REPORT ON THE GENERAL GEOLOGIC HISTORY OF THE MESA NTMS

QUADRANGLE WITH ACCOMPANYING 1:250,000 COMPILATION MAPS OF

GEOLOGY AND METALLIC MINERAL OCCURRENCES

by Robert B. Scarborough

Arizona Geological Survey Open.File Report 79·3

September, 1979

Arizona Geological Survey 416 W. Congress, Suite #100, Tucson, Arizona 85701

This report is preliminary and has not been edited or reviewed for conformity with Arizona Geological Survey standards

TABLE OF CONTENTS

INTRODUCTION -----------------------------------------PHYSIOGRAPHY --------------------------------------GEOLOGIC HISTORY -------------------------------

Older Precambrian ---------------------Mazatzal Orogeny ___________________ __

Younger Precambrian ---------------------Paleozoic Era ---------------------------

Regional Statement~--~------------__ Paleozoics in Mesa Quad --------------

Mesozoic, pre-Laramide History ________ __

Laramide Orogeny ------------------------Cenozoic (Pre-Basin and Range Time) ------Metamorphic Core Complexes ___________ __

Basin and Range Disturbance ----------Basin and Range Volcanism -------------Pleistocene ---------------------------Globe-Miami Example -------------------

STRONTIUM ISOTOPE GEOCHEMISTRY ---------------------------POTASH-SILICA RELATIONSHIPS ----------------------------CURRENT MINING IN THE MESA QUAD ______________ __

URANIUM EXPLORATION IN THE MESA QUAD _____ ------REGIONAL CROSS SECTIONS ___________________ .,................,...,......,...,.-,-

FIGURES ------------------------------------------------REFERENCES General References ------ ---------------------

Relevant MS and Ph.D. Theses _________ _

Uranium Related References _________ _

1

2

4

4

6

7

9

9 10

12

13

17

22

23

26

26

27

27

29

30

32

35

37

68

74

76

FIGURES

1. Physiographic provinces and post-10 m.y. volcanic rocks in Arizona.

PRECAMBRIAN

37

2. Precambrian stratigraphic relations, central Arizona. 38

2a General stratigraphic sections, central Arizona. 39

3. Columnar section, Apache Group sediments. 40

4. Statewide outcrop map of Apache Group sediments. 41

5a Post-Troy N-S cross section through central Arizona. 42

5b Late Devonian N-S cross section through central Arizona. 42

6. Outcrops of Apache Group sediments and diabase. 43

PALEOZOIC

7. Total Paleozoic isopach map of Arizona. 44

8. Thickness profiles of Arizona Paleozoic strata. 45

9. Permian isopach map of Arizona. 46

10. Paleozoic nomenclature of central Arizona. 47

11. Apache Group - lower Paleozoic relations, central Arizona. 48

12. Karst sinkholes in Redwa11 Limestone, Gila County. 49

MESOZOIC

13. Jurassic evaporites and Laramide overthrusts, western U.S. 50

14. Laramide plutons in southern Mesa quad. 51

15. Laramide dike orientations. 52

16. Histogram for Laramide and mid-Tertiary K/Ar dates. 53

CENOZOIC

17. Volcanics of the Superstition volcanic field. 54

18. Three cauldrons, Superstition volcanic field. 54

18a Volcanic stratigraphy, Superstition volcanic field. 55

FIGURES (Cont.)

18b Trends of Cenozoic K/Ar dates, Arizona.

19. Mid-Tertiary dike orientations.

20. Attitudes of Oligocene and Miocene layered rocks.

21a Arizona metamorphic core complexes.

21b Details of metamorphic core complex stratigraphy.

