

m, i

n th

is c

ase

the

Cri

sium

Bas

in. P

rocl

us i

s a

youn

g C

oper

nica

n cr

ater

wit

h a

spec

tacu

lar

ray

patt

ern.

Par

t of

the

pat

tern

can

be

seen

on

the

floor

of M

are

Cri

sium

.

LO4-

061H

2Su

n El

evat

ion:

24.

6°A

ltit

ude:

273

4.00

km

23

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s ar

ea t

o th

e no

rthw

est

of M

are

Cri

sium

pro

babl

y sh

ows

ejec

ta f

rom

the

Tra

nqui

llita

tis

Bas

in t

o th

e so

uthw

est,

only

abou

t on

e ba

sin

radi

us fr

om t

he m

ain

ring

, as

wel

l as

ridg

esan

d va

lleys

fr

om

the

dire

ctio

n of

th

e Im

briu

m

and

Sere

nita

tis

Bas

ins.

The

out

er t

roug

h of

the

Cri

sium

Bas

in i

sflo

oded

wit

h m

are,

whi

ch c

onti

nues

int

o th

e flo

or o

fC

leom

edes

. The

bro

ad e

long

ated

dep

ress

ion

in th

e up

per

left

corn

er i

s ra

dial

to

Tra

nqui

llita

tis

(LO

4-06

7H1)

. A

val

ley

half

way

bet

wee

n T

isse

rand

and

Cle

omed

es i

s ra

dial

to

Cri

sium

.

LO4-

061H

3Su

n El

evat

ion:

24.

6°A

ltit

ude:

273

4.00

km

23

7Se

renita

tis

Ba

sin R

egio

n

Thi

s ar

ea i

s ab

out

two

basi

n ra

dii

away

fro

m t

he I

mbr

ium

,Se

reni

tati

s, T

ranq

uilli

tati

s, a

nd H

umbo

ldti

anum

Bas

ins

and

is a

bout

one

bas

in r

adiu

s aw

ay fr

om t

he C

risi

um B

asin

. It

islik

ely

that

rug

ged

high

land

s ar

e co

vere

d w

ith

a th

ick

blan

ket

of p

ulve

rize

d ej

ecta

that

has

som

ewha

t lev

eled

the

terr

ain.

Ave

ry s

moo

th a

rea

in a

dep

ress

ion

that

may

hav

e be

en fo

rmed

by a

cha

in o

f cr

ater

s fr

om t

he C

risi

um B

asin

lie

s be

twee

nG

emin

us a

nd B

erze

lius.

Per

haps

it

is e

ject

a th

at h

as b

een

furt

her

leve

led

by l

ocal

tec

toni

c fo

rces

. G

emin

us h

as a

com

plex

, ter

race

d w

all,

sugg

esti

ng t

hat

it i

mpa

cted

lay

ered

mat

eria

l. C

leom

edes

, som

ewha

t de

grad

ed, b

ut w

ith

its

own

ejec

ta p

atte

rn in

tact

, is

thou

ght t

o be

Nec

tari

an.

LO4-

062H

1Su

n El

evat

ion:

25.

4°A

ltit

ude:

297

9.32

km

23

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

wes

tern

par

ts o

f M

essa

la h

ave

rece

ived

hea

vy d

epos

its

from

Cri

sium

to

the

sout

h. A

ddit

iona

l bu

t fin

er d

epos

its

from

C

risi

um

can

be

seen

be

twee

n C

arri

ngto

n an

dSc

hum

ache

r. L

acus

Tem

port

is, S

huck

burg

h, a

nd H

ooke

may

be l

ocat

ed i

n th

e flo

or o

f an

anc

ient

cra

ter

or b

asin

(se

e LO

4-06

7H2)

. M

essa

la a

nd t

he 3

0-km

cra

ter

in i

ts w

este

rnflo

or a

re b

oth

iden

tifie

d as

of t

he P

re-N

ecta

rian

Per

iod.

LO4-

062H

2Su

n El

evat

ion:

25.

4°A

ltit

ude:

297

9.32

km

23

9Se

renita

tis

Ba

sin R

egio

n

The ring that bounds Mare Crisium hasa flat-topped structure like a plateau. In comparison with Orientale rings, this ring is more like one of the MontesRook rings (inner rings) than likeMontes Cordillera (the main ring).There is sporadic lava flooding beyondthis inner ring, just as in the OrientaleBasin.

The Crisium Basin has its ownmascon, revealing an internal source of lava from beneath the crust. An“isthmus” of about 200 km separatesMare Crisium and Mare Fecunditatis.This narrow strip of highlands is deeplyscored by ejecta from the youngerCrisium.

Luna 16 (September 1970) landed onMare Fecunditatis, drilled a 35-cm core,and returned a 101-gram (101-g) sam-ple to earth. It showed a mineral com-position similar to that of other mariasamples, with some quantitative differ-ences. Luna 18 (September 1971) failedupon landing, possibly due to the rough-ness of its landing site. Luna 20 (February1972) returned 50 g of samples, probablyCrisium ejecta. The samples are distinctlydifferent from mare material; lighter incolor and higher in density, the samplesare similar to those gathered by Apollofrom other basin rims.

24

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

lar

ge fl

at a

rea

east

of

Bur

ckha

rdt

is i

n an

out

er t

roug

h of

the

Cri

sium

Bas

in. I

n C

lem

enti

ne a

lbed

o da

ta, i

t has

a d

ark,

mot

tled

look

as

if it

is in

com

-pl

etel

y flo

oded

wit

h m

are

mat

eria

l. T

he fl

atte

ning

may

hav

e be

en p

artly

cau

sed

by t

he f

orm

atio

n of

the

tro

ugh

of C

risi

um, p

artl

y by

tec

toni

c sh

akin

g of

un-

cons

olid

ated

hig

hlan

ds, a

nd p

artly

by

mar

e flo

odin

g.

24

1Se

renita

tis

Ba

sin R

egio

n

LO4-

055H

1Su

n El

evat

ion:

25.

8°A

ltit

ude:

298

2.10

km

LO4-

055H

2Su

n El

evat

ion:

25.

8°A

ltit

ude:

298

2.10

km

24

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Cha

ins

of s

econ

dary

cra

ters

in

this

are

a ra

diat

e fr

om t

he H

umbo

ldti

anum

Bas

in t

o th

e no

rthe

ast.

In C

lem

enti

ne a

lbed

o da

ta, L

acus

Spe

i is

a d

ark

and

wel

l-de

fined

are

a of

mar

e flo

odin

g. S

chum

ache

r is

als

o flo

oded

wit

h m

are

mat

eria

l. Fo

r a

clea

rer

phot

ogra

ph o

f th

is a

rea

see

LO4-

165H

2 in

the

Eas

tern

Bas

ins

Reg

ion,

Cha

pter

10.

Ray

s fr

om H

ayn

to th

e no

rthe

ast a

ppea

r ve

rtic

al in

this

pic

ture

bec

ause

of i

tsor

ient

atio

n. T

he m

ain

ring

of

the

Hum

bold

tian

um B

asin

pas

ses

acro

ss t

helo

wer

left

cor

ner

of t

his

phot

o; a

n in

ner

ring

bou

nds

Mar

e H

umbo

ldti

anum

.B

etw

een

the

two

ring

s is

an

area

tha

t ha

s be

en fl

atte

ned

by t

he f

orce

s th

atcr

eate

d th

e tr

ough

.

24

3Se

renita

tis

Ba

sin R

egio

n

LO4-

055H

3Su

n El

evat

ion:

25.

8°A

ltit

ude:

298

2.10

km

10.1. OverviewThe Eastern Basins Region covers roughly the area between60° east longitude and the eastern limb (90° east longitude)and between 60° south latitude and 60° north latitude.

The region contains part of several definite ringed basins,Crisium, Australe, Smythii, and Humboldtianum (southernpart) in downward order of size, and the probable basin,Balmer-Kapteyn. Each of these basins has some mare mater-ial within it, but (with the exception of Mare Crisium) themare is irregular, probably because this region is midwaybetween the thin crust of the western and central near sideand the thick crust of the far side.

Although the basins in this region are older than Imbrium,they are relatively free of its influence becausee the region ismostly beyond a basin radius away from the main ring ofImbrium.

The Crisium BasinThe Crisium Basin has a topographic rim 740 km in diame-ter. It is one of the younger basins and is particularly inter-esting. It represents the transition between the older basinsto the west, strongly dominated by ejecta from the giant,relatively young Imbrium Basin, and basins near the easternlimb and on the far side that are relatively free of theinfluence of Imbrium.

In a first impression, the Crisium Basin appears to be elon-gated in form, which might be taken as evidence of a glanc-ing impact. On closer inspection, the shape resolves into twocircular basins, as shown in Figure 10.1.

The western, northern, and southern shores of the CrisiumBasin are nearly covered with ridges and valleys formed byejecta from the Imbrium Basin to the northwest. To the east,the topography is dominated by ejecta from Crisium itself.Clementine multispectral data show a strong differencebetween the mineral signatures to the west, which is uppercrust ejected from the Imbrium Basin, and the signatures tothe east, which are believed to contain portions of lowercrust below the Crisium Basin.

The Australe BasinThe Australe Basin is partly on the near side and partly onthe far side; its center is at 52° south latitude and 95° eastlongitude. Since it was formed in the Pre-Nectarian Period, ithas been severely degraded. No rings outside of the main

ring have been identified, but at least one inner ring has beentraced.

The central part of this basin has been only partiallyflooded with mare lava. As seen in Figure 10.2, lava haserupted only where impactors have formed large craters inthe basin floor. Perhaps the central Australe Basin had an ex-tensive melt sheet that inhibited the rise of lava except whereit has been penetrated.

The Smythii BasinThe Smythii Basin, as large as Crisium, is at 2° south latitudeand 87° east longitude and straddles the eastern limb. It isbest seen in Lunar Orbiter 2 photograph 196M, shown inFigure 10.3. There is a mascon associated with Mare Smythii.

10.2. High-Resolution ImagesLunar Orbiter 4 was planned to start its photographicmission at the eastern limb with a series of photos like the

Chapter 10

Eastern Basins Region

Figure 10.1. Crisium Basin (part of LO4-060M). Mare Crisium lookssomewhat like a flounder. Mare Fecunditatis and Mare Tranquillitatis are inthe lower left corner of the figure. Mare Marginis is far to the right. MareUndarum, the dark area southeast of Crisium, is in an intersection of outertroughs of the Crisium and Fecunditatis Basins. Mare Crisium has floodeddepressions from a complex series of impacts. The circular shape of thelargest depression has been modified by a large crater or basin to the west-northwest of the main impact and a smaller crater to the east (the “tail of thefish”).

24

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

rest of the mission, systematically taking four to six expo-sures on each orbit from near perilune, at an altitude ofabout 3000 km.

Unfortunately, the thermal door (a lens cap) locked open,leaving the optics open to the cold of space. As a resultmoisture condensed on the inside of the lenses (much as dewmight settle on the outside of a lens), fogging the pho-tographs. After analysis, the spacecraft was kept pointing atthe lunar surface (warmer than deep space) and the lenscleared. Meanwhile, many exposures were lost or badly de-graded. Of the planned high-resolution photos in this region,only LO4-009H and LO4-018H are printed in this chapter.

The mission operators compensated for the loss by schedul-ing a series of photos near the end of the mission, when theapolune (the other end of the orbit, at about 5500 km) cameover the eastern limb. These are the photos used to cover theEastern Basins Region. The resolution is of course lower andthe coverage larger. As a result, two subframes from each ofthese exposures cover parts of this region. The remaining sub-frames cover parts of the North and South Polar Regions. Table10.1 shows the high-resolution images of the Eastern BasinsRegion in schematic form.

The following pages show the high-resolution subframesfrom south to north and west to east. The apolune photos arein the order LO4-191H3, LO4-191H2, LO4-184H2, LO4-184H1, LO4-178H2, LO4-178H1, LO4-177H3, LO4-177H2,

LO4-165H3, and LO4-165H2. This seems like a confusing se-quence but it results from the spacecraft flying from north tosouth, in reverse of the usual direction. For consistency, wefollow the usual south to north convention, despite having topresent the pictures in the reverse order of their numbers.The perilune photos are presented in the order of LO4-018H1… LO4-018H3, LO4-009H1 … LO4-009H3 (the usual order).

Because of the loss of photography early in Lunar OrbiterMission 4, high-resolution exposures in the southern part ofthe Eastern Basins Region (with the exception of LO4-009)have been lost. To identify the features of this region, amedium-resolution photo from Mission 2 (LO2-196M) isprovided at the end of this chapter.

Figure 10.2. Australe Basin (LO4-009M). The center of the basin is slightlyleft and below the center of the photo. The main ring, most pronounced in theeastern sector, spans 30° of the lunar circumference. The dark circular featurenear the top is Mare Smythii, with radial ridges and valleys of the SmythiiBasin ejecta surrounding it. The Balmer-Kapteyn Basin straddles the termina-tor southwest of Mare Smythii. Near the bottom of the picture is Schrodinger,a small far side basin that nonetheless has strong radial valleys extending fromits main ring. The dark far side feature to the right is the flooded craterTsiolkovskiy. Half of the ancient South Pole–Aiken Basin of the far side is inthis picture. Its main ring intersects that of Australe. Schrodinger, but notTsiolkovskiy, is within the South Pole–Aiken Basin.

Figure 10.3. The Smythii Basin (LO2-196M). The dark compact mare tothe upper left is Mare Smythii, with Mare Marginis above it and a small areaof mare below it. The southeastern sector of the main topographic ring ofthe Smythii Basin can be seen curving from the top center and out the lowerleft side of this photo.

56 N–90 N 191H1 177H1 165H1 191H1

27 N–56 N 062 191H2 177H2 165H2

0–27 N 061 191H3 177H3 165H3 018

0–27 S 060 184H1178H1

27 S–56 S 059 184H2178H2 009

56 S–90 S 184H3178H3

Longitude 57 E 54 E 70 E 75 E 81 E 90 E 96 Eat Equator

Table 10.1. The cells shown in white represent the high-resolutionphotos of the Eastern Basins Region (LO4-XXX H1, -H2, and -H3, whereXXX is the Photo Number). The North Polar Region is to the north, theSerenitatis Basin Region is to the northwest, the Nectaris Basin Region is tothe southwest, and the South Polar Region is to the south. The far side is tothe east. Exposures 165 to 191 were taken from apolune in afternoon sun,and exposures 009 and 018 were taken at perilune in morning sun. Apolunephotos were taken at about twice the altitude of perilune photos, so theyhave about half the resolution and four times the area of coverage.

24

5Ea

ster

nBa

sins

Reg

ion

Mar

e A

ngui

s ha

s flo

oded

an

oute

r tr

ough

of

the

Cri

sium

Basi

n. T

he e

dge

of M

are

Fecu

ndit

atis

can

be

seen

in th

e lo

wer

left

cor

ner

of th

is p

hoto

. Dor

sum

Opp

el, t

oget

her

wit

h D

orsa

Tet

yaev

(LO

4-17

7H3)

, may

out

line

an in

ner

ring

, alo

ng w

ith

Dor

sum

Ter

mie

r an

d D

orsa

Har

ker

(not

vis

ible

her

e). D

ays

befo

re A

pollo

11

land

ed (

July

196

9), t

he r

etro

-roc

ket o

f Lun

a15

faile

d an

d it

cra

shed

. Lun

a 24

suc

cess

fully

land

ed (

Aug

ust

1976

) an

d re

turn

ed a

cor

e sa

mpl

e fr

om a

mar

e un

visi

ted

byA

pollo

. T

his

was

the

las

t sa

mpl

e re

turn

ed t

o Ea

rth

to t

his

day.

LO4-

191H

3Su

n El

evat

ion:

16.

3°A

ltit

ude:

550

3.39

km

24

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

eas

tern

par

t of t

his

area

is in

the

East

ern

Bas

ins

Reg

ion,

but

the

wes

tern

par

t is

in

the

Sere

nita

tis

Bas

in R

egio

n.B

ecau

se o

f th

e ov

erla

p, t

here

is

an o

ppor

tuni

ty t

o co

mpa

reth

e af

tern

oon

sun

illum

inat

ion

of t

his

phot

o (c

omin

g fr

omth

e ea

st)

wit

h th

e m

orni

ng s

un o

f th

e ph

otos

in

the

Sere

nita

tis

chap

ter

(Cha

pter

9).

Str

iati

ons

from

the

sout

h ar

era

dial

to

Cri

sium

and

tho

se f

rom

the

nor

thea

st a

re f

rom

Hum

bold

tian

um.

LO4-

191H

2Su

n El

evat

ion:

16.

3°A

ltit

ude:

550

3.39

km

24

7Ea

ster

nBa

sins

Reg

ion

Thi

s hi

ghla

nd a

rea

sout

heas

t of t

he F

ecun

dita

tis

Bas

in h

as e

xten

sive

cha

ins

ofse

cond

ary

crat

ers,

som

e ra

dial

to P

etav

ius

and

som

e fr

om th

e N

ecta

ris

Bas

in.

Rim

ae H

ase

are

stre

ss fr

actu

res

radi

al to

the

Nec

tari

s B

asin

. The

mai

n ri

ng o

fth

e m

uch-

degr

aded

Aus

tral

e B

asin

pas

ses

thro

ugh

Mar

inus

. T

he fl

at a

rea

LO4-

184H

2Su

n El

evat

ion:

6.9

°A

ltit

ude:

579

0.16

km

betw

een

thes

e cr

ater

s an

d Fu

rner

ius

(Lat

e Im

bria

n) m

ay b

e in

an

oute

r tr

ough

of t

his

larg

e, d

egra

ded,

Pre

-Nec

tari

an B

asin

. See

LO

4-05

3H1

and

LO4-

052H

3in

the

Nec

tari

s ch

apte

r (C

hapt

er 8

)for

a d

iscu

ssio

n of

the

fra

ctur

ed-fl

oor

crat

ers

Peta

vius

and

Fur

neri

us.

24

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s so

mew

hat

obliq

ue p

hoto

sho

ws

an o

verv

iew

of

the

equa

tori

al r

egio

n in

the

vici

nity

of

70°

east

lon

gitu

de.

The

Pre

-Nec

tari

an B

alm

er-K

apte

yn B

asin

can

clea

rly

be s

een.

Bal

mer

has

impa

cted

the

mai

n ri

ng o

f thi

s ba

sin.

Str

iati

ons

cros

sing

thi

s ba

sin

coul

d be

fro

m L

angr

enus

or

the

Fecu

ndit

atis

Bas

in. N

ote

the

larg

e di

ffer

ence

in

albe

do b

etw

een

Pre-

Nec

tari

an V

ende

linu

s an

d th

e

LO4-

184H

1Su

n El

evat

ion:

6.9

°A

ltit

ude:

579

0.16

km

Erat

osth

enia

n cr

ater

Lan

gren

us, w

hose

terr

aced

wal

l is

rela

tive

ly s

harp

. Lam

eha

s pu

shed

mat

eria

l fro

m t

he w

all o

f V

ende

linus

ont

o it

s flo

or. T

he c

hain

of

larg

e cr

ater

s be

twee

n K

apte

yn a

nd M

acLa

urin

and

the

sm

alle

r ch

ain

cros

sing

Lam

e ra

diat

e fr

om M

are

Cri

sium

. Se

e LO

4-05

4H1

(the

Ser

enit

atis

cha

pter

,C

hapt

er 9

) fo

r Lu

na 1

6, 1

8, a

nd 2

0.

24

9Ea

ster

nBa

sins

Reg

ion

Hum

bold

t is

a c

rate

r w

ith

an e

xten

sive

dep

osit

tha

t ex

tend

s in

to t

he A

ustr

ale

Bas

in,

who

se m

ain

ring

pas

ses

near

Oke

n an

d H

arla

n. H

umbo

ldt

has

a flo

or w

ith

a fr

actu

re p

atte

rn t

hat

reve

als

sign

s of

upl

ift

(see

the

ins

et f

rom

LO4-

027H

1, a

per

ilune

pho

to w

ith

mor

ning

ligh

t). D

ark

man

tling

mat

eria

l can

be s

een

on th

e flo

or o

f thi

s cr

ater

, nea

r th

e w

all.

Stri

atio

ns in

this

pho

to r

adia

tefr

om th

e N

ecta

ris

Bas

in.

LO4-

178H

2Su

n El

evat

ion:

1.5

°A

ltit

ude:

579

6.24

km

25

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s sh

ows

the

wes

tern

sec

tor

of t

he m

ain

ring

of

the

Smyt

hii

Bas

in, a

long

wit

h an

out

er tr

ough

(un

derl

ying

Kas

tner

) an

d ou

ter

ring

. Mar

e U

ndar

um fi

llsan

out

er t

roug

h of

the

Cri

sium

Bas

in,

to t

he n

orth

wes

t of

thi

s ph

oto.

Hec

atae

us a

nd t

he s

mal

ler

crat

er t

o it

s no

rth

show

sig

ns o

f a

sim

ulta

neou

sim

pact

. Spe

cific

ally

, the

eas

tern

rim

s of

the

tw

o cr

ater

s in

terl

ock;

nei

ther

can

be s

aid

to b

e su

peri

mpo

sed

on th

e ot

her.

LO4-

178H

1Su

n El

evat

ion:

1.5

°A

ltit

ude:

579

6.24

km

25

1Ea

ster

nBa

sins

Reg

ion

LO4-

177H

3 w

as t

aken

nea

r th

e en

d of

the

mis

sion

(su

n fr

om t

he w

est)

to

repl

ace

cove

rage

los

t at

the

beg

inni

ng b

ut g

lare

has

des

troy

ed m

ost

of t

heph

oto.

The

los

t ar

ea h

as b

een

repl

aced

her

e w

ith

part

of

med

ium

-res

olut

ion

phot

o LO

4-06

0M (

sun

from

the

east

). D

orsa

Tet

yaev

is p

art o

f a c

ircl

e of

mar

eri

dges

tha

t m

ay o

verl

ie a

n in

tern

al r

ing

of t

he C

risi

um B

asin

. The

rid

ges

and

LO4-

177H

3 an

d LO

4-06

0MSu

n El

evat

ion:

14.

8°A

ltit

ude:

549

1.85

km

valle

ys n

ear

Wild

t ar

e C

risi

um e

ject

a, p

roba

bly

over

lyin

g de

posi

ts f

rom

the

Smyt

hii

Bas

in. T

his

is t

he o

nly

area

whe

re C

risi

um e

ject

a is

exp

osed

: eje

cta

from

Im

briu

m a

nd S

eren

itat

is o

verl

ies

Cri

sium

eje

cta

to t

he w

est.

Mar

eU

ndar

um li

es in

an

oute

r tr

ough

of t

he C

risi

um B

asin

.

25

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Not

e th

e da

rk a

reas

thro

ugho

ut th

is r

egio

n, w

hich

may

indi

cate

dar

k m

antli

ngm

ater

ial.

The

str

ong

ridg

es a

nd v

alle

ys in

the

cen

ter

of t

his

phot

o ar

e pa

rt o

fth

e ej

ecta

bla

nket

from

the

Hum

bold

tian

um B

asin

dir

ectl

y to

the

nort

h, in

the

Nor

th P

olar

Reg

ion.

Hum

bold

tian

um is

cla

ssifi

ed a

s N

ecta

rian

, lik

e C

risi

um,

LO4-

177H

2Su

n El

evat

ion:

14.

8°A

ltit

ude:

549

1.85

km

but

is b

elie

ved

to b

e ol

der.

Zen

o, G

auss

, an

d ej

ecta

fro

m G

auss

are

sup

er-

impo

sed

on t

he H

umbo

ldti

anum

eje

cta

and

thus

mus

t be

you

nger

, but

the

yar

e st

ill c

lass

ified

as

Nec

tari

an fe

atur

es. N

ote

the

diff

eren

ce in

text

ure

sout

h of

Ber

osus

, as

Hum

bold

tian

um e

ject

a is

cov

ered

wit

h th

at o

f Cri

sium

.

25

3Ea

ster

nBa

sins

Reg

ion

(Jea

n-)

Fred

eric

Jol

iot

mar

ried

Ire

ne C

urie

, the

dau

ghte

r of

Pier

re a

nd M

arie

Cur

ie (

LO4-

165H

3).

Iren

e an

d Fr

eder

icJo

liot-

Cur

ie w

orke

d to

geth

er a

nd s

hare

d th

e N

obel

Pri

ze f

orsy

nthe

sizi

ng n

ew r

adio

acti

ve e

lem

ents

by

bom

bard

ing

targ

ets

wit

h al

pha

part

icle

s.

Mar

e M

argi

nis

is

not

deep

, an

dC

lem

enti

ne e

leva

tion

dat

a sh

ow a

pat

tern

tha

t is

mor

e lik

e a

colle

ctio

n of

cra

ters

suc

h as

Nep

er t

han

a ba

sin

floor

. The

pitt

ed a

rea

sout

h of

Can

non

and

Hub

ble

is a

t the

ant

ipod

es o

fth

e O

rien

tale

Bas

in (

see

also

LO

4-18

H2

and

-H3)

. As

in o

ther

such

cas

es, r

ocks

eje

cted

in a

ll di

rect

ions

from

Ori

enta

le h

ave

conv

erge

d he

re a

fter

tra

velin

g ha

lfw

ay a

roun

d th

e M

oon,

lead

ing

to a

loca

l hig

h de

nsit

y of

sm

all s

econ

dari

es.

LO4-

165H

3Su

n El

evat

ion:

13.

9°A

ltit

ude:

548

6.51

km

25

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s re

gion

is

dom

inat

ed b

y ri

dges

, va

lleys

and

sec

onda

rycr

ater

s of

the

Hum

bold

tian

um B

asin

to

the

nort

h, i

n th

eN

orth

Pol

ar R

egio

n. Z

eno

and

Gau

ss h

ave

been

sup

er-

impo

sed

on t

he H

umbo

ldti

anum

eje

cta.

Sec

onda

ries

fro

mC

risi

um t

o th

e so

uth

have

lan

ded

near

Zen

o. G

auss

is

unus

ual,

for

its

size

, in

havi

ng a

min

imal

cen

tral

pea

k.

LO4-

165H

2Su

n El

evat

ion:

13.

9°A

ltit

ude:

548

6.51

km

25

5Ea

ster

nBa

sins

Reg

ion

Mar

e Sm

ythi

i is

in a

wel

l-fo

rmed

Pre

-Nec

tari

an b

asin

. Cle

men

tine

dat

a sh

ow a

circ

ular

dep

ress

ion

(cen

tere

d ne

ar th

e m

iddl

e bo

ttom

edg

e of

this

pho

to)

wit

hth

e flo

or fl

oode

d by

mar

e m

ater

ial.

A m

asco

n in

dica

tes

a pl

ume

of la

va r

ose

from

the

man

tle.

Nec

tari

an c

rate

r N

eper

, whi

ch im

pact

ed th

e m

ain

ring

of t

heSm

ythi

i Bas

in, m

ay h

ave

been

floo

ded

thro

ugh

subs

urfa

ce la

va fl

ows

unde

r th

e

LO4-

018H

1Su

n El

evat

ion:

28.

4°A

ltit

ude:

273

9.66

km

chan

nel w

est

of T

acch

ini.

Sim

ilar

stru

ctur

es t

o th

e pl

atea

us a

nd v

alle

ys s

outh

of J

ansk

y ar

e se

en i

n th

e no

rthe

rn p

art

of t

he r

im o

f th

e O

rien

tale

Bas

in(M

onte

s C

ordi

llera

). O

ther

sim

ilari

ties

to

Ori

enta

le m

ay r

eflec

t th

e de

eper

crus

t und

er th

ese

basi

ns. T

acch

ini a

nd Ja

nsky

hav

e ex

tens

ive

depo

sits

of e

ject

afr

om th

e Sm

ythi

i Bas

in.

25

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

018H

2Su

n El

evat

ion:

28.

4°A

ltit

ude:

273

9.66

km

crat

er w

alls

of

Al-

Bir

uni

have

bee

n ov

erla

id w

ith

thes

e st

riat

ions

and

wit

hth

ose

from

the

Sm

ythi

i Bas

in, s

o A

l-B

irun

i’s c

rate

r m

ust

have

for

med

bef

ore

thos

e ba

sins

. T

he m

are

surf

ace

in A

l-B

irun

i ha

s be

en a

ssig

ned

to t

he L

ate

Imbr

ian

Peri

od.

25

7Ea

ster

nBa

sins

Reg

ion

The

val

leys

and

rid

ges

cros

sing

Nep

er a

nd G

odda

rd r

adia

te f

rom

the

Sm

ythi

iB

asin

. C

oper

nica

n cr

ater

God

dard

A (

12 k

m,

just

nor

th o

f G

odda

rd)

has

spre

ad i

ts r

ay p

atte

rn a

s fa

r as

Mar

e M

argi

nis.

The

nor

thw

est

to s

outh

east

stri

atio

ns i

n th

e vi

cini

ty o

f G

odda

rd a

re r

adia

l to

the

Im

briu

m B

asin

. T

he

Jolio

t’s c

entr

al p

eaks

form

wha

t m

ay b

e th

e be

ginn

ing

of a

n in

ner

ring

. Jol

iot

and

Hub

ble

have

had

thei

r flo

ors

flood

ed w

ith

lava

, des

pite

bei

ng fa

r fr

om a

nym

asco

n th

at m

ay m

ark

a pl

ume

from

the

man

tle.

Str

iati

ons

on th

e no

rthe

ast-

ern

wal

l of

Jol

iot

are

from

the

far

sid

e cr

ater

Lya

puno

v (a

djac

ent

and

muc

h

LO4-

018H

3Su

n El

evat

ion:

28.

4°A

ltit

ude:

273

9.66

km

youn

ger)

, who

se fl

oor

is a

lso

flood

ed w

ith

lava

. Ver

y lit

tle

mar

e m

ater

ial

isin

volv

ed b

ecau

se t

he c

rate

rs a

re n

ot f

ully

floo

ded.

The

cru

st i

s th

icke

r he

re,

alon

g th

e ea

ster

n li

mb,

and

tha

t m

ay e

xpla

in w

hy r

elat

ivel

y li

ttle

lav

a is

avai

labl

e.

25

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

cen

ter

of t

he A

ustr

ale

Bas

in (

52°

S, 9

5°E)

is

near

the

uppe

r le

ft c

orne

r of

thi

s ph

oto.

The

cir

cula

r se

gmen

t of

ari

dge

pass

ing

thro

ugh

Prie

stly

and

Leb

edev

is

an i

nner

rin

gof

this

bas

in. T

he b

asin

is o

bvio

usly

ver

y ol

d (P

re-N

ecta

rian

);m

any

crat

ers

of v

ario

us le

vels

of d

egra

dati

on h

ave

impa

cted

its

floor

. Kug

ler

and

near

by c

rate

rs h

ave

been

floo

ded

wit

hla

va, r

esur

faci

ng t

hose

are

as m

uch

late

r (e

spec

ially

in t

erm

sof

cra

ter

coun

ts)

than

the

form

atio

n of

the

floor

of t

he b

asin

.C

lem

enti

ne e

leva

tion

dat

a sh

ow th

is s

outh

ern

port

ion

of th

eba

sin

floor

to b

e hi

gher

than

the

nort

hern

floo

r.

LO4-

009H

1Su

n El

evat

ion:

24.

8°A

ltit

ude:

298

9.14

km

25

9Ea

ster

nBa

sins

Reg

ion

Ejec

ta o

f Lat

e Im

bria

n cr

ater

Jenn

er o

verl

ies

the

mar

e m

ater

-ia

l her

e, b

ut la

va fl

oodi

ng t

he fl

oor

of G

um h

as i

nter

rupt

edth

e se

cond

ary

field

of

Jenn

er,

and

Jenn

er i

tsel

f is

floo

ded.

App

aren

tly

Jenn

er i

mpa

cted

Mar

e A

ustr

ale

betw

een

two

orm

ore

lava

floo

ding

eve

nts.

Ano

ther

exa

mpl

e of

two

Aus

tral

ela

va fl

ows

stra

ddlin

g a

crat

er e

vent

can

be

seen

in L

O4-

009H

3ne

ar H

umbo

ldt.

Like

the

Sou

th P

ole–

Aik

en B

asin

of

the

far

side

, the

Aus

tral

e B

asin

has

onl

y a

very

wea

k po

siti

ve g

ravi

tyan

omal

y, s

ugge

stin

g ei

ther

a w

eak,

dif

fuse

sou

rce

of la

va o

ris

osta

tic

adju

stm

ent

of t

he s

urfa

ce o

f th

ese

very

old

bas

ins:

perh

aps

the

crus

t was

sti

ll pl

asti

c w

hen

they

wer

e fo

rmed

.

LO4-

009H

2Su

n El

evat

ion:

24.

8°A

ltit

ude:

298

9.14

km

26

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

A s

ecto

r of

the

mai

n ri

ng o

f th

e A

ustr

ale

Bas

in p

asse

sbe

twee

n A

bel

and

Bar

nard

, fo

rmin

g th

e no

rthe

rn s

hore

of

Mar

e A

ustr

ale.

The

sec

onda

ry fi

eld

of L

ate

Imbr

ian

crat

erH

umbo

ldt h

as b

een

cove

red

by a

you

ng m

are

flow

. Com

pare

this

wit

h th

at o

f Je

nner

(LO

4-00

9H2)

. Nei

ther

Bar

nard

nor

its

smal

ler

com

pani

on to

the

sout

h do

min

ates

the

crat

er w

all

betw

een

them

, sug

gest

ing

a si

mul

tane

ous

impa

ct. A

bel

has

had

its

wal

l pu

shed

ont

o it

s flo

or b

y B

arna

rd’s

com

pani

on.

Mar

ie C

urie

(bo

rn S

klod

owsk

a) a

nd h

er h

usba

nd P

ierr

eC

urie

rec

eive

d a

Nob

el P

rize

for

stu

dies

of

radi

oact

ivit

y.A

fter

Pie

rre’

s de

ath,

Mar

ie w

on a

sec

ond

Nob

el P

rize

for

the

disc

over

y of

rad

ium

and

pol

oniu

m (

see

LO4-

165H

3 fo

r m

ore

Cur

ie fa

mily

his

tory

).

LO4-

009H

3Su

n El

evat

ion:

24.

8°A

ltit

ude:

298

9.14

km

26

1Ea

ster

nBa

sins

Reg

ion

The

pla

n fo

r Lu

nar

Orb

iter

Mis

sion

4 w

as t

o ta

ke e

xten

sive

hig

h-re

solu

tion

phot

os o

f th

e ea

ster

n lim

b. H

owev

er, m

any

of t

hese

pho

tos

wer

e lo

st, e

spe-

cial

ly in

the

sout

h, b

ecau

se o

f the

failu

re o

f the

lens

cap

. Thi

s m

ediu

m-r

esol

u-ti

on p

hoto

fro

m L

unar

Orb

iter

Mis

sion

2 (

also

sho

wn

in F

igur

e 10

.3)

ispr

ovid

ed t

o fil

l in

the

gap

and

loca

te t

he n

amed

fea

ture

s ne

ar t

his

part

of

the

limb.