22. General relationship of rocks, Globe-Miami area.

GEOCHEMISTRY

56

57

58

59

59

60

23. Strontium initial ratios, tabular data. 61

24. Strontium initial ratio growth diagram, central Arizona. 63

25. Strontium initial ratios for mid-Tertiary rocks. 64

26. Paleozoic stratigraphy along Mogollon Rim. 65

27. Potash-Silica diagram for Arizona igneous rocks. 66

28. General Cenozoic stratigraphy, southern Arizona. 67

INTRODUCTION

This report is a brief compilation of the general geologic

history of the Mesa 10 x 20 NTMS quadrangle of east-central Arizona

(33 - 340

N. latitude, 110-1120

W. longitude). References listed at

the end of the report are divided into a general geology section, an

MS and PhD thesis section, listing only works of broad scope or interest,

and a section at the end dealing with uranium occurrences. This report

accompanies a 1:250,000 map of the general geology of the quadrangle

which has an accompanying legend. A separate map shows known mineral

occurrences in the quadrangle. Eight regional cross sections oriented

NE-SW and extending through the Mesa quad are included with the map.

The 1:250,000 scale geologic map has been abstracted from the

1:500,000 scale geologic map of Arizona, published in 1969 by Eldred

Wilson, Richard Moore, and John Cooper, with additional data from post-

1969 USGS mapping and other published and unpublished sources. In

particular, one may note contact revisions pertaining to Laramide

intrusives, Oligocene and Miocene sediments, and inclusion of larger

Laramide and Late Tertiary dike swarms.

The author much appreciates the editorial review and comments of

Dr. H. Wesley Peirce, Stanley B. Keith, and Anne Candea, all of the

Arizona Bureau of Geology, Geologic Survey Branch.

1

PHYSIOGRAPHY

Arizona may be divided into three provinces based upon physio-

graphy, as illustrated in Figure 1. The northeastern third of the

state is part of the southwestern Colorado Plateau, which consists

of gently warped and arched Paleozoic and Mesozoic sediments. The

Plateau is elevated to 6,000-7,500 feet above sea level at its sou-

thern and western margins, and gently slopes towards the northeast

so that elevations in the Four Corners region range from 4,000-6,000

feet.

The southwestern half of the state is part of the southern Basin

and Range province, which consists of broad, flat valleys broken only

by a series of disconnected, generally N-S elongated mountain ranges.

Valley floor elevations rise in all directions from near sea level at

Yuma to 1,500 ± feet near Phoenix, 2,000 ± feet near Lake Mead (just

below the Grand Canyon gorge) and up to 4,500-5,000 feet in parts of

southeastern Arizona. Mountain "islands" rise above the adjacent val-

ley floors by 1-2,000 feet in southwestern Arizona, by 2-4,000 feet in

the northwestern part of the state and 4~6,000 feet in the southeastern

part of the state.

Separating the Colorado Plateau and Basin and Range provinces is

the Transition Zone, so named because of its pronounced transitional

physiography, Phanerozoic stratigraphy and tectonic involvement, when

compared to its neighbors. The Mesa quadrangle in this scheme spans

the Basin and Range/Fransition Zone interface, as seen in Figure 1.

The Mogollon Rim (Figure 1) is a sharply defined south- to west-facing -

escarpment which defines the southern boundary of the Colorado Plateau.

2

The Rim is best developed on the cliff-forming Permian Coconino

Sandstone and Kaibab Limestone. The Rim boundary passes in an

east-west direction, 15-30 miles north of the northern boundary

of the Mesa quadrangle.

3

GEOLOGIC HISTORY

Older Precambrian

The major features of the Precambrian history of central

Arizona are discussed by Livingston and Damon (1968), Gastil (1958),

Ludwig (1974), and Conway (19761. Re:J;er to Ugures 2 and 2a for a

geological column of the Precambrian of the area.