The

sou

thea

st s

ecto

r of

the

mai

n ri

ng o

f th

e Sm

ythi

i Bas

in c

an b

e se

en

LO2-

196M

Sun

Elev

atio

n: 1

9.9°

Alt

itud

e: 1

519.

03 k

m

ente

ring

the

phot

o at

the

top

and

curv

ing

arou

nd to

war

d th

e le

ft e

dge.

The

re is

a m

asco

n be

low

Mar

e Sm

ythi

i (w

hich

nea

rly

fills

an

inne

r ri

ng o

f th

e ba

sin)

but

not

belo

w M

are

Mar

gini

s. B

eyon

d th

e m

ain

ring

lies

the

tra

nsit

ion

to t

hehi

ghla

nd r

egio

n of

the

far

side

, wit

h it

s th

icke

r cr

ust.

Lacu

s So

litud

inus

may

be

a pa

rt o

f th

e sp

otty

ext

rusi

ons

of m

are

mat

eria

l ass

ocia

ted

wit

h th

e A

ustr

ale

Bas

in to

the

sout

h.

26

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

11.1. OverviewThe North Polar Region covers the area between the NorthPole and about 55° south latitude and between the westernand eastern limbs.

Mare Frigoris extends along the southern boundary of theregion. The area near the pole is heavily cratered highlands.Mare Humboldtianum is near the eastern limb of this regionat the center of the Humboldtianum Basin.

Mare FrigorisMare Frigoris (Figure 11.1) extends about 1500 km in theeast-west direction but only about 300 km in the north-southdirection. Its western section is clearly circumferential to theImbrium Basin, filling the outer trough of that basin. It con-nects with Sinus Roris, a large bay at the northern extremityof Oceanus Procellarum. The eastern section of MareFrigoris is northeast of the Serenitatis Basin. The lava surfaceof Mare Frigoris connects to that of Mare Serenitatis throughLacus Somniorum.

Chapter 11

North Polar Region

Figure 11.1. Mare Frigoris (LO4-190M). The white dashed lines are the 90° W and 0° E/W meridians. Mare Frigoris is the dark area stretching around theNorth Pole, a little more than halfway to the edge of the Moon. Mare Imbrium is near the bottom of the photo and Mare Serenitatis is to its right.

26

3N

ort

h

Pola

r R

egio

n

The Humboldtianum BasinThe Humboldtianum Basin (Figure 11.2), near the northeast-ern limb of the Moon, is a ringed basin that, like theOrientale and Nectaris Basins, is sufficiently far fromyounger basins that its structure is well preserved. Theringed structure can be seen in LO4-065H1 in this chapter.

The North Polar HighlandsThe heavily cratered region at the polar cap (see Figures 11.1and 11.2) extends across the pole into the far side highlands.The crust is thicker here, relative to the mare-filled areas tothe south. Even though there are large craters (not quitebasin sized), there is no sign of lava flooding beyond 70°north latitude on either the near side or far side.

The North PoleThe best parts of the photos taken near the North Pole oneach of the orbits of Clementine have been carefully assem-bled and are shown in Figure 11.3.

The highest points in this area, such as on the rims of largecraters, are in sunlight all or nearly all the time because theaxis of the Moon is within 1.5° of a right angle to the plane of

its travel around the sun (the ecliptic plane). Such a site isespecially interesting for a long-term base on the Moonbecause continuous or nearly continuous solar cell powerwould be available. Conceivably, solar panel farms could beestablished there (or near the South Pole) and the powercould be beamed to Earth.

Nearby, on the floors of smaller, deeper craters withinRozhdesvenskiy and Peary, there are very cold areas thatnever receive light or heat from the sun (see Chapter 12).Analysis of data from the neutron spectrometer instru-ments on the Lunar Prospector spacecraft has detected de-posits of hydrogen in the vicinity of these cold traps nearboth poles. If the hydrogen is in water molecules, it is inthe form of crystals distributed in the lunar soil, not assolid ice. The neutron spectrometer detects the energy ofsolar wind neutrons that rebound from the nuclei of atomson the lunar surface. A neutron that rebounds from thesingle proton in the nucleus of a hydrogen atom loses muchmore energy than if it rebounds from a nucleus of a heavierelement.

See the overview in the chapter on the South Polar Region(Chapter 12) for a discussion of how these hydrogen concen-trations can be used.

11.2. High-Resolution ImagesThe Lunar Orbiter photos of the North Polar Region, likethose of the South Polar Region, have a high degree ofoverlap because they were taken from a near-polar orbit. Allthe rectangular sets of three subframes in a high-resolutionexposure have the pole in or near the top of the northernsubframe. The illumination angle in the middle subframes isabout 10° but the angle approaches zero toward the pole. Ofcourse, the pole is always within 1.5° of the terminator.

Although the polar photos were not taken on every orbitover the poles, there is still so much overlap in the middleand northern subframes that only every other photo isprinted here (all the photos are in the enclosed CD). Table11.1 shows the high-resolution images of the North PolarBasin Region in schematic form.

The following pages show the high-resolution subframesfrom south to north and west to east. The photos are in theorder LO4-190H1, LO4-190H2, LO4-190H3, LO4-178H1,LO4-164H1, LO4-164H2, …. The last photo is LO4-165H1, anapolune photo.

To fill in an area in the southwestern part of the NorthPolar region, which was not photographed in high resolu-tion, the first following page shows medium-resolutionphoto LO4-189M. The planned high-resolution LunarOrbiter photos of the far eastern part of the North PolarRegion were spoiled by the failure of the thermal door. Nearthe end of the mission, apolune photos were taken of thatarea. One of these (LO4-165H1) is presented at the end ofthis chapter to complete coverage of the near side NorthPolar Region.

Figure 11.2. Humboldtianum Basin (LO4-128M). The black dashed linesmark the 0° E/W and 90° E meridians. The small dark area in the upper rightof this picture (near the 90° E meridian) is Mare Humboldtianum in thefloor of the Humboldtianum Basin. The basin structure is obscured in thisphoto by the bright ejecta and rays of the nearby Copernican craterBelkovitch. The large dark area near the bottom left of the picture is MareImbrium; Mare Serenitatis is to the east. Mare Frigoris is north of the twomaria.

26

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

26

5N

ort

h

Pola

r R

egio

n

75 N–90 N 190H3 176H3 164H3 152H1 140H3 128H1 116H3 104H1 092H3 080H1 068H3 165H1

60 N–75 N 190H2 176H2 164H2 152H1 140H2 128H1 116H2 104H1 092H2 080H1 068H2

50 N–60 N 190H1 176H1 164H1 152H1 140H1 128H1 116H1 104H1 092H1 080H1 068H1

27 N–56 N 189, 175, 163, 151, 175, 139, 127, 115, 103, 091, 079, 067, 055 165H2183 170 158 145 170 134 122 110 098 086 074 062

Longitude at 75 W 63 W 51 W 38 W 22 W 12 W 0 E/W 7 E 15 E 28 E 42 E 56 E 66 E 85 E50 N

Table 11.1. The cells shown in white represent the high-resolution Lunar Orbiter photos of the North Polar Region (LO4-XXX H1, -H2, and -H3, whereXXX is the Photo Number). The shaded cells within the North Polar Region represent photos that are not printed in this chapter because of redundancy; theyare included in the CD. South of this region are the Imbrium Basin Region, the Serenitatis Basin Region, and the Eastern Basins Region. Exposure 165H1 wastaken from apolune in afternoon sun. The apolune photo was taken at about twice the altitude of perilune photos, so it has about half the resolution and fourtimes the area of coverage.

Figure 11.3. North Pole (USGS Astrogeology, PIA00002, NASA). This mosaic covers the North Polar Region within 10° of the pole. The near side is in thelower half of the photo.

Bec

ause

of

the

desi

gn o

f Lu

nar

Orb

iter

Mis

sion

4,

the

spac

ecra

ft o

rbit

was

tilt

ed s

light

ly t

owar

d th

e ea

st o

f th

e N

orth

Pol

e. A

s a

resu

lt, h

igh-

reso

luti

onph

otos

of

the

wes

tern

par

t of

the

Nor

th P

olar

Reg

ion

are

not

avai

labl

e. T

hem

ediu

m-r

esol

utio

n ph

oto

abov

e is

pro

vide

d to

fill

in t

his

area

and

sho

w t

helo

cati

on o

f th

e na

med

fea

ture

s w

ithi

n it

. T

he m

are

surf

ace

of n

orth

ern

Oce

anus

Pro

cella

rum

is d

omin

ated

by

the

ray

patt

ern

of a

sm

all c

rate

r so

uth

ofPy

thag

oras

(LO

4-19

0H1)

. T

he s

ubdu

ed n

atur

e of

the

top

ogra

phy

near

the

wes

tern

sho

re o

f O

cean

us P

roce

llaru

m m

ay b

e du

e to

an

oute

r tr

ough

of

the

prop

osed

Lav

oisi

er-M

aira

n B

asin

.LO4-

189

MSu

n El

evat

ion:

18.

4°A

ltit

ude:

287

7.87

km

26

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

mar

e in

the

low

er p

art

of t

his

phot

o flo

ods

two

larg

ecr

ater

s, o

ne b

etw

een

Oen

opid

es a

nd R

epso

ld a

nd a

noth

er to

the

sout

heas

t of

Rep

sold

. Py

thag

oras

is

an e

xam

ple

of a

youn

g Er

atos

then

ian

crat

er; t

here

is d

etai

led,

sha

rply

del

in-

eate

d st

ruct

ure

in i

ts c

rate

r w

all a

nd e

ject

a bl

anke

t, bu

t th

era

y st

ruct

ure

has

been

sup

pres

sed

by a

com

bina

tion

of

gard

enin

g by

met

eor

impa

cts

and

dark

enin

g by

the

sol

arw

ind.

The

ray

s in

this

are

a, e

xten

ding

into

nor

ther

n O

cean

usPr

ocel

laru

m, a

re d

ue t

o a

smal

l cr

ater

on

the

nort

h ri

m o

fO

enip

edes

. N

ote

the

seco

ndar

y fie

ld o

f Py

thag

oras

in

the

vici

nity

of O

enop

ides

.

LO4-

190H

1Su

n El

evat

ion:

13.

5°A

ltit

ude:

337

8.38

km

26

7N

ort

h

Pola

r R

egio

n

Pyth

agor

as h

as s

prea

d it

s ej

ecta

bla

nket

to

the

wes

t an

dno

rth

as w

ell

as t

o th

e so

uth

(LO

4-19

0H1)

. In

the

nort

hern

lati

tude

s, a

bove

70°

from

the

equ

ator

, th

e te

rrai

n be

com

escl

earl

y hi

ghla

nd, w

ith

crat

ers

of e

very

siz

e ov

erla

ppin

g.

LO4-

190H

2Su

n El

evat

ion:

13.

5°A

ltit

ude:

337

8.38

km

26

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s is

the

wes

tern

app

roac

h to

the

Nor

th P

ole.

Her

mit

e,de

eply

sha

dow

ed i

n th

is p

ictu

re,

is a

bout

to

have

its

floo

rill

umin

ated

wit

h su

nlig

ht. N

ear

the

Nor

th P

ole,

the

sun

does

not i

llum

inat

e pa

rts

of c

rate

r flo

ors

duri

ng e

ntir

e lu

nar

rota

-ti

ons

(mon

ths)

. H

owev

er,

the

sun

illum

inat

es m

ore

of t

heflo

ors

over

a y

ear’

s ti

me

beca

use

of t

he s

ligh

t ti

lt o

f th

eM

oon’

s ax

is r

elat

ive

to th

e ec

lipti

c pl

ane.

You

ng, s

harp

, sm

all

crat

ers

near

the

pol

e ha

ve m

ore

of t

heir

floo

rs p

erm

anen

tly

dark

bec

ause

the

y ar

e re

lati

vely

dee

p an

d th

eir

floor

s ar

em

ore

shad

ed b

y th

eir

rim

s th

an t

he fl

oors

of

old,

deg

rade

d,la

rge

crat

ers.

LO4-

190H

3Su

n El

evat

ion:

13.

5°A

ltit

ude:

337

8.38

km

26

9N

ort

h

Pola

r R

egio

n

The

anc

ient

cra

ter

Bab

bage

has

influ

ence

d th

e fo

rmat

ion

ofth

e Py

thag

oras

cra

ter

in th

is a

rea.

cra

ter

Sout

h, a

ltho

ugh

rel-

ativ

ely

degr

aded

in

com

pari

son

to B

abba

ge, i

s ne

vert

hele

ssyo

unge

r, b

ecau

se a

sec

tor

of it

s w

all t

rave

rses

Bab

bage

. Sin

usR

oris

has

thi

nly

flood

ed t

his

regi

on, l

eavi

ng t

race

s of

cra

ter

wal

ls s

uch

as t

hat

sout

heas

t of

Mar

kov.

Sec

onda

ry c

rate

rsfr

om P

ytha

gora

s ha

ve f

alle

n on

muc

h of

thi

s ar

ea.

A m

are

unit

(so

uth

of c

rate

r So

uth)

has

floo

ded

part

of t

he s

econ

dary

field

of P

ytha

gora

s, s

how

ing

that

mar

e un

it fo

rmed

late

r.B

oth

Pyth

agor

as a

nd t

he m

are

unit

are

ass

igne

d to

the

Erat

osth

enia

n Pe

riod

.

27

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

176H

1Su

n El

evat

ion:

12.

8°A

ltit

ude:

335

3.98

km

The

are

a no

rth

of M

are

Frig

oris

, suc

h as

the

floor

s of

cra

ters

Sout

h an

d J.

Her

sche

l, is

hea

vily

cov

ered

wit

h ej

ecta

from

the

Imbr

ium

Bas

in t

o th

e ea

st-s

outh

east

. In

par

ticu

lar,

rid

ges

and

valle

ys i

n th

e cr

ater

wal

l of

J.

Her

sche

l po

int

to t

hece

nter

of

the

Imbr

ium

Bas

in. T

he c

rate

r ch

ain

in t

he s

outh

-ea

ster

n flo

or o

f cr

ater

Sou

th i

s lik

ely

to b

e fo

rmed

by

sec-

onda

ry i

mpa

ctor

s fr

om a

cra

ter

that

has

bee

n flo

oded

by

Sinu

s Ir

idum

(to

the

sout

heas

t).

LO4-

164H

1Su

n El

evat

ion:

12.

9°A

ltit

ude:

334

5.81

km

27

1N

ort

h

Pola

r R

egio

n

The

int

eres

ting

hig

hlan

d pl

ains

bet

wee

n J.

Her

sche

l an

dA

naxi

men

es h

ave

a m

ottl

ed a

ppea

ranc

e be

caus

e th

ey h

ave

been

ove

rlai

n w

ith

rays

fro

m C

oper

nica

n cr

ater

s C

arpe

nter

and

Philo

laus

. The

sm

ooth

app

eara

nce

of t

his

area

cou

ld b

edu

e to

unc

onso

lida

ted

ejec

ta f

rom

the

Im

briu

m B

asin

,sh

aken

dow

n an

d co

nsol

idat

ed b

y th

e la

ter

impa

cts

ofC

arpe

nter

and

Phi

lola

us,

whi

ch c

ould

hav

e be

en v

irtu

ally

sim

ulta

neou

s. O

r, s

ome

maj

or t

ecto

nic

even

t co

uld

have

occu

rred

in th

is a

rea

to s

hake

dow

n th

e ej

ecta

bla

nket

.

LO4-

164H

2Su

n El

evat

ion:

12.

9°A

ltit

ude:

334

5.81

km

27

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

164H

3Su

n El

evat

ion:

12.

9°A

ltit

ude:

334

5.81

km

27

3N

ort

h

Pola

r R

egio

n

The

hea

vy r

idge

s an

d va

lleys

sou

th o

f B

yrd

and

Gio

ja a

rera

dial

to

the

Imbr

ium

Bas

in,

part

of

its

oute

r de

posi

t. T

hecl

uste

r of

sha

rp c

rate

rs in

the

10-

to

15-k

m r

ange

of

diam

e-te

rs in

the

sou

ther

n pa

rt o

f th

is a

rea

coul

d ha

ve c

ome

from

Imbr

ium

. A

lter

nati

vely

, th

ey c

ould

hav

e be

en c

ause

d by

asa

lvo

of s

econ

dari

es fr

om th

e fa

r si

de c

rate

r R

ozhd

estv

ensk

iyco

min

g ov

er th

e N

orth

Pol

e.

The

rin

g of

the

Im

briu

m B

asin

tha

t bo

unds

Mar

e Im

briu

m p

asse

s be

twee

nBo

ugue

r an

d Bi

anch

ini.

Its

cros

shat

ched

cha

ract

er m

ay b

e du

e to

fine

-tex

ture

dej

ecta

fro

m t

he c

rate

r be

neat

h Si

nus

Ror

is o

verl

ying

the

coa

rser

rid

ges

and

valle

ys c

ause

d by

the

Imbr

ium

eve

nt. T

he d

ark

area

in th

e ea

ster

n pa

rt o

f Mar

eFr

igor

is i

n th

is p

hoto

is

typi

cal

mar

e m

ater

ial,

whi

ch h

as fl

oode

d an

out

er

27

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

152H

1Su

n El

evat

ion:

13.

0°A

ltit

ude:

339

4.33

km

trou

gh o

f the

Im

briu

m B

asin

. In

the

east

, Mar

e Fr

igor

is a

ppea

rs t

o ha

ve b

een

cove

red

wit

h a

laye

r of

lig

hter

ray

ed m

ater

ial,

prob

ably

fro

m C

oper

nica

ncr

ater

Ana

xago

ras

(LO

4-14

0H2)

. U

nder

neat

h th

is c

ould

be

ejec

ta f

rom

Philo

laus

, als

o C

oper

nica

n.

The

rin

g of

the

Im

briu

m B

asin

tha

t bo

unds

its

mar

e pa

sses

betw

een

La C

onda

min

e an

d M

aupe

rtui

s. R

imae

Mau

pert

isar

e ou

tflow

cha

nnel

s or

col

laps

ed la

va t

ubes

whe

re la

va h

asco

me

up t

hrou

gh t

he r

ing

and

flow

ed n

orth

int

o M

are

Frig

oris

and

sou

th in

to M

are

Imbr

ium

. Thi

s ty

pe o

f flow

sug

-ge

sts

that

upw

ellin

g la

va,

part

ially

blo

cked

by

mel

t sh

eets

and

earl

ier

lava

flow

s (n

ow h

arde

ned)

, can

find

its

way

up

thro

ugh

the

frac

ture

d ri

ng m

ater

ial a

nd th

en d

ownh

ill.

LO4-

140H

1Su

n El

evat

ion:

12.

5°A

ltit

ude:

335

5.14

km

27

5N

ort

h

Pola

r R

egio

n

Philo

laus

and

Ana

xago

ras

are

Cop

erni

can

crat

ers.

Ana

xa-

gora

s, i

n pa

rtic

ular

, ha

s im

pact

ed u

ncon

solid

ated

mat

eria

lon

the

rim

of

Gol

dsch

mid

t an

d ej

ecte

d pa

rtic

ular

ly m

assi

veflo

ws

of fi

nely

bro

ken

mat

eria

l th

at s

moo

ths

the

floor

of

Gol

dsch

mid

t an

d th

e ar

ea s

outh

of G

olds

chm

idt.

The

se r

ays

exte

nd to

Mar

e Fr

igor

is (

LO-1

52H

1). T

ecto

nic

forc

es a

nd th

esh

ock

of th

e im

pact

of A

naxa

gora

s m

ay a

lso

have

had

a p

art

in th

e le

velin

g of

the

plai

ns s

outh

of G

olds

chm

idt.

LO4-

140H

2Su

n El

evat

ion:

12.

5°A

ltit

ude:

335

5.14

km

27

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

rid

ges

that

com

e fr

om t

he s

outh

are

rad

ial

to t

heIm

briu

m B

asin

. O

ther

str

iati

ons

from

the

sou

th-s

outh

east

,fin

er in

text

ure,

are

rad

ial t

o th

e Se

reni

tati

s B

asin

. Mai

n an

dC

halli

s, t

wo

crat

ers

of a

ppro

xim

atel

y th

e sa

me

size

and

age

,co

uld

have

bee

n ca

used

by

near

ly s

imul

tane

ous

impa

cts.

Alt

houg

h M

ain

has

impi

nged

on

the

Cha

llis

rim

, the

eje

cta

blan

ket o

f Cha

llis

appe

ars

to h

ave

been

bet

ter

pres

erve

d. T

hear

ea i

mm

edia

tely

to

the

wes

t of

Mai

n an

d C

halli

s ha

s be

ende

pres

sed

and

smoo

thed

, wit

h al

l sig

ns o

f ej

ecta

fro

m M

ain

and

Cha

llis

eras

ed. T

ecto

nic

acti

on b

enea

th a

thi

ck u

ncon

-so

lidat

ed s

urfa

ce la

yer

coul

d be

the

cau

se. R

ober

t Pe

ary

led

an e

xped

itio

n of

50

Eski

mos

and

rea

ched

the

Nor

th P

ole

bydo

gsle

d in

190

9. R

icha

rd E

. B

yrd

flew

ove

r th

e N

orth

Pol

ew

ith

Floy

d B

enne

tt in

192

6. H

e la

ter

flew

ove

r th

e So

uth

Pole

in 1

929.

He

was

an

acti

ve e

xplo

rer

of A

ntar

ctic

a by

air

plan

esan

d do

gsle

ds fr

om 1

928

to 1

956.

LO4-

140H

3Su

n El

evat

ion:

12.

5°A

ltit

ude:

335

5.14

km

27

7N

ort

h

Pola

r R

egio

n

Thi

s ar

ea o

f M

are

Frig

oris

is

rich

in

ridg

es a

nd s

carp

s(p

erha

ps t

he e

dges

of

flow

s).

Its

surf

ace

expr

essi

on i

spi

nche

d be

twee

n th

e ej

ecta

of P

lato

and

the

hig

hlan

d pe

nin-

sula

nor

th o

f it

. Bot

h Pl

ato

and

the

Irid

um c

rate

r ar

e da

ted

in t

he U

pper

Im

bria

n Ep

och.

The

sec

onda

ry fi

eld

of P

lato

seem

s to

ove

rlie

the

Iri

dum

eje

cta,

esp

ecia

lly t

o th

e no

rth-

east

, but

str

iati

ons

from

Iri

dum

see

m t

o ov

erlie

Pla

to e

ject

aju

st t

o th

e no

rth

and

sout

h of

its

rim

. Pla

to’s

floo

r ha

s be

enflo

oded

wit

h m

are

mat

eria

l, up

wel

ling

thro

ugh

the

brok

enm

ater

ial o

f the

mai

n ri

ng o

f the

Imbr

ium

Bas

in.

LO4-

128H

1Su

n El

evat

ion:

11.

7°A

ltit

ude:

336

9.17

km

27

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Just

to

the

east

of

Plat

o th

ere

is m

ore

evid

ence

of

lava

up-

wel

ling

thro

ugh

the

brok

en m

ater

ial o

f th

e m

ain

ring

of

the

Imbr

ium

Bas

in.

Rim

ae P

lato

dra

in p

ools

of

dark

lav

a in

tola

rger

cha

nnel

s su

ch a

s V

allis

Alp

es. V

allis

Alp

es m

ay b

e a

stre

ss c

rack

rad

ial t

o th

e Im

briu

m B

asin

that

has

bee

n ne

arly

fille

d w

ith

lava

. A la

va c

hann

el r

uns

thro

ugh

its

cent

er. T

heno

rthe

rn p

art

of R

imae

Pla

to s

eem

s to

dis

appe

ar a

nd r

e-ap

pear

; it

is p

roba

bly

a ch

anne

l in

som

e se

ctor

s an

d an

un-

derg

roun

d tu

be in

oth

ers.

Gar

deni

ng b

y im

pact

ors

may

hav

ebr

oken

thro

ugh

the

roof

of t

he tu

bes

in s

ome

sect

ors,

leav

ing

chan

nels

.

LO4-

116H

1Su

n El

evat

ion:

11.

6°A

ltit

ude:

339

6.94

km

27

9N

ort

h

Pola

r R

egio

n

The

coa

rse

ridg

es i

n th

is p

hoto

are

rad

ial

to t

he I

mbr

ium

Basi

n. T

he e

ject

a bl

anke

t of t

he Im

briu

m B

asin

cha

nges

cha

r-ac

ter

betw

een

W. B

ond

and

Met

on, s

hift

ing

from

the

thi

ckFr

a M

auro

For

mat

ion

to t

hinn

er o

uter

dep

osit

s. C

oper

nica

ncr

ater

Ana

xago

ras

send

s it

s ra

ys a

cros

s Pr

e-N

ecta

rian

Gol

dsch

mid

t, W

. Bon

d, B

arro

w, a

nd M

eton

. The

cra

ter

wal

lof

Bar

row

is

mor

e po

lygo

nal

than

cir

cula

r. I

t ha

s be

enst

rong

ly i

nflue

nced

by

pree

xist

ing

stru

ctur

es i

n it

s ta

rget

area

. For

exa

mpl

e, t

he c

rate

r w

all

seem

s to

be

furt

her

from

the

cent

er w

here

it p

enet

rate

s th

e br

oken

mat

eria

l of t

he r

imof

Gol

dsch

mid

t. R

ima

W. B

ond

runs

nea

rly

acro

ss c

rate

r W

.B

ond,

sug

gest

ing

uplif

t pr

essu

re b

enea

th a

mel

t sh

eet

unde

rit

s flo

or.

LO4-

116H

2Su

n El

evat

ion:

11.

6°A

ltit

ude:

339

6.94

km

28

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

low

sun

ele

vati

on o

f th

is p

hoto

nea

r th

e te

rmin

ator

at

the

pole

sho

ws

that

the

floor

of B

yrd

is v

ery

flat.

LO4-

116H

3Su

n El

evat

ion:

11.

6°A

ltit

ude:

339

6.94

km

28

1N

ort

h

Pola

r R

egio

n

The

eje

cta

from

Era

tost

heni

an c

rate

r A

rist

otel

es h

ave

been

laid

dow

n in

two

phas

es, s

epar

ated

by

only

min

utes

. The

firs

tph

ase

cons

iste

d of

fine

ly d

ivid

ed m

ater

ial

ejec

ted

at a

ver

ylo

w a

ngle

. T

his

form

atio

n ha

s sm

ooth

rad

ial

ridg

es a

ndtr

ough

s. S

ubse

quen

tly,

cha

ins

and

loop

s of

sm

all s

harp

sec

-on

dary

cra

ters

for

m f

rom

im

pact

ors

that

hav

e be

en t

hrow

nhi

gh a

bove

the

sur

face

and

land

aft

er t

he in

itia

l bla

nket

has

sett

led.

The

mar

e to

the

nor

th, s

till

part

of

Mar

e Fr

igor

is, i

sno

long

er in

the

Imbr

ium

trou

gh th

at li

es o

utsi

de o

f its

mai

nri

ng.

The

dep

ress

ion

that

has

bee

n flo

oded

to

form

the

east

ern

part

of

Mar

e Fr

igor

is m

ay h

ave

been

for

med

by

the

inte

rsec

tion

of t

he s

econ

d ou

ter

trou

ghs

of th

e Im

briu

m a

ndSe

reni

tati

s B

asin

s. O

f co

urse

, th

ese

circ

les

inte

rsec

t at

tw

opo

ints

; th

e ot

her

inte

rsec

tion

is

at S

inus

Med

ii,

anot

her

flood

ed d

epre

ssio

n.

LO4-

104H

1Su

n El

evat

ion:

12.

2°A

ltit

ude:

342

7.64

28

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Seve

ral c

lues

sug

gest

that

this

are

a of

Mar

e Fr

igor

is is

rel

ativ

ely

shal

low

. The

sein

dica

tion

s in

clud

e th

e pr

ojec

ting

rim

of

Gar

tner

and

its

fain

t co

mpa

nion

to

the

nort

hwes

t, th

e pr

esen

ce o

f so

man

y m

are

ridg

es, s

ome

wit

h ci

rcul

ar s

truc

-tu

re s

ugge

stin

g un

derl

ying

cra

ter

rim

s, a

nd t

he c

once

ntri

c pa

tter

n of

Gal

le,

28

3N

ort

h

Pola

r R

egio

n

LO4-

092H

1Su

n El

evat

ion:

12.

2°A

ltit

ude:

345

7.15

sugg

esti

ng t

hat

it h

as b

otto

med

out

int

o a

laye

r be

neat

h th

e m

are

mat

eria

l.T

he m

ajor

ity

of fl

ow s

carp

s dr

op t

owar

d th

e no

rthw

est,

sugg

esti

ng t

hat

this

area

was

floo

ded

from

the

sout

heas

t.

The

floo

rs o

f Met

on a

nd it

s si

mila

r co

mpa

nion

s ar

e no

t inh

eren

tly d

arke

r th

anth

e su

rrou

ndin

g m

ater

ial (

see

Figu

re 1

.3);

they

are

just

clo

ser

to th

e te

rmin

ator

.

28

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

092H

2Su

n El

evat

ion:

12.

2°A

ltit

ude:

345

7.15

28

5N

ort

h

Pola

r R

egio

n

LO4-

092H

3Su

n El

evat

ion:

12.

2°A

ltit

ude:

345

7.15

The

clu

ster

of s

econ

dary

cra

ters

eas

t of B

yrd

and

Pear

y m

ay in

clud

e im

pact

ors

from

eac

h of

the

Im

briu

m a

nd H

umbo

ldti

anum

Bas

ins;

the

pol

e is

abo

uteq

uidi

stan

t fro

m th

e ce

nter

of e

ach

basi

n, r

elat

ive

to th

eir

size

s. T

he la

rger

sec

-on

dari

es a

re li

kely

to b

e fr

om Im

briu

m a

nd th

e sm

alle

r fr

om H

umbo

ldti

anum

.C

ontr

ibut

ions

may

als

o ha

ve c

ome

over

the

pol

e fr

om f

ar s

ide

crat

erR

ozhd

estv

ensk

iy.

The

nor

thea

ster

n sh

ore

of M

are

Frig

oris

is

boun

ded

by a

high

land

pla

ins

unit

, fo

rmed

by

a du

sty

cove

ring

of

ejec

tafr

om t

he H

umbo

ldti

anum

Bas

in. D

e La

Rue

is ju

st o

utsi

de a

ring

of

Hum

bold

tian

um, p

roba

bly

the

mai

n ri

ng; t

hat

puts

this

are

a in

an

exte

rnal

trou

gh o

f the

bas

in. T

hat i

mpa

ct m

ayha

ve e

ssen

tial

ly l

evel

ed t

he h

ighl

and

mat

eria

l in

thi

s ar

eash

ortl

y be

fore

dep

osit

ion

of t

he p

ulve

rize

d ej

ecta

, w

hich

furt

her

smoo

thed

the

are

a. D

ark

man

tlin

g m

ater

ial,

ofte

nse

en n

ear

the

shal

low

edg

es o

f m

aria

, no

t on

ly c

over

s th

ispa

rt o

f Mar

e Fr

igor

is b

ut a

lso

dark

ens

the

near

by h

ighl

ands

.

28

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

080H

1Su

n El

evat

ion:

13.

0°A

ltit

ude:

347

9.03

Endy

mio

n an

d D

e La

Rue

are

just

out

side

the

650

km

mai

nri

ng o

f th

e H

umbo

ldti

anum

Bas

in,

in t

he fi

rst

exte

rnal

trou

gh (

see

LO4-

165H

1). B

oth

are

olde

r th

an t

hat

basi

n, b

utD

e La

Rue

mus

t be

old

er t

han

Endy

mio

n, j

udgi

ng b

y th

ere

lati

ve d

egre

e of

deg

rada

tion

. En

dym

ion

is c

lass

ified

as

Nec

tari

an. T

he b

righ

tnes

s co

veri

ng D

e La

Rue

, Str

abo,

and

the

surr

ound

ing

area

is

the

resu

lt o

f th

e fr

esh

ejec

ta f

rom

Cop

erni

can

crat

er T

hale

s (L

O4-

165H

1).

LO4-

068H

1Su

n El

evat

ion:

11.

5°A

ltit

ude:

348

7.74

28

7N

ort

h

Pola

r R

egio

n

The

mai

n ri

ng o

f th

e H

umbo

ldti

anum

Bas

in (

LO4-

165H

1)cr

osse

s di

agon

ally

acr

oss

the

low

er r

ight

cor

ner

of th

is p

hoto

,so

uth

of C

usan

us a

nd e

ast

of S

chw

abe.

Rad

ial

ridg

es a

ndva

lleys

of e

ject

a pa

ss b

etw

een

Baill

aud

and

Pete

rman

n. T

here

are

clus

ters

of

smal

l se

cond

arie

s on

the

floo

r of

Pet

erm

ann

and

the

very

deg

rade

d gr

oup

of t

hree

cra

ters

of

sim

ilar

size

to th

e w

est o

f Pet

erm

ann.

28

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

068H

2Su

n El

evat

ion:

11.

5°A

ltit

ude:

348

7.74

The

are

a of

the

righ

t sid

e of

this

pho

to is

dom

inat

ed b

y ej

ecta

from

the

Hum

bold

tian

um B

asin

. Som

e ri

dges

, at r

ight

ang

les

to t

hose

fro

m H

umbo

ldti

anum

, ar

e ra

dial

to

the

Imbr

ium

Bas

in. F

ridt

jof N

anse

n al

low

ed h

is s

peci

ally

con

stru

cted

shi

pFr

amto

be

froz

en in

to p

olar

ice

near

Sib

eria

in 1

993,

inte

nd-

ing

to d

rift

wit

h th

e ic

e to

war

d G

reen

land

. As

Fram

mad

e it

scl

oses

t ap

proa

ch t

o th

e po

le, N

anse

n an

d a

com

pani

on l

eft

the

ship

by

dogs

led

and

reac

hed

86°

13’

nort

h la

titu

de.

Nan

sen’

s le

ader

ship

in

prog

ram

s to

rep

atri

ate

pris

oner

s of

war

aft

er W

orld

War

I a

nd r

elie

f of

fam

ine

resu

lted

in

his

rece

ivin

g th

e N

obel

Pea

ce P

rize

in 1

922.

LO4-

068H

3Su

n El

evat

ion:

11.

5°A

ltit

ude:

348

7.74

28

9N

ort

h

Pola

r R

egio

n

The

rin

ged

stru

ctur

e of

the

Hum

bold

tian

um B

asin

can

cle

arly

be

seen

in t

his

apol

une

phot

o ta

ken

near

the

end

of

the

mis

sion

. M

are

Hum

bold

tian

umne

arly

fills

a r

ing

that

may

be

an in

ner

ring

. The

nex

t ri

ng is

sub

dued

in t

his

sect

or, b

ut t

he r

ing

afte

r th

at, r

unni

ng ju

st e

ast

of t

he r

ims

of D

e La

Rue

and

29

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

165H

1Su

n El

evat

ion:

13.