The oldest rocks in central Arizona are termed the Yavapai

Schist or the Yavapai Group (Wilson, 1939). These are several

discontinuous sequences of volcanic-sedimentary rocks, unmeta­

morphosed in some areas, and severely deformed in others. A

composite thickness of the Yavapai Group, perhaps only a poor

estimate, is 40-50,000 feet. The Yavapai rocks include volcanics

of andesitic-to-mafic composition with massive rhyolite flows in a

few areas, intercalated fanglomerates (submarine?), greenstones,

shales, mudstones, and some clean quartzites. Wilson (1939) di-

vided the Yavapai Group into (oldest to youngest) the Yeager Green­

stone, now the Ash Creek Group (altered mafic flows and sediments,

greater than 2,000 feet thick), the Red Rock Rhyolite (flows, brec­

cias, agglomerates, and minor intrusives, greater than 1,000 feet

thick), and the Alder Series (shales, mudstones, quartzites and con­

glomerates, locally metamorphosed to slates through schists, and greater

than 5000 feet thick). These three units are found only in tectonic

contact with each other. See Ludwig (1974) and Conway (1976) for

recent revisions of stratigraphy based upon their PhD fieldwork.

A series of age dates have been run on Older Precambrian rocks

in the central part of the state (Anderson and Silver, 1976). Most

are U-Pb discordia dates; other Rb-Sr dates are usually in agreement

with these assignments. The Red Rock Rhyolite is dated at 1715 m.y.

4

The Yavapai Group rocks of Wilson are intruded by a series of plutons

ranging from 1,670 to 1,770 m.y. Dates in the west-central part of

the state on volcanics intercalated into Yavapai rocks range from

1,770 to 1,820 m.y. Farther east and south, initiation of volcanism,

as in the Mazat~a1 Range, was at about 1,720 m.y. Only one rock in

the state has been dated to be older than the above mentioned rocks;

and that is a gneiss in the Grand Canyon with a Rb-Sr whole rock date

of about 2,000 m.y. (Clark, et, aI., in press). Ages of 1,730 m.y.

or younger on older Precambrian rocks extend through the Globe-Miami

area and southward. There is a hint in the U-Pb- ;;-:ircon data of

a general younging trend from about 1,800 m.y. to 1,650 m.y. in terrains

extending from the northwest part of the state to the southeast.

These Qlder Precambrian layered rocks, where deformed, are tight1y­

to-openly folded in a series of NE-SW trending, NE plunging (20 - 60)

upright folds (Gasti1, 1958).

Anderson and Silver (1976) describe Arizona's "Yavapai Series"

as resembling "many of the Older Precambrian greenstone belts, charac­

teristically occurring as scattered remnants in silicic cratons." They

suggest that the "Yavapai Series" may represent either island arc ac­

cumulations or else deposits formed on locally downwarped and/or ther-

mally extendedthinn~asia,1ic·crust. They indicate that the very

low potash content of some of the Yavapai mafic volcanics suggests an

oceanic basalt and island arc origin for these rock series.

In central Arizona, the following sediments were deposited, in

ascending order, above the eroded Red Rock Rhyolite: 100-800 feet of

Deadman Quartzite (medium-grained, cross-bedded); 500-1000 feet of

Maverick Shale (gray fissile shale with some quartzite interbeds);

and 1,000-3,800 feet of Mazatzal Quartzite (cliff-forming, fine-to-

5

--medium grained, cross-bedded and ripple-marked). These sediments

are clearly intruded by 1,400 m.y. granites, but are only in fault

contact with the older, 1,600-1,700 m.y. granites. L. Silver of

Cal. Tech. has a 1,720 m.y. zircon age on a rhyolite flow (or

reworked rhyolite detritus), intercalated into the lower Mazatzal

Quartzite near Pine. Livingston (1969) correlates a sedimentary

section of Older Precambrian sandstones and shales just south of the

Salt River, 20 miles north of Globe with the above sedimentary section

of the Mazatzal Mountains. Here, the sediments rest disconformab1y on

the Redmond Rhyolite, a flow mass dated at 1510 m.y. (Rb/Sr by Livingston)

and at 1720 m.y. (D/Pb, in Conway, 1976?), which resembles the Red Rock

Rhyolite beneath the Older Precambrian sediments of the Mazatzal Mountains.