9°A

ltit

ude:

548

6.51

Stra

bo, m

ay b

e th

e m

ain

ring

. Mar

e pa

rtly

floo

ds t

he a

rea

betw

een

the

ring

boun

ding

the

mar

e an

d th

e m

ain

ring

. Rad

ial r

idge

s an

d va

lleys

, suc

h as

thos

ecr

ossi

ng th

e ri

m o

f Str

abo

and

both

nor

th a

nd s

outh

of M

are

Hum

bold

tian

um,

are

radi

al to

this

rin

ged

basi

n.

12.1. OverviewThe near side South Polar Region covers the area betweenabout 55° south latitude and the South Pole and between thewestern and eastern limbs.

The region is entirely highlands. On a large scale, itstopography records the early over-cratered bombardment ofthe Moon after the crust formed. The entire South PolarRegion is within one diameter of the main ring of the SouthPole–Aiken Basin on the far side, so it has been essentiallycovered with ejecta from that basin. However, that ejecta hasbeen so degraded by further bombardment that it is difficultto identify specific features such as ridges and secondarycraters that might have been due to the South Pole–Aikenimpact.

Western Sector of the South PolarRegionThe Bailly Basin, unflooded by mare, is within this sector,toward the western limb (Figure 12.1). The lack of mareflooding is an indicator of a relatively thick crust in this area.

Central Sector of the South PolarRegionFigure 12.2 shows the central part of the near side SouthPolar Region. The highlands here are a continuation of thenear side central highlands, a feature that reaches all the wayto the lunar equator.

Eastern Sector of the South PolarRegionFigure 12.3 shows the eastern limb of the Moon, includingthe eastern edge of the near side South Polar region. Thesouthern part of the Australe Basin is in this sector.

The South PoleThe best parts of the photos taken near the South Pole oneach of the orbits of Clementine have been carefully assem-bled and are shown in Figure 12.4.

As can be seen from Figure 12.4, the sun is rarely seen atthe floors of craters that are deep relative to their sizebecause the lunar axis is inclined by only 1.5° relative to theplane of its travel around the sun. More of this permanentlyshadowed area is near the South Pole than near the North

Pole. As the surface is radiating heat to deep space andbecause the dusty surface (gardened by small meteorites) is areasonably good insulator against thermal conductivity, thetemperature at the floors of these craters is near absolutezero, as low as 40 degrees Kelvin. The surface dust at suchcold ambient temperatures is a good trap for volatiles suchas hydrogen that arrive there by chance. Hydrogen is avail-able from the solar wind, in the form of ionized protons.Such protons that impact in sunlit areas on the Moon arelikely to be neutralized and thermally excited into the space

29

1So

uth

Pola

r R

egio

n

Chapter 12

South Polar Region

Figure 12.1. Western Sector of the South Polar Region (LO4-193M). Thewhite dashed line marks the western limb, the meridian at 90° degrees westlongitude. The Bailly ringed basin is in the center of this photo, in the north-ern part of the South Polar Region. The 90° meridian runs through the craterHausen, adjacent to Bailly. The Orientale Basin is to the north, near thevisible edge of the Moon in this photo. Ridges of Orientale ejecta can be seenreaching all the way to the edge of the South Polar Region.

around the Moon. If they do not escape, they “hop” fromplace to place (landing and being reemitted).

The Lunar Prospector Mission carried instruments todetect concentrations of hydrogen and found them near eachof the poles. The hydrogen, perhaps combined with oxygen(plentiful in the minerals of the lunar surface) in the form ofice, is likely to have been trapped at or near the surface ofthese permanently shadowed areas.

The nature of these concentrations of hydrogen andperhaps of ice is of great interest. If sufficiently rich concen-trations of suitable materials can be found in the low gravityof the Moon, they might provide a useful source of rocketfuel or propellant, rather than lifting supplies from Earth.

Another special characteristic of this region near the poleis its location near the South Pole–Aiken Basin. Rocks scat-tered here could be the deepest ever excavated from the crust(and possibly from the upper mantle of the Moon). An expe-dition to gather these rocks could also establish the age ofthe oldest lunar basin and help determine whether basinbombardment was continuous from the time of thesolidification of the crust or whether there was a separate,later event of basin bombardment.

12.2. High-Resolution ImagesThe Lunar Orbiter photos of the South Polar Region (Table12.1), like those of the North Polar Region, have a highdegree of overlap because they were taken from a near polarorbit. The rectangular sets of three subframes in a high-reso-lution exposure taken at perilune have the pole in or near thebottom of the southern subframe (designated H1). The illu-mination angle in the more northern subframes (H2 and H3)is about 10°, but the angle approaches 0 toward the pole. Ofcourse, the pole is always within 1.5° of the terminator. Theactual South Pole was in shadow during this mission.

Although the polar photos were not taken on every orbitover the poles, there is still so much overlap in the middleand southern subframes that only every other photo isshown here.

After an early success (LO4-005H1, -H2, and -H3). theplanned high-resolution photos of the eastern South PolarRegion were spoiled by the failure of the thermal door. Nearthe end of the mission, apolune photos were taken of thatarea. One subframe of these (LO4-184H3) is presented nearthe end of this chapter to provide complete coverage of thenear side South Polar Region. Table 12.1 shows the high-reso-lution images of the South Polar Region in schematic form.

The following pages show the high-resolution subframesfrom south to north and west to east. The photos are in theorder LO4-193H1, LO4-193H2, LO4-193H3, LO4-179H3,LO4-186H1, LO4-186H2, …. After LO4-184H3, an apolunephoto, are LO4-005H1, LO4-005H2, and LO4-005H3.

29

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Figure 12.2. Central South Polar Region (LO4-106M). The dashed line isthe zero meridian. The small dark area in the upper left corner of thispicture is Mare Nubium, in the floor of the Nubium Basin. The very sharpcrater south of Mare Nubium is Tycho, which spreads its rays preferentiallyto the east, over the southern part of the near side central highlands. Thelarge crater Clavius is directly to the south of Tycho, just within the SouthPolar Region. The bright area southeast of the center of the photo is due tothe ejecta of Copernican crater Stevinus. The dark splotchy area in the lowerright is the western portion of Mare Australe. The shadowed floor of thesmall far side Schrodinger Basin is below and to the right of the South Pole.

Figure 12.3. Eastern South Polar Region (LO4-008M). The dashed line isthe eastern limb, the 90° east meridian. Mare Australe is in the upper left.The smaller Schrodinger Basin is below it, with deep valleys runningbetween it and the Australe Basin.

27 S–56 S N 194, 180, 167, 155, 142, 124, 112, 100, 188, 076, 064, 076, 184H1, 178H1, 009186 172 160 148 136, 119 107 095 083 071 059 071 H2 H2

131

55S–65S 193H3 179H3 166H3 154H3 130H3 118H3 106H3 094H3 082H3 070H3 058H3 044H3 184H3 178H3 005H3

65 S–75 S 193H2 179H2 166H2 154H2 130H2 118H2 106H2 094H2 082H2 070H2 058H2 044H2 005H2

75 S–90 S 193H1 179H1 166H1 154H1 130H1 118H1 106H1 094H1 082H1 070H1 058H1 044H1 005H1

Longitude 90 W, 70 W 60 W, 50 W, 40 W, 10 W 0 E/W, 20 E 30 E 40 E 50 E 60 E 50 E, 60 E, 80 E, at 50 S 80 W 50 W 40 W 30 W, 10 E 70 E 90 E

20 W

Table 12.1. The cells shown in white represent the high-resolution photos of the South Polar Region that are printed in this chapter (LO4-XXX H1, -H2, and-H3, where XXX is the Photo Number). The shaded cells within the South Polar Region represent photos that are not shown in this chapter because of redun-dancy; however, they are in the included CD. North of this region are the Orientale Basin Region, the Humorum Basin Region, the Nectaris Basin Region, andthe Eastern Basin Region. Exposure 184H3 was taken from apolune in afternoon sun.

Figure 12.4. South Pole (USGS Astrogeology PIA00002, NASA). This mosaic covers the South Polar Region within 10° of the pole. The near side is in theupper half of the photo. Crater Shoemaker, near the pole, was in shadow throughout the Lunar Orbiter 4 and Clementine Missions.

29

3So

uth

Pola

r R

egio

n

Dry

gals

ki is

a P

re-N

ecta

rian

cra

ter

(149

km

dia

met

er).

It h

asa

stro

ng c

entr

al p

eak

and

a w

ell-

defin

ed r

im, a

ltho

ugh

it h

asbe

en d

egra

ded

by d

epos

its

from

sub

sequ

ent

impa

cts.

It

has

been

cov

ered

wit

h ej

ecta

fro

m t

he B

ailly

Bas

in (

LO4-

193H

2,LO

4-17

9H3)

, who

se m

ain

ring

pas

ses

just

to th

e no

rthe

ast o

fLe

Gen

til.

Stri

atio

ns n

ear

Dry

gals

ki t

hat

com

e fr

om t

heno

rthe

ast

are

radi

al t

o B

ailly

. D

ryga

lski

has

im

pact

edbr

oade

r ri

dges

and

val

leys

at

righ

t an

gles

to

thos

e fr

omB

ailly

; th

ey a

re r

adia

l to

the

Sou

th P

ole–

Aik

en B

asin

.D

ryga

lski

is o

n th

e to

pogr

aphi

c ri

ng o

f tha

t bas

in.

LO4-

193H

1Su

n El

evat

ion:

9.3

°A

ltit

ude:

351

9.21

km

29

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Hau

sen

is a

wel

l-fo

rmed

cra

ter

wit

h a

rugg

ed c

entr

al p

eak,

asu

gges

tion

of

an i

nner

rin

g, a

nd a

wel

l-pr

eser

ved

ejec

tabl

anke

t. I

t is

the

lar

gest

cra

ter

(167

km

) of

eit

her

the

Erat

osth

enia

n Pe

riod

or

the

Cop

erni

can

Peri

od. O

nly

Hum

-bo

ldt

(207

km

, Lat

e Im

bria

n) is

larg

er a

mon

g im

pact

eve

nts

afte

r O

rien

tale

. T

he e

ject

a of

Hau

sen,

whi

ch o

verl

ies

the

mai

n ri

ng a

nd fl

oor

of th

e B

ailly

Bas

in, s

how

s a

herr

ingb

one

patt

ern,

esp

ecia

lly t

o th

e no

rth.

Thi

s pa

tter

n re

sult

s fr

omla

tera

l ve

loci

ty i

mpa

rted

to

the

edge

s of

a t

ongu

e of

eje

cta

duri

ng la

ndin

g. O

utsi

de o

f the

Hau

sen

ejec

ta, t

o th

e no

rth

ofB

ailly

, is

a he

avy

clus

ter

of O

rien

tale

sec

onda

ries

that

hel

p to

esta

blis

h th

e se

quen

ce a

s fir

st B

ailly

, th

en O

rien

tale

, th

enH

ause

n.

LO4-

193H

2Su

n El

evat

ion:

9.3

°A

ltit

ude:

351

9.21

km

29

5So

uth

Pola

r R

egio

n

Thi

s ar

ea i

s co

vere

d w

ith

the

scul

pted

rid

ges

and

valle

ys(s

uch

as V

allis

Baa

de)

of t

he I

nner

Hev

eliu

s Fo

rmat

ion,

the

heav

y ej

ecta

bla

nket

fro

m t

he O

rien

tale

Bas

in. M

any

of t

hecr

ater

s su

ch a

s C

atal

an a

re c

ause

d by

obj

ects

thr

own

high

from

Ori

enta

le t

hat

subs

eque

ntly

fel

l on

the

fre

sh e

ject

abl

anke

t of O

rien

tale

(th

e ej

ecta

bla

nket

follo

wed

a fa

ster

pat

hat

a lo

w in

clin

atio

n to

the

surf

ace)

. The

flat

ness

of t

he te

rrai

nin

the

low

er l

eft

of t

his

phot

o re

sult

s fr

om i

ts f

orm

atio

n as

the

floor

of

the

anci

ent

Men

del-

Ryd

berg

Bas

in, w

hich

con

-ti

nues

wes

t in

to t

he f

ar s

ide.

The

mai

n ri

ng o

f th

is b

asin

is

nort

h of

Gut

hnic

k an

d ea

st o

f Yak

ovki

n; th

e ea

ster

n se

ctor

of

this

rin

g ca

n be

see

n in

LO

4-17

9H3.

29

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

193H

3Su

n El

evat

ion:

9.3

Alt

itud

e: 3

519.

21 k

m

Hea

vy c

lust

ers

of O

rien

tale

sec

onda

ry c

rate

rs d

omin

ate

this

area

. The

mai

n ri

ng o

f the

Med

el-R

ydbe

rg B

asin

can

be

seen

ente

ring

thi

s ph

oto

from

the

upp

er l

eft

corn

er,

curl

ing

arou

nd P

ingr

e, a

nd i

nter

sect

ing

the

mai

n ri

ng o

f th

e B

ailly

Bas

in (

the

Bai

lly B

asin

has

obl

iter

ated

the

old

er r

ing)

.A

ltho

ugh

the

ring

s of

the

Men

del-

Ryd

berg

Bas

in a

re m

uch

degr

aded

, th

e de

pres

sion

of

its

floor

is

very

cle

ar i

n th

eC

lem

enti

ne e

leva

tion

dat

a.

LO4-

179H

3Su

n El

evat

ion:

7.1

°A

ltit

ude:

359

1.83

km

29

7So

uth

Pola

r R

egio

n

As

is t

ypic

al i

n th

e ph

otos

of

this

mis

sion

tha

t co

ver

the

Sout

h Po

le,

not

only

the

pol

e it

self

but

muc

h of

the

sur

-ro

undi

ng t

erri

tory

is

in s

hado

w,

som

e of

it

in p

erm

anen

tsh

adow

, exp

osed

to th

e co

ld o

f dee

p sp

ace

wit

hout

hea

t fro

mth

e su

n. T

his

is o

ne o

f the

bet

ter

view

s of

Mal

aper

t, sh

owin

git

to b

e of

a c

haot

ic fo

rm. I

t is

not c

lear

whe

ther

it is

a c

rate

rw

hose

wal

ls w

ere

push

ed a

side

by

othe

r im

pact

s or

sim

ply

ach

ance

arr

ange

men

t of d

ebri

s fr

om m

ulti

ple

impa

cts.

LO4-

166H

1Su

n El

evat

ion:

7.0

°A

ltit

ude:

359

2.60

km

29

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

Thi

s is

the

mos

t co

mpl

ete

view

of

Bai

lly, j

ust

big

enou

gh a

t30

0 km

to fo

rm a

mul

ti-r

inge

d ba

sin.

An

oute

r ri

ng r

uns

near

the

righ

t ed

ge o

f thi

s ph

oto

and

into

Le

Gen

til;

sect

ors

of a

nin

ner

ring

are

als

o vi

sibl

e. S

econ

dari

es fr

om O

rien

tale

dom

i-na

te t

he r

egio

n, b

ut e

arlie

r cr

ater

s ha

ve b

een

cove

red

wit

h a

mor

e un

ifor

m p

ulve

rize

d m

ater

ial,

prob

ably

als

o pa

rt o

fO

rien

tale

eje

cta.

LO4-

166H

2Su

n El

evat

ion:

7.0

°A

ltit

ude:

359

2.60

km

29

9So

uth

Pola

r R

egio

n

The

cha

ins

of s

econ

dari

es a

re r

adia

l to

Ori

enta

le. T

he h

eavy

ejec

ta b

lank

et s

eem

s to

end

at

a ri

dge

that

is

runn

ing

from

the

east

ern

edge

of P

hocy

lides

dow

n to

the

nort

hern

edg

e of

Zuc

chiu

s. T

his

is a

sec

tor

of t

he m

ain

ring

of

the

Schi

ller-

Zuc

chiu

s B

asin

. Pl

ains

uni

ts h

ave

been

for

med

by

the

pow

dery

out

er H

evel

ius

Form

atio

n of

Ori

enta

le c

over

ing

flat

crat

er fl

oors

suc

h as

tho

se o

f Ph

ocyl

ides

, W

arge

ntin

, an

dN

asm

yth

and

the

floor

of

the

Schi

ller-

Zuc

chiu

s B

asin

(L

O4-

154H

3).

LO4-

166H

3Su

n El

evat

ion:

7.0

°A

ltit

ude:

359

2.60

km

30

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

80t

h so

uthe

rn p

aral

lel

(the

80°

S li

ne o

f la

titu

de)

issh

own

here

as

a da

shed

arc

. In

thre

e-di

men

sion

al g

eom

etry

,a

para

llel i

s a

circ

le, b

ut in

thi

s ph

otog

raph

, tak

en w

hen

the

spac

ecra

ft w

as a

t 72.

07°S

, the

cir

cle

is fo

resh

orte

ned.

Cra

ters

near

the

Sou

th P

ole,

lik

e th

ose

at t

he N

orth

Pol

e, a

re o

ften

nam

ed a

fter

exp

lore

rs o

f th

e po

les

of E

arth

. Rob

ert

Falc

onSc

ott,

who

se c

rate

r is

sho

wn

part

icul

arly

wel

l in

this

pho

to,

led

the

seco

nd p

arty

to

reac

h th

e So

uth

Pole

of

Eart

h in

Janu

ary

1912

, 1 m

onth

aft

er A

mun

dsen

had

bee

n th

ere.

Sco

ttdi

ed a

long

wit

h tw

o of

his

men

on

the

retu

rn fr

om th

e Po

le.

LO4-

154H

1Su

n El

evat

ion:

10.

8°A

ltit

ude:

361

3.43

km

30

1So

uth

Pola

r R

egio

n

Thi

s ar

ea h

as n

ot o

nly

been

bom

bard

ed w

ith

prim

ary

im-

pact

ors

duri

ng th

e fo

rmat

ion

of th

e M

oon

and

afte

r, b

ut h

asbe

en

subj

ecte

d to

bu

rial

w

ith

ejec

ta

from

th

e So

uth

Pole

–Aik

en B

asin

, th

e B

ailly

Bas

in,

and

seco

ndar

y cr

ater

spr

obab

ly f

rom

the

Ori

enta

le B

asin

. Kla

prot

h, y

oung

eno

ugh

to h

ave

a re

ason

ably

inta

ct r

im in

its

nort

heas

tern

sec

tor,

has

had

othe

r se

ctor

s of

its

rim

impa

cted

in tu

rn b

y C

asat

us a

ndtw

o ot

her

crat

ers.

How

ever

, its

floo

r se

ems

youn

g, fl

at, a

ndre

lati

vely

sm

ooth

. Per

haps

tec

toni

c fo

rces

hav

e le

vele

d pu

l-ve

rize

d ej

ecta

in th

at a

rea.

Wha

teve

r ha

ppen

ed to

sm

ooth

the

floor

hap

pene

d lo

ng a

go. U

nder

hig

h m

agni

ficat

ion,

a h

eavy

pepp

erin

g of

sm

alle

r (2

km

and

less

) cr

ater

s ca

n be

see

n.

30

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

154H

2Su

n El

evat

ion:

10.

8°A

ltit

ude:

361

3.43

km

An

oute

r ri

ng o

f th

e Sc

hille

r-Z

ucch

ius

Bas

in c

an b

e se

enru

nnin

g ju

st e

ast

of S

chill

er, s

outh

to

the

edge

of

Ros

t, an

dar

ound

ben

eath

Zuc

chiu

s. W

ithi

n th

is o

uter

rin

g is

the

mai

nri

ng, i

ncom

plet

e in

its

nort

hern

sec

tor.

Sec

onda

ry c

hain

s on

the

floor

of

this

bas

in a

re f

rom

Ori

enta

le t

o th

e no

rthw

est.

Schi

ller

was

pro

babl

y fo

rmed

by

the

sim

ulta

neou

s ar

riva

l of

two

or m

ore

prim

ary

impa

ctor

s co

min

g in

at a

ver

y lo

w a

ngle

to th

e su

rfac

e.

LO4-

154H

3Su

n El

evat

ion:

10.

8°A

ltit

ude:

361

3.43

km

30

3So

uth

Pola

r R

egio

n

Smal

ler

crat

ers,

less

than

30

km in

siz

e, a

re r

elat

ivel

y de

ep. I

fth

ey a

re n

ear

a po

le th

eir

floor

s ar

e lik

ely

to b

e in

per

man

ent

shad

ow.

Thi

s is

esp

ecia

lly t

rue

if t

hey

are

on t

he n

orth

ern

part

of

the

floor

s of

lar

ger

crat

ers

who

se r

ims

then

hel

p to

shad

e th

em.

LO4-

130H

1Su

n El

evat

ion:

8.7

°A

ltit

ude:

357

4.83

km

30

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

anc

ient

, ove

r-cr

ater

ed t

erra

in o

f thi

s ar

ea is

inte

rrup

ted

by E

rato

sthe

nian

Cra

ter

Mor

etus

, wit

h a

wel

l-fo

rmed

cen

tral

peak

and

an

inta

ct e

ject

a pa

tter

n.

LO4-

130H

2Su

n El

evat

ion:

8.7

°A

ltit

ude:

357

4.83

km

30

5So

uth

Pola

r R

egio

n

The

sm

ooth

ing

of t

he t

erra

in n

orth

and

sou

th o

f C

lavi

us i

spr

obab

ly c

ause

d by

eit

her

its

ejec

ta b

lank

et o

r th

e sh

ock

ofit

s im

pact

on

a pr

eexi

stin

g ac

cum

ulat

ion

of e

ject

a fr

om o

ther

impa

cts.

At

225

km, i

t is

abo

ut a

s bi

g as

a c

rate

r ca

n be

; it

isin

the

tran

siti

on r

ange

bet

wee

n cr

ater

s an

d ba

sins

. The

ori

gi-

nal c

entr

al p

eak

may

hav

e be

en la

rger

tha

n it

is n

ow. I

t m

ayha

ve b

een

larg

ely

buri

ed b

y ej

ecta

. R

ays

from

Cop

erni

can

crat

er T

ycho

to

the

nort

h ha

ve a

lso

land

ed i

n th

is r

egio

n.T

his

area

may

con

tain

sec

onda

ries

fro

m b

oth

the

Ori

enta

lean

d Im

briu

m B

asin

s.

30

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

130H

3Su

n El

evat

ion:

8.7

°A

ltit

ude:

357

4.83

km

Slum

ps f

rom

the

rim

of

Cla

vius

to

its

floor

are

abo

ut 1

5 to

20

km

in

wid

th. T

his

size

is

typi

cal

of t

he s

lum

ps i

n cr

ater

wal

ls,

inde

pend

ent

of t

he d

iam

eter

of

the

crat

er.

Smal

ler

crat

ers

tend

to h

ave

slum

ps in

the

sam

e ab

solu

te s

ize

rang

e.

LO4-

118H

3Su

n El

evat

ion:

7.8

°A

ltit

ude:

355

4.96

km

30

7So

uth

Pola

r R

egio

n

Euge

ne M

. Sh

oem

aker

, th

e fo

unde

r of

the

USG

S A

stro

-ge

olog

y B

ranc

h, h

as b

een

a m

ajor

lead

er in

rev

ealin

g th

e im

-pa

ct o

rigi

n of

mos

t Moo

n cr

ater

s an

d so

me

on E

arth

. Gen

e’s

succ

essf

ul c

aree

r w

as e

nded

by

a fa

tal

auto

mob

ile a

ccid

ent

as h

e so

ught

to in

vest

igat

e ye

t ano

ther

cra

ter

in A

ustr

alia

. At

the

end

of i

ts s

ucce

ssfu

l m

issi

on,

the

spac

ecra

ft L

unar

Pros

pect

or w

as c

rash

ed i

nto

this

per

man

entl

y co

ld c

rate

rflo

or (

now

nam

ed a

fter

Gen

e) in

an

atte

mpt

to

dete

ct w

ater

in t

he c

rash

plu

me.

The

spa

cecr

aft

carr

ied

a vi

al c

onta

inin

ghi

s as

hes,

and

Gen

e be

cam

e th

e fir

st p

erso

n to

be

inte

rred

beyo

nd E

arth

.

LO4-

106H

1Su

n El

evat

ion:

9.1

°A

ltit

ude:

353

4.50

km

30

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

re i

s a

tran

siti

on i

n th

is a

rea,

esp

ecia

lly t

o th

e ea

st,

betw

een

heav

y cr

ater

ing

in c

haot

ic d

ebri

s an

d cr

ater

ing

in a

rela

tive

ly fl

at s

urfa

ce. T

his

coul

d m

ark

the

tran

siti

on b

etw

een

the

inne

r he

avy

ejec

ta fr

om th

e So

uth

Pole

–Aik

en B

asin

and

the

oute

r pl

ains

-for

min

g an

d se

cond

ary

field

of

that

bas

in.

To

the

wes

t, t

he e

quiv

alen

t ar

ea h

as b

een

tran

sfor

med

by

smal

ler

basi

ns f

rom

im

pact

s th

at a

rriv

ed lo

ng a

fter

the

for

-m

atio

n of

the

Sou

th P

ole–

Aik

en B

asin

, but

to

the

east

the

rear

e fe

wer

suc

h ba

sins

.

LO4-

106H

2Su

n El

evat

ion:

9.1

°A

ltit

ude:

353

4.50

km

30

9So

uth

Pola

r R

egio

n

Thi

s ar

ea i

s ab

out

one

basi

n di

amet

er f

rom

Nub

ium

and

Nec

tari

s, a

bout

1.5

dia

met

ers

from

Im

briu

m,

and

abou

t 0.

5 di

amet

er f

rom

the

Sou

th P

ole–

Aik

en B

asin

. Thi

s fie

ld o

ffr

esh

30-k

m s

econ

dary

cra

ters

is

radi

al t

o Im

briu

m.

Som

egr

oups

of

smal

l (2

-km

) se

cond

arie

s ar

e th

ough

t to

com

efr

om t

he N

ecta

ris

Bas

in f

ar t

o th

e no

rthe

ast.

Stri

atio

ns n

ear

the

left

edg

e of

this

pho

to a

re r

adia

l to

Cla

vius

.

31

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

106H

3Su

n El

evat

ion:

9.1

°A

ltit

ude:

353

4.50

km

Thi

s fla

t ar

ea is

abo

ut a

s fa

r as

one

can

get

fro

m b

asin

s an

dla

rge

crat

ers

on t

he n

ear

side

. St

ill,

ther

e ar

e m

any

crat

ercl

uste

rs o

f va

riou

s si

zes

and

degr

ees

of d

egra

dati

on t

hat

are

prob

ably

sec

onda

ries

fro

m r

emot

e ba

sins

. A b

asin

has

bee

npr

opos

ed t

o be

nor

th o

f M

utus

, bu

t C

lem

enti

ne e

leva

tion

data

sho

w t

hat

area

to

be r

elat

ivel

y hi

gh. T

he a

rea

may

be

crus

t tha

t has

esc

aped

maj

or im

pact

s by

cha

nce.

LO4-

094H

3Su

n El

evat

ion:

9.8

°A

ltit

ude:

351

6.92

km

31

1So

uth

Pola

r R

egio

n

Thi

s is

the

sun

nies

t vi

ew o

f cr

ater

Am

unds

en f

rom

Lun

arO

rbit

er M

issi

on 4

. Roa

ld A

mun

dsen

led

the

first

exp

edit

ion

to r

each

the

Sou

th P

ole

of E

arth

, su

ccee

ding

in

Dec

embe

r19

10. H

e re

turn

ed s

afel

y an

d co

ntin

ued

expl

orat

ions

of b

oth

pola

r re

gion

s. T

he c

lust

er o

f fr

esh-

look

ing

crat

ers

in t

he 1

0-to

30-

km s

ize

rang

e ar

e pr

obab

ly s

econ

dari

es fr

om Im

briu

m,

a fu

ll tw

o di

amet

ers

away

from

its

mai

n ri

ng. T

his

is fu

rthe

rth

an s

econ

dari

es a

re u

sual

ly t

hrow

n, b

ut b

ecau

se o

f the

siz

eof

Im

briu

m,

the

curv

atur

e of

the

Moo

n m

ay e

xten

d th

eir

trav

el. T

o pu

t it a

noth

er w

ay, t

he e

ject

ion

velo

city

was

pro

ba-

bly

clos

er to

esc

ape

velo

city

.

31

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

082H

1Su

n El

evat

ion:

8.7

°A

ltit

ude:

350

2.94

km

The

pro

min

ent c

hain

s of

cra

ters

her

e ar

e ra

dial

to I

mbr

ium

.Sc

hom

berg

er h

as e

scap

ed s

uch

impa

cts;

in fa

ct, i

ts e

ject

a ha

sfa

llen

on s

ome

seco

ndar

y cr

ater

s. I

t has

bee

n as

sign

ed to

the

Late

Imbr

ian

Epoc

h.

LO4-

082H

2Su

n El

evat

ion:

8.7

°A

ltit

ude:

350

2.94

km

31

3So

uth

Pola

r R

egio

n

Vla

cq, N

earc

h, a

nd M

utus

are

bel

ieve

d to

be

Pre-

Nec

tari

an.

A c

hain

of s

econ

dary

cra

ters

rad

ial t

o th

e N

ecta

ris

Bas

in c

anbe

see

n on

the

nor

thw

est

rim

of N

earc

h. O

ther

cra

ter

chai

nsbe

twee

n T

anne

rus

and

Nea

rch

are

radi

al to

Ori

enta

le.

LO4-

082H

3Su

n El

evat

ion:

8.7

°A

ltit

ude:

350

2.94

km

31

4Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

The

lon

g ch

ain

of s

mal

l cr

ater

s in

the

low

er r

ight

of

this

phot

o is

rad

ial

to t

he N

ecta

ris

Bas

in. S

imila

r ch

ains

can

be

seen

nor

th o

f Bie

la.

LO4-

070H

3Su

n El

evat

ion:

9.7

°A

ltit

ude:

349

6.53

km

31

5So

uth

Pola

r R

egio

n

Nob

ile is

wel

l illu

min

ated

in th

is p

hoto

, but

its

floor

rem

ains

in s

hado

w.

Um

bert

o N

obile

was

an

aero

naut

ical

eng

inee

ran

d an

exp

lore

r of

the

Art

ic. H

e an

d R

oald

Am

unds

en w

ere

the

first

to fl

y ov

er th

e N

orth

Pol

e of

Ear

th (

1926

); th

ey u

sed

a di

rigi

ble.

Tw

o ye

ars

late

r, o

n an

othe

r vo

yage

of

ex-

plor

atio

n, N

obil

e cr

ashe

d in

a d

irig

ible

on

the

ice

near

Spit

sber

gen.

Am

unds

en d

ied

in a

n at

tem

pt t

o fly

in

and

resc

ue N

obile

, who

sur

vive

d.

31

6Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

058H

1Su

n El

evat

ion:

8.5

°A

ltit

ude:

349

3.64

Bous

sing

ault

is n

ot a

nes

ted

crat

er p

rodu

ced

by im

pact

into

ala

yere

d ta

rget

: a s

ubse

quen

t im

pact

has

hit

its

floor

to c

reat

eth

is u

nusu

al t

opog

raph

y. T

he r

elat

ive

ages

of

crat

ers

in t

his

area

can

be

infe

rred

from

the

shar

pnes

s of

thei

r fe

atur

es a

ndde

gree

of s

ubse

quen

t cra

teri

ng. A

ll th

e na

med

cra

ters

in th

isph

oto

are

assi

gned

to th

e Pr

e-N

ecta

rian

Per

iod.

LO4-

058H

2Su

n El

evat

ion:

8.5

°A

ltit

ude:

349

3.64

km

31

7So

uth

Pola

r R

egio

n

Nea

r th

e to

p of

thi

s ph

oto

ther

e ar

e st

riat

ion

s ra

dial

to

Nec

tari

s, to

the

nort

hwes

t. C

rate

r ch

ains

on

the

righ

t sid

e of

the

phot

o ar

e ra

dial

to

the

Fecu

ndit

atis

Bas

in t

o th

e no

rth,

but

they

see

m t

oo f

resh

to

have

com

e fr

om a

bas

in t

hat

old.

Per

haps

the

y ca

me

from

the

Cri

sium

Bas

in,

beyo

ndFe

cund

itat

is.

31

8Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

058H

3Su

n El

evat

ion:

8.5

°A

ltit

ude:

349

3.64

km

Thi

s is

an

apol

une

phot

o, t

aken

at

the

end

of t

he m

issi

on t

o fil

l in

cov

erag

eth

at w

as m

isse

d at

the

beg

inni

ng o

f th

e m

issi

on d

ue t

o th

e th

erm

al d

oor

prob

lem

. Con

sequ

entl

y, t

he s

unlig

ht c

omes

fro

m t

he w

est.

Cra

ter

chai

ns t

hat

are

alig

ned

wit

h V

alli

s R

heit

a co

me

from

Nec

tari

s. T

hose

tha

t ar

e m

ore

31

9So

uth

Pola

r R

egio

n

LO4-

184H

3Su

n El

evat

ion:

6.9

°A

ltit

ude:

579

0.16

km

alig

ned

wit

h th

e no

rth-

sout

h di

rect

ion

are

radi

al t

o th

e Fe

cund

itat

is a

ndC

risi

um B

asin

s. T

he p

lain

s no

rth

of B

iela

are

cov

ered

wit

h N

ecta

ris

ejec

ta.

Pont

ecou

lant

is o

f the

Nec

tari

an P

erio

d.

Phot

o LO

4-00

5 w

as t

aken

ear

ly i

n th

e m

issi

on,

befo

re t

hepr

oble

m w

ith

the

ther

mal

doo

r oc

curr

ed. T

his

phot

o sp

ans

the

90°

east

mer

idia

n, t

he b

ound

ary

betw

een

the

near

sid

ean

d fa

r si

de. T

race

s of

a v

ery

old,

larg

e (2

00-k

m)

crat

er c

anbe

see

n in

the

upp

er r

ight

of

this

pho

to,

lyin

g be

neat

hG

answ

indt

and

Ide

l’son

. Its

deg

rade

d ri

m i

s ta

ngen

t to

the

nort

h ri

m o

f Gan

swin

dt a

nd r

uns

abov

e th

e ed

ge o

f the

pho

toar

ound

to H

eder

vari

.

32

0Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

005H

1Su

n El

evat

ion:

8.9

°A

ltit

ude:

349

7.58

km

LO4-

005H

2Su

n El

evat

ion:

8.9

°A

ltit

ude:

349

7.58

km

32

1So

uth

Pola

r R

egio

n

The

hea

vy r

idge

s an

d va

lleys

com

ing

from

the

nor

thea

st,

pass

ing

wes

t of

Wex

ler

and

east

of

Neu

may

er, a

re r

adia

l to

the

Aus

tral

e Ba

sin.

The

rid

ges

and

valle

ys th

at c

ross

them

are

radi

al t

o th

e Sc

hrod

inge

r B

asin

on

the

far

side

(se

e Fi

gure

12.3

). N

eum

ayer

is

Nec

tari

an.

Hal

e ap

pear

s to

be

muc

hyo

unge

r, p

roba

bly

Erat

osth

enia

n.