The D/Pb date is probably the more trustworthy of the two in this case.

The City Creek Series is a 2,000 foot thick pile of gray and red

shales and minor quartzites which are judged by degree of deformation

to be younger than the Mazatzal Quartzite, and older than the Apache

Group. These rocks are found in the northern Mazatzal Mountains, and

have no known equivalents. Livingston (1969) has an unpublished 1300 m.y.

age on a thin diabase sill cutting the City Creek Series.

Mazatzal Revolution

The Mazatzal orogeny or revolution of Wilson (1939) is defined as

that tectonic event that follows the deposition of the Mazatzal Quartzite and

precedes the deposition of the Apache Group sediments. As defined,

it only loosely coincides with the intrusion of massive amounts of quartz

monzonite to granite intrusives and related stocks and dikes of diorite,

pyroxenite and rhyolite porphyry. The Oracle and Ruin granites (included

in "pg" on the map) are of this group. Structurally, the

6

orogeny in its type area in the Mazatzal Mountains was characterized

by "subparallel folds, thrust faults and imbricate, steeply dipping

reverse faults, generally of northeastward to northward trend"

(Wilson, 1939, p. 1161). Precambrian granites of the Mesa quadrangle

contain age dates ranging from 1,450 to 1,350 m.y.; this age range

dates the culmination of Wilson's Mazatzal Revolution as originally

defined (Livingston, 1969). In addition, at least two earlier locally­

recognized and unnamed deformations (Gastil, 1958) have affected some

of the Older Precambrian rocks of the region.

Younger Precambrian

All Older Precambrian rocks, including the 1,400 m.y. granites

were attacked by an extensive period of erosion, with the resultant

surface becoming the depositional base of the Younger Precambrian

Apache Group sediments and Troy Quartzite. These sediments, found

in the north central and south central Mesa quad, were extensively

intruded by large masses of diabase, which, in many areas, were

concordantly intruded as sill masses, and vertically inflated the

Apache Group section by a large amount. Chemically, the diabase

contains K2

0 = 0.3 to 2.2%; Si02

= 43.8 to 47.2%, according to

Granger and Raup (1969). Figure 3 gives a columnar description of

the Apache Group sediments and their approximate thicknesses in the

Mesa Quad.

The Apache Group sediments consist of the Pioneer Shale with

basal Scanlon Conglomerate, overlain in turn by the Dripping Spring

Quartzite with basal Barnes Conglomerate, the Mescal Limestone and

uppermost basalts. Throughout most of the Mesa quad, the Apache Group

sediments were deposited on Pinal. Schist and 1400 m. y. granites.

7

In the northwest corner, they were deposited on granites and Older Pre­

cambrian metasediments of Wilson's Yavapai Group. Williams (1957) suggests

flow directions for the Sierra Ancha Mountains region for these times

as toward the SW, Wand NW. Other imbrication directions for the

Barnes Conglomerate at Canyon Creek suggest flow toward the south

(H.W. Peirce, pers. comm). Preserved patches of Apache Group sedi-

ments are only recognized in parts of southern Arizona, as sketched

in Figure 4. Considerable attention, mentioned later, has been given

to certain Apache Group sediments because of their uranium potential.

The Troy Quartzite rests disconformably upon the upper Apache

Group sediments, but is best preserved where protected in post-Troy,

pre-Paleozoic grabens (Krieger, 1961). Radiometric ages on

the extensive diabase sills, which intrude all these sediments, range

from 1,050 to 1,200 m.y., averaging perhaps 1,150 m.y. In the Mesa

quad, the Younger Precambrian sediments are generally not found west

of a north-south line through Roosevelt Lake, and are eroded

away or covered in the eastern quarter of the quadrangle (except

for a small patch preserved near Mt. Turnbull). The younger Pre­

cambrian sediments may be related in age to the Unkar Group sediments

the Grand Canyon region.