The

cen

ter

of t

he a

ncie

nt A

ustr

ale

Bas

in i

s ea

st o

f Ly

ot a

ndno

rth

of J

eans

. The

floo

r of

thi

s ba

sin

near

ly, b

ut n

ot q

uite

,flo

oded

wit

h m

are

lava

. Lar

ge c

rate

rs s

uch

as L

yot a

nd L

amb

(LO

4-00

9H2

in th

e Ea

ster

n B

asin

Reg

ion)

see

m to

hav

e st

im-

ulat

ed t

he fl

ow. T

he ja

gged

dag

ger

in t

he lo

wer

rig

ht c

orne

rof

the

pho

to i

s th

e ti

p of

Val

lis S

chro

ding

er, a

310

-km

-lon

gra

dial

fra

ctur

e fr

om t

he f

ar s

ide

Schr

odin

ger

Bas

in (

see

Figu

re 1

2.3)

.

32

2Lu

na

r O

rbiter

Photo

gra

phic

Atla

s

LO4-

005H

3Su

n El

evat

ion:

8.9

°A

ltit

ude:

349

7.58

km

Latin Words in Names of Features

Catena: Bowl, a chain of craters.Dorsum: Backbone, a ridge, often wrinkled, in the surface of a mare.Lacus: Hollow, a small depression filled with lava flows.Mare: Sea, dark, smooth plains formed by lava flows in a large

depression.Mons, Montes: Mount, mountains, a peak or range of mountains.Palus: Swamp, a small area with shallow lava flows.Planitia: Plain, a low flat area.Promontorium: Promontory, a highland peninsula extending into a

mare.Rima: Crack, leak, a narrow, long channel that may be sinuous (a

sign of meandering lava flow), straight, or in an arc (signs of afault).

Rupes: Cliff, a long abrupt change in elevation; a cliff along a verti-cal fault or an edge of a lava flow.

Sinus: Bay, an extension of a mare.Vallis: Valley, a wide, long depression.

Age Ranges on the Moon (Oldest First)

Pre-Nectarian Period: The age range between the hardening of the crust and the impact event that formed the Nectaris Basin.

Nectarian Period: The age range between the formation of theNectaris Basin and the Imbrium Basin.

Early Imbrian Epoch: The age range from the formation of theImbrium Basin through that of the Orientale Basin.

Late Imbrian Epoch: The age range from the formation of theOrientale Basin through the most voluminous lava flows.

Eratosthenian Period: The age range of declining heavy lava flowand declining rate of impact. This period includes the formationof rayless post-mare craters like Eratosthenes.

Copernican Period: This age range extends from the time of forma-tion of the oldest bright-rayed craters to the present. Copernicus,with very bright rays, is the typical young crater of this period.Since the rays of craters fade with time, craters with dimmer raysare assigned older ages in this period.

General Terms

Albedo: The inherent brightness of a surface.

Apolune: The point on a lunar orbit farthest from the surface of theMoon.

Basin: A large crater-like depression containing one or more ringsin addition to a rim. Also “multi-ringed basin.”

Crater: A compact depression. Nearly all craters on the Moon arecaused by impact; when fresh, impact craters usually are nearlycircular and have raised rims.

Crust: The upper layer of rock, composed of minerals that have sep-arated from a melt and risen because of their low density.

Ejecta: Material thrown out from a transient crater as a result of theenergy released by an impact.

Limb: An edge of a celestial body like the Moon, as viewed. KREEP: An acronym representing potassium (chemical symbol K),

Rare Earth Elements, and Phosphor. These elements are late tocrystallize from a cooling melt.

Main ring: The highest ring of a basin. Also called the rim of thebasin or the topographic ring.

Mantle: The layer of rock below the crust, composed of mineralsthat have separated from a melt and fallen because of their highdensity.

Mascon: A concentrated mass that affects the gravity field of theMoon. Mascons are associated with pipes of high-density mantlematerial that flooded maria.

Perilune: The point on a lunar orbit closest to the surface of theMoon.

Ring: A circular ridge that is formed along with a basin. Internalrings are inside the main ring and external rings are outside themain ring.

Secondary crater: A crater formed by the impact of material ejectedfrom another (primary) crater or basin.

Theia: The small planet that impacted Earth to form the Moon,named for a Greek goddess whose daughter was said to be Selene,the goddess of the Moon.

Topographic rim: The highest ring around a crater. Also called themain ring if the crater exhibits multiple rings and troughs (amulti-ringed basin).

Topography: The shape of a surface.Transient crater: The material that is fractured, melted, and vapor-

ized by a hypervelocity impact before further dynamic processesredistribute the material as ejecta, secondary impactors, and soon.

Trough: A shallow linear or curved depression, especially a circularvalley between rings of a basin.

Glossary

32

3G

loss

ary

Bowker, 1971: D.E. Bowker and J.K. Hughes, Lunar OrbiterPhotographic Atlas of the Moon, NASA SP 206.

Bussey, 2004: Ben Bussey and Paul D. Spudis, The Clementine Atlasof the Moon, Cambridge University Press, Cambridge.

Byrne, 2002a: C.J. Byrne, Automated Cosmetic Improvements ofMosaics from the Lunar Orbiter, Lunar and Planetary ScienceConference (LPSC) 33, #1099.

Byrne, 2002b: C.J. Byrne, A New Moon: Improved Lunar OrbiterMosaics, The Moon Beyond 2002: Next Steps in Lunar Scienceand Exploration, p. 7, LPI Contribution No. 1128, Lunar andPlanetary Institute, Houston.

Byrne, 2003: C.J. Byrne, Proposed High-Level Regional Focal Pointsfor Lunar Geography, LPSC 34, #1517.

Byrne, 2004: C.J. Byrne, Evidence for Three Basins beneath OceanusProcellarum, Lunar and Planetary Science Conference (LPSC) 35,#1103.

De Hon, 1979: R.E. De Hon, Thickness of the Western MareBasalts, Lunar and Planetary Science Conference (LPSC) 10, pp. 2935–2955.

Gaddis, 1997: L. Gaddis, et al., An Overview of the IntegratedSoftware for Imaging Spectrometers (ISIS), Lunar and PlanetaryScience Conference (LPSC) 28, #387.

Gaddis, 2001: L. Gaddis, et al., Cartographic Processing of DigitalLunar Orbiter Data, LPS 32, Abstract #1892, Lunar and PlanetaryInstitute, Houston (CDROM).

Gasnault, 2002: O. Gasnault, W.C. Feldman, C. d’Uston, D.J.Lawrence, S. Maurice, S.D. Chevral, P.C. Pinet, R.C. Elphic, I.Genetay, and K.R. Moore, JGR 107 (E10).

Gault, 1978: D.E. Gault and J.A. Wedekind, Experimental Studies ofOblique Impact, Lunar and Planetary Science Conference (LPSC)9, v. 3, pp. 3843–3875.

Gillis, 2002: J. Gillis (ed.), Digital Lunar Orbiter Photographic Atlasof the Moon, www.lpi.usra.edu/research/lunarorbiter, Lunar andPlanetary Institute, Houston.

Gonzalez, 2002: Rafael C. Gonzalez and Richard E. Woods, DigitalImage Processing, Second Edition, Addison Wesley, Reading.

Greeley, 1976: R. Greeley and M.H. Carr, Editors, A Geological Basisfor the Exploration of the Planets, NASA Report SP-417.

Hawke, 2004: B.R. Hawke et al., The Origin of Lunar Crater Rays,LPSC 35, Abstract #1477, Lunar and Planetary Institiute(CDROM).

McEwen, 1994: A. McEwen, P. Davis, and A. Howington-Kraus,Evidence for a Pre-Nectarian Impact Basin in NorthwesternOceanus Procellarum, Lunar and Planetary Science Conference(LPSC) 25, Abstract # 869, Lunar and Planetary Institute,Houston.

Quaide, 1968: W.L. Quaide and V.R. Oberbeck, Thickness determi-nations of the lunar surface layer from lunar impact craters,Journal of Geophysics Research 73:5247–5270.

Schultz, 1972: P.H. Schultz, Moon Morphology, University of TexasPress.

Spudis, 1993: P.D. Spudis, The Geology of Multi-Ring Impact Basins:The Moon and Other Planets, Cambridge University Press,Cambridge.

Spudis, 1996: P.D. Spudis, The Once and Future Moon, SmithsonianInstitution Press, Washington, DC.

Stevens, 1999: R. Stevens, Visual Basic Graphics Programming,Second Edition, Wiley, New York.

Whitaker, 1999: E.A. Whitaker, Mapping and Naming the Moon,Cambridge University Press, Cambridge.

Whitaker, 1970; E.A. Whitaker et al., Atlas and Gazetteer of theNear Side of the Moon, NASA SP-241.

Wilhelms, 1987: D.E. Wilhelms et al., The Geologic History of theMoon, USGS Professional Paper 1348, US Government PrintingOffice, Washington, DC.

Wilhelms, 1993: D.E. Wilhelms, To a Rocky Moon, The University ofArizona Press.

References

32

4Lu

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r O

rbiter

Photo

gra

phic

Atla

s

32

5G

ener

al

Ind

ex

Basins (continued)—Humorum, 55, 63, 68, 72, 76, 77,

79, 82 (see Vitello Formation) —Imbrium, 100–102, 125–158 (see

Fra Mauro and Alps Formations)—Lavoissier-Mairan, 101, 104, 118—Mendel-Rydberg, 296, 297—Nectaris, 155, 156, 164–194 (see

Janssen Formation)—Northern Serenitatis, 201, 207, 217—Nubium, 55, 77–79, 82, 87, 89, 93,

94—Orientale, 13–16, 20, 24, 34, 36,

53, 54 (see Hevelius Formation)—Reiner-Letronne, 102—Schiller-Zucchius, 57, 60, 300, 303—Schrodinger, 92, 292, 322—Serenitatis, 200, 201, 204–207,

209–211, 214–217, 220–225—Smythii, 244, 245, 251, 252, 256,

257, 262—South Pole-Aiken, 245, 260, 291,

292, 309—Tranquillitatis, 155, 190, 201,

219–220, 224, 231

Cataclysm, 8Censorinus Highlands, 228, 231Compact Disc, 11Crustal depth, 8

Deep Space Network, 7

Formations—Alpes, 154, 206, 210, 212—Cayley, 156, 169, 170, 213—Descartes, 156, 169, 170—Fra Mauro, 90, 100–102, 131, 151—Hevelius, 15, 42, 46, 49—Inner Hevelius, 15, 18, 25, 28, 32,

38, 42—Janssen, 171, 180, 186, 192—Maunder, 16, 17, 21, 23—Montes Rook, 18, 21—Outer Hevelius, 15, 19, 26, 34, 42,

48

Formations (continued)—Vitello, 66, 67

Gravity field, 9

Highlands, 8

Jet Propulsion Laboratory, 7

Kant Plateau, 175Kodak BimatTM process, 7Kuiper Belt, 136

Landmarks, 9—Humorum Basin, 9, 10—Imbrium Basin, 9, 10—Nectaris Basin, 9, 10—North Pole, 9, 10—Orientale Basin, 9, 10—Serenitiatis Basin, 9, 10—Smythii Basin, 9, 10—South Pole, 9, 10Langley Research Center, 7Luna missions—Luna 05, 85, 137—Luna 07, 120—Luna 15, 246, 249—Luna 16, 199, 240, 249—Luna 18, 240, 249—Luna 20, 240, 249—Luna 21, 224, 225—Luna 24, 246Lunar Orbiter—Cameras, 5—Famelet, 7 —Film, 5—Ground Recording Equipment, 7—High-resolution camera, 5—Image motion compensation, 5—Medium-resolution camera, 5—Mission 2—Mission 4, 5—Order of photos, 6, 11—Scanning artifacts, 7

Lunar Orbiter (continued)—Subframes, 7, 11—Venetian blind effect, 7

Magma ocean, 8Maps, large scale, 2–4Marius Hills, 115, 120 Mascons, 9

North Pole, 269, 273, 277, 281, 285,289

Origin of the Moon, 8

Ranger missions—Ranger 7, 84—Ranger 8, 219—Ranger 9, 98Regional Planetary Image Facilities, 7Regions, 2–4—Eastern Basins Region, 10, 244—Humorum Basin Region, 10, 55—Imbrium Basin Region, 10, 100—Nectaris Basin Region, 10, 155—North Polar Region, 10, 263—Orientale Basin Region, 10, 13—Serenitatis Basin Region, 10, 200—South Polar Region, 10, 291

Shoemaker-Levy 9, 169South Pole, 298, 301, 304, 308, 312,

316, 320Surveyor missions—Surveyor 1, 70—Surveyor 3, 85, 137—Surveyor 4, 99, 202—Surveyor 5, 219—Surveyor 6, 99, 202—Surveyor 7, 86Synchronization of the Moon’s

orbit, 8

Theia, 301

Age periods and epochs, 10—Copernican Period, 10, 323—Early Imbrian Epoch, 10, 323—Eratosthenian Period, 10, 323—Late Imbrian Epoch, 10, 323—Nectarian Period, 10, 323—Pre-Nectarian Period, 10, 323Apollo missions—Apollo 11, 175, 219—Apollo 12, 85, 137—Apollo 14, 90—Apollo 15, 153, 204, 205—Apollo 16, 170—Apollo 17, 224Apennine Bench, 152Apollo astronauts—Aldrin, Buzz, 175, 219—Armstrong, Neil, 175, 219—Bean, Alan, Apollo, 85, 137—Cernan, Eugene, Apollo, 224—Conrad, Charles (Pete), 85, 137—Duke, Charles, Apollo, 170 —Irwin, James, 153, 204, 205—Mattingly, T. Kenneth, 213—Mitchell, Edgar, 90—Schmitt, Harrison (Jack), 224—Scott, David R., 153, 204, 205—Shepard, Alan, 90—Young, John, 170Aristarchus Plateau 121, 122Army Mapping Service, 7

Basin ejecta blankets, 9Basins, 9—Australe, 244, 245, 248, 250,

259–261, 290, 322—Bailly, 290, 291, 294, 295, 297, 299,

302—Balmer-Kapteyn, 244, 245, 249—Cardanus-Herodotus, 101, 116—Crisium, 244, 245, 248, 250, 254,

260, 261—Fecunditatis, 155, 193, 194,

197–199, 228, 231, 232, 244—Flamsteed-Billy, 101—Grimaldi, 13, 14, 41, 49, 54—Humboldtianum, 234, 243, 253,

255, 263, 264, 285–290

General Index

Albedo feature—Reiner Gamma, 114

Catena (chain of craters)—Abulfeda, 169—Brigitte, 224—Davy, 94, 98—Deslandres, 94—Humboldt, 262—Krafft, 43—Littrow, 224—Sylvester, 269—Taruntius, 235—Timocharis, 144—Yuri, 1Craters —Abel, 261—Abulfeda, 165, 169—Agrippa, 208—Airy, 161—Alexander, 212—Aliacensis, 96, 159, 160—Alphonsus, 98—Amundsen, 301, 304, 308, 312,

316, 320—Anaxagoras, 276, 280—Anaximenes, 268, 272—Annegrit, 135—Anville, 194, 235—Apianus, 159, 160, 164, 165—Aristarchus, 121, 122—Aristillus, 153—Aristoteles, 282, 283—Aston, 103—Atlas, 226, 227, 230, 247—Atwood, 199, 249—Autolycus, 153, 205—Baade, 20, 296—Babbage, 267, 270, 271—Baco, 157, 311—Baillaud, 284, 288, 290—Bailly, 295, 297, 299, 300—Balmer, 249, 251—Barnard, 261, 262—Barocius, 158, 163—Barrow, 280—Bartels, 27, 103—Bayer, 60, 303—Beer, 144, 147—Berosus, 253, 255—Berzelius, 233, 238, 247—Bessarion, 128—Bessel, 215—Bianchini, 124, 274—Biela, 176, 185, 315, 318, 319—Bilharz, 199, 249

Craters (continued)—Billy, 64—Blagg, 202—Bode, 150—Bohnenberger, 183, 189—Bohr, 26, 34—Borda, 188, 194—Bouguer, 124, 274—Boussingault, 319—Brayley, 128—Brisbane, 191, 195, 319—Buisson, 262—Bullialdus, 83, 84—Burckhardt, 238, 240, 241, 247,

253—Burg, 217, 223—Burnham, 161, 165—Byrd, 269, 273, 277, 281, 285, 289,

317—Byrgius, 46, 47, 54—Campanus, 78, 79—Capuanus, 73, 78—Cardanus, 43—Carmichael, 228, 231—Carpenter, 272—Carrington, 239, 242, 247, 253—Casatus, 302, 305—Cassini, 154—Catalan, 296—Cauchy, 228, 231—Cayley, 213—Censorinus, 184, 224, 228—Cepheus, 230, 233, 247—Challis, 277, 281, 285—Charles, 135—Chevallier, 230, 233, 247, 253—Clausius, 62—Clavius, 60, 71, 80, 306, 307—Cleomedes, 237, 238, 240, 241,

246—Cook, 194—Copernicus, 138, 143—Couder, 18—Crozier, 194—Cruger, 48, 54—Curie, 261, 262—Cusanus, 288, 290, 320—Cuvier, 91, 157, 310, 311—Cyrillus, 174—da Vinci, 231—Daguerre, 183—Damoiseau, 54—Darney, 84—Darwin, 47, 48—De La Rue, 227, 230, 234, 286, 287,

290—Debes, 232, 237, 238

Craters (continued)—Descartes, 169—Deslandres, 87, 93, 96, 97—Diana, 228—Diophantus, 128, 129—Drygalski, 294, 298, 299—Eddington, 44—Eichstadt, 30, 39—Einstein, 26, 27, 103, 266—Endymion, 227, 230, 234, 247, 287,

290—Euclides, 79—Eudoxus, 212—Euler, 129, 134—Faraday, 95, 138, 158—Fauth, 137, 143—Felix, 135—Feuillee, 144, 147—Flamsteed, 70—Fontana, 59—Fourier, 58, 59, 62—Fra Mauro, 90—Fracastorius, 179, 182, 183—Franklin, 230, 233, 247—Furnerius, 192, 196, 248—Galle, 282, 283—Gambart, 90, 143—Gartner, 283, 286—Gassendi, 69, 75—Gaudibert, 183—Gauss, 253, 255—Geminus, 238, 241, 247, 253—Gemma Frisius, 164—Gerard, 104, 146—Gioja, 269, 273, 277, 281, 285—Glushko, 42, 43—Goclenius, 189, 194—Goddard, 254, 257—Goldschmidt, 276, 280—Goodacre, 164, 167—Grace, 228—Graff, 20, 296—Grimaldi, 49, 54, 103—Guericke, 89, 94—Gum, 260—Gutenberg, 184, 190—Guthnick, 296—Haidinger, 72, 77—Hainzel, 66, 72—Hale, 321—Hanno, 185, 191, 195, 319—Harlan, 250—Harpalus, 113, 218, 271, 274—Hartwig, 32, 41—Hausen, 295, 297—Hayn, 290—Hecataeus, 251

—Hedervari, 320—Hedin, 33, 42—Heinsius, 77—Helicon, 130, 136—Hell, 87, 93, 94—Henry, 54—Henry Freres, 54—Hercules, 226, 227, 230, 247—Hermite, 266, 269, 273, 277—Herodotus, 116, 121—Hesiodus, 82, 87, 88—Hevelius, 49—Hill, 228—Hind, 165—Hippalus, 74, 79—Hipparchus, 162, 165—Hommel, 157, 314—Hooke, 233, 239, 247, 253—Hortensius, 132, 137—Hubble, 254, 258—Huggins, 86, 92—Humboldt, 250, 261, 262—Hyginus, 203, 208—Idel’son, 308, 320—Inghirami, 28, 37—J. Herschel, 271, 272, 274—Jacobi, 91, 310, 311—Jansen, 224—Jansky, 254, 256, 257, 262—Janssen, 171, 177, 180—Jeans, 322—Jenner, 260—Joliot, 254, 258—Joy, 204, 210—Kapteyn, 249—Kepler, 128—Kies, 82—Kiess, 262—Kirchoff, 225, 229—Klaproth, 302, 305—Konig, 78, 79, 83—Kopff, 23—Krusenstern, 159, 160—Kugler, 259—La Caille, 97, 140, 160—La Condamine, 124, 131, 274, 275—Lade, 165, 208—Lagrange, 38, 46—Lalande, 94—Lamarck, 39, 47—Lamb, 260—Lambert, 139, 140—Lame, 249—Langrenus, 198, 199, 249—Lassell, 94—Lavoisier, 103, 105, 106, 206—Lawrence, 231

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All of the annotated features are listed here, with the exception of the craters. These craters are only those that are mentioned at least once in the notes. For afull list of annotated craters, see the CD.

Craters (continued)—Le Gentil, 294, 299—Le Monnier, 222, 224, 225—Le Verrier, 136—Leakey, 184, 228—Lebedev, 259—Letronne, 69, 70—Licetus, 91, 92, 95, 138, 158—Lichtenberg, 107, 108—Lilius, 80, 91, 310—Lindenau, 167, 172, 173—Linne, 210, 211—Lohrmann, 49, 54—Lohse, 198—Longomontanus, 71, 72, 77, 306—Luther, 216, 222—Lyapunov, 254, 258—Lyell, 228, 231—Lyot, 322—Madler, 179—Maestlin, 125, 128—Magelhaens, 189—Maginus, 80, 86, 92, 307, 310—Main, 277, 281, 285—Mairan, 118, 123—Malapert, 298, 301, 304, 308—Manilius, 209—Marco Polo, 151—Marinus, 248, 250—Markov, 267, 270—Mason, 217, 223—Maunder, 17, 23—Maupertuis, 131, 274, 275—Maurolycus, 95, 138, 158, 163—Maury, 226, 230—Mavis, 135—McClure, 194—Mee, 61, 66, 72—Menelaus, 214—Mercator, 78, 79, 82, 83—Mercurius, 239, 242, 253, 255—Messala, 239, 242, 247, 253—Messier, 194, 235—Meton, 280, 284, 290—Milichius, 133—Miller, 92, 95—Milne, 262—Monge, 189, 194—Moretus, 305, 309—Moseley, 27, 103—Murchison, 150, 202—Mutus, 311, 314—Nansen, 289, 317—Naonobu, 199, 249—Nasireddin, 92, 95—Nasmyth, 36, 51, 52, 300—Neander, 181, 182, 187—Nearch, 314, 315, 319—Neper, 254, 256, 257, 262—Neumayer, 321—Newcomb, 229, 231, 232, 247—Newton, 302, 305—Nicholson, 21, 22, 30—Nicollet, 88, 94—Nobile, 316—Noggerath, 51, 57—Oenopides, 267, 270—Oersted, 230, 233, 247—Oken, 248, 250—Orontius, 86, 92—Pallas, 150, 202—Peary, 269, 273, 277, 281, 285, 289,

317—Petavius, 197, 248—Petermann, 288, 290—Pettit, 21

Craters (continued)—Philolaus, 272, 276—Phocylides, 36, 51—Piazzi, 46—Piazzi Smyth, 145, 148—Piccolomini, 178, 179, 181—Pingre, 19, 295, 297—Pitatus, 87, 88, 93, 94—Plana, 217, 223—Plato, 142, 278, 279—Playfair, 160, 165—Plinius, 220—Plutarch, 252, 254—Pons, 167, 168, 173—Pontanus, 164, 165, 167, 168—Pontecoulant, 185, 191, 319—Posidonius, 222, 225—Priestly, 259—Prinz, 121, 122, 125—Ptolemaeus, 98, 99, 162—Puiseux, 67, 68, 73, 74—Pupin, 146—Purbach, 96, 97, 140—Pythagoras, 266, 267, 268, 270—Rabbi Levi, 167, 172—Reaumur, 99, 162, 202—Regiomontanus, 96, 97, 159—Reichenbach, 187, 188, 193, 194—Reimanus, 185, 191, 192, 319—Reinhold, 137—Repsold, 104, 146, 266, 267—Riccioli, 41, 42, 49—Riccius, 166, 172—Rocca, 48—Romer, 225, 228, 229—Rosse, 183—Rost, 51, 60, 303—Rothmann, 172, 173, 178, 179—Russell, 35, 44, 105, 107—Sampson, 140, 144—Santbech, 188, 189—Saussure, 86, 92—Scheiner, 60, 303, 306—Schickard, 45, 52, 57—Schiller, 51, 60, 61, 303—Schluter, 32—Schomberger, 309, 313—Scott, 301, 308, 312, 316—Shaler, 21, 29—Shoemaker, 308—Shuckburgh, 233, 239, 247, 253—Sirsalis, 54—South, 113, 218, 270, 271—Steinheil, 176, 180, 186, 319—Stevinus, 193—Stiborius, 172, 178—Stofler, 95, 158—Strabo, 287, 290—Struve, 35, 44, 105, 266—Suess, 119, 125—Sulpicius Gallus, 210—Sundman, 26—Tacchini, 256, 262—Tannerus, 157, 311, 314—Taruntius, 235, 246—Tempel, 208, 213—Thales, 286, 287, 290—Theaetetus, 154, 205—Thebit, 94, 97—Theophilus, 174, 179—Timocharis, 143, 144, 147—Tisserand, 231, 237, 246—Torricelli, 179—Triesnecker, 202—Tycho, 86—Vasco da Gama, 26, 34

Craters (continued)—Vega, 192, 196, 248, 319—Vendelinus, 198, 249—Verne, 135—Vieta, 53, 54, 58, 59—Vitello, 67, 68, 73, 74—Vlacq, 176, 314, 315—von Braun, 104, 106, 146, 206—Voskresenskiy, 27, 103, 104, 146—W. Bond, 280—Wallace, 146—Wallach, 224, 228—Wargentin, 36, 45, 300—Weigel, 51, 303—Weinek, 181, 182—Werner, 96, 97, 159, 160—Wexler, 321—Wildt, 252, 254—Wilhelm, 72, 77—Wilkins, 167, 168—Wolf, 88—Wright, 21, 22—Yakovkin, 19, 296—Young, 186, 192—Zagut, 167, 172, 173—Zahringer, 231—Zollner, 170, 175—Zucchius, 300, 303

Dorsum, Dorsa (mare ridge, ridges)—Dorsa Aldrovandi, 222—Dorsa Andrusov, 199—Dorsa Argand, 126—Dorsa Barlow, 224—Dorsa Burnet, 111, 116, 117—Dorsa Cato, 194—Dorsa Dana, 256—Dorsa Ewing, 69, 75, 76—Dorsa Geikie, 199—Dorsa Harker, 246—Dorsa Lister, 215, 221—Dorsa Mawson, 199—Dorsa Rubey, 70—Dorsa Smirnov, 216, 221, 222—Dorsa Stille, 139—Dorsa Tetyaev, 246, 252—Dorsa Whiston, 111, 116, 117,

222—Dorsum Arduino, 128—Dorsum Azara, 215, 216—Dorsum Bucher, 126—Dorsum Buckland, 210, 214, 215—Dorsum Cayeaux, 194—Dorsum Cushman, 194—Dorsum Gast, 210—Dorsum Grabau, 143, 144—Dorsum Guettard, 89, 90—Dorsum Heim, 129, 135—Dorsum Higazy, 143, 144—Dorsum Nichol, 220, 221—Dorsum Niggli, 116, 117—Dorsum Oppel, 246—Dorsum Owen, 210—Dorsum Scilla, 111—Dorsum Termier, 246—Dorsum Von Cotta, 210, 211—Dorsum Zirkel, 134, 135, 139,

140

Mare (sea), 8—Anguis, 240, 246, 252, 253—Australe, 191, 195, 259–261, 322—Cognitum, 84, 85—Crisium, 237, 240, 246, 249, 252

Mare (continued)—Fecunditatis, 190, 194, 198, 199,

231, 235, 240, 249—Frigoris, 124, 131, 227, 230, 271,

274, 275, 278, 286—Humboldtianum, 243, 290—Humorum, 62, 63, 73, 74—Imbrium, 130, 131, 133, 136, 139,

140, 143–145, 147, 148, 151, 266—Insularum, 85, 90, 132, 137—Marginis, 254, 257, 262—Nectaris, 179, 183—Nubium, 78, 79, 83, 87– 89, 93, 94—Orientale, 17, 23, 103—Serenitatis, 210, 211, 214–216,

222, 224—Smythii, 251, 256, 262—Spumans, 249—Tranquillitatis, 175, 179, 220, 224,

228, 231—Undarum, 249, 251—Vaporum, 151, 209Mons, Montes (mountain,

mountains)—Mons Ampere, 152—Mons Argaeus, 224—Mons Bradley, 152, 204—Mons Delisle, 128—Mons Esam, 228—Mons Gruithuisen Delta, 123, 126—Mons Gruithuisen Gamma, 123,

126—Mons Hadley, 204, 205—Mons Hadley Delta, 204—Mons Hansteen, 64—Mons Herodotus, 116, 117—Mons Huygens, 152—Mons La Hire, 134, 135, 139—Mons Maraldi, 228—Mons Moro, 84—Mons Penck, 175—Mons Pico, 145—Mons Piton, 148, 154—Mons Rumker, 109, 112—Mons Usov, 246—Mons Vinogradov, 128, 134—Mons Vitruvius, 224—Mons Wolff, 151—Mont Blanc, 148, 154—Montes Agricola, 111, 116, 117—Montes Alpes, 142, 148, 149, 154,

279—Montes Apenninus, 151, 152, 204,

205—Montes Archimedes, 152—Montes Carpatus, 133, 138, 143—Montes Caucasus, 154, 205—Montes Cordillera, 18, 21, 24, 29,

30, 31, 32—Montes Haemus, 209—Montes Harbinger, 122, 126—Montes Jura, 123, 124, 127—Montes Pyrenaeus, 183, 189—Montes Recti, 131, 142, 150—Montes Riphaeus, 79, 85—Montes Rook, 18, 21, 22, 23, 24,

30, 31—Montes Secchi, 231—Montes Spitzbergen, 147—Montes Taurus, 228, 229, 231—Montes Teneriffe, 142, 145, 150,

275, 278

Oceanus Procellarum, 59, 65, 70, 76,79, 100–122, 125, 128, 266, 267

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Palus (swamp)—Epidemiarum, 73, 74, 78, 79, 82—Putredinis, 152, 153, 204, 205Promontorium (promontory)—Agassiz, 148, 154—Archerusia, 220—Deville, 148, 154—Fresnel, 204, 205—Heraclides, 127, 130—Kelvin, 73, 74—Laplace, 130, 136—Taenarium, 94

Rima, Rimae (rille, rilles)—Rima Agatharchides, 79—Rima Agricola, 117—Rima Ariadaeus, 208, 213—Rima Billy, 64—Rima Birt, 94—Rima Bradley, 152, 153, 204—Rima Brayley, 125, 128—Rima Calippus, 212—Rima Cardanus, 43—Rima Carmen, 224—Rima Cauchy, 228—Rima Cleomedes, 240, 246—Rima Cleopatra, 117—Rima Conon, 204—Rima Dawes, 224—Rima Diophantus, 128, 129—Rima Draper, 133—Rima Euler, 134—Rima Flammarion, 99, 150—Rima Furnerius, 196, 248—Rima G. Bond, 225, 229—Rima Galilaei, 115—Rima Gartner, 286—Rima Gay-Lussac, 138

Rima, Rimae (continued)—Rima Hadley, 153, 204, 205—Rima Hansteen, 59, 64—Rima Hesiodus, 82, 83, 87—Rima Hyginus, 203, 208, 209—Rima Jansen, 224—Rima Krieger, 122—Rima Mairan, 118, 123—Rima Marius, 120—Rima Milichius, 128, 132—Rima Oppolzer, 162, 202—Rima Reaumur, 162, 202—Rima Rudolf, 224—Rima Schroter, 99, 150—Rima Sharp, 112, 113, 118, 218—Rima Suess, 120, 125—Rima T. Mayer, 133—Rima Vladimir, 152—Rima Yangel’, 203—Rimae Alphonsus, 98—Rimae Apollonius, 240—Rimae Archimedes, 152—Rimae Aristarchus, 116, 117, 121,

122—Rimae Arzachel, 98—Rimae Atlas, 227, 230—Rimae Bode, 150, 151—Rimae Boscovich, 209—Rimae Burg, 212, 217, 223—Rimae Chacornac, 225—Rimae Daniell, 217, 223—Rimae Darwin, 47, 48, 54—Rimae de Gasparis, 58, 59, 63—Rimae Doppelmayer, 62, 63, 67, 68—Rimae Fresnel, 153, 205—Rimae Gassendi, 69, 75—Rimae Gerard, 104, 146—Rimae Goclenius, 189, 190—Rimae Grimaldi, 54

Rima, Rimae (continued)—Rimae Gutenberg, 184, 190—Rimae Hase, 248—Rimae Herigonius, 75—Rimae Hevelius, 49—Rimae Hippalus, 73, 74, 78, 79—Rimae Hypatia, 175, 219—Rimae Janssen, 171, 177—Rimae Kopff, 23—Rimae Liebig, 63—Rimae Littrow, 224—Rimae Maclear, 214, 220—Rimae Maestlin, 128—Rimae Maupertuis, 131, 275—Rimae Menelaus, 214—Rimae Mersenius, 63, 64, 68, 69—Rimae Opelt, 89—Rimae Palmier, 62—Rimae Palmieri, 63—Rimae Parry, 90—Rimae Petavius, 197, 248—Rimae Pitatus, 87, 88, 93, 94—Rimae Plato, 142, 147, 149, 279—Rimae Plinius, 220—Rimae Posidonius, 222, 225—Rimae Prinz, 121, 122, 126—Rimae Ramsden, 73, 74, 78—Rimae Repsold, 104, 146—Rimae Riccioli, 41, 42, 49—Rimae Ritter, 213, 219—Rimae Romer, 224, 225, 228, 229—Rimae Secchi, 231—Rimae Sirsalis, 47, 54, 59—Rimae Sosigenes, 213, 214, 219, 220—Rimae Sulpicius Gallus, 210—Rimae Taruntius, 235—Rimae Theaetetus, 153, 205—Rimae Triesnecker, 202, 208—Rimae Vasco da Gama, 34

Rima, Rimae (continued)—Rimae Zupus, 59Rupes (scarp)—Altai, 172, 173, 178, 179—Boris, 129—Cauchy, 228—Kelvin, 73, 74—Liebig, 62, 63—Mercator, 78, 79, 82, 83—Recta, 94—Toscanelli, 121, 122

Sinus (bay)—Aestuum, 151—Amoris, 228, 231—Asperitatis, 175, 179, 219—Concordiae, 231—Fidei, 203—Honoris, 214—Iridum, 123, 124, 127, 130—Lunicus, 147—Medii, 99, 150, 162—Roris, 112, 113, 218, 270, 271—Successus, 240, 249

Vallis (valley)—Alpes, 149, 154, 279, 282—Baade, 20, 28, 296—Bohr, 26—Bouvard, 20, 21, 28, 29—Capella, 184—Inghirami, 28, 37—Palitzch, 248—Rheita, 180, 185, 186, 192, 319—Schrodinger, 322—Schroteri, 116, 117, 121, 122—Snellius, 188, 193, 194 3

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