Figure 5 is a pair of NNW-SSE cross-sections from Shride (1967)

which illustrates the kinds of events that were interpreted to have

occurred in central Arizona in post-Troy, pre-diabase time (Figure Sa)

and in latestDevonian time (Figure 5b). These cross-sections empha­

size a gentle Apache-Troy disconformity, the extensive nature of the

diabase intrusions, and a hypothesized pre-Devonian, post-Troy horst

and graben terrain of the Mesa quad. Abrupt thickness variations

of Cambrian rocks in the region indicate the presence of a very ir-

8

regular surface of Cambrian deposition (Hammer and others, 1962).

Figure 6 is a map from Shride (1967) which shows the relative pro­

portions of Apache Group sediments and diabase where they outcrop

together.

Paleozoic Era

Regional Statement

Figures and ideas for this section are taken from Peirce (1976),

and USGS quadrangle maps in the area.

The general geometry of Paleozoic rocks in Arizona is shown in

Figure 7 (map) and Figure 8 (several statewide cross-sections) (Peirce,

1976). These figures display a statewide thickness differential of at

least 5,000 feet for Paleozoic rocks. "The maximum contrast occurs

between the thicker sections of both the northwest and southeast cor­

ners and the thinner sections preserved in eastern Arizona between

Canyon de Chelly and Springerville in Apache County. An analysis of

this thinning suggests that only half, and perhaps more, should be

attributed to Paleozoic tectonic manifestations. The remainder is

the result of various combinations of thinning by onlap onto elements

inherited from Precambrian events and erosion in late Paleozoic to

Early Triassic time."

"The larger regional Paleozoic tectonic framework includes: (1)

the Cordilleran miogeosyncline in Nevada; (2) an adjacent shelf zone in

northern Arizona; (3) a positive region in central and eastern Arizona,

and (4) a basining tendency in southeastern Arizona extending northward

from the Sonoran geosyncline and limited to the north and northeast by

the shoaling and positive tendencies mentioned above."

"In northwestern Arizona, the locale of more rapid thickening to­

ward the miogeosyncline is often called a hinge line. The persistence

of this feature, as well as its near-coincident position with the present

9

boundary zone between the Basin and Range and Colorado Plateau pro­

vinces, is of fundamental tectonic significance (Moore, 1972. p. 58).

The positive and shoal region of northern, central and eastern Arizona

is frequently depicted as being a southwestward extension of the Trans­

continental Arch" (Peirce, 1976).

And Peirce notes that the "regional characteristics of the Paleo­

zoic sedimentary rocks indicate that they were affected and controlled

by movements broadly classed as epeirogenic which includes mild tilt­

ing, arching and sagging. Movements tended to be repetitious in space

often reflecting similar directional components, especially northeast,

northwest and northerly trends. The definable tectonic elements ap­

proximate the spatial distribution of younger, regionally prominent

Laramide structures shown on contemporary geologic maps. Even Ceno­

zoic trends reflected in the present physiographic margins of the

Colorado Plateau province in Arizona are parallel to tectonic ele­

ments active during Paleozoic time."

Pa1eozoics in Mesa Quad

Figure 8 cross-section D-G hypothesizes that Paleozoic sediments

once blanketed southern Arizona, in contrast to the remnants of today,

which are visible in the Mesa quadrangle only as a flat-lying, Colorado

Plateau-type sequence in the northeast corner, and as tectonically dis­

turbed and eroded patches in the southern Mountain blocks.

The explanation of today's pattern of Paleozoic outcrops is not

a simple one because of several regionally-based denudationa1 events

which will be discussed later. But their influences is still apparent

on such particular matters as the absence of Permian strata throughout

most of the Mesa quad (Figure 9), which may be explained by pre-late

Cretaceous erosion of the area.

10

Figure 10 shows thicknesses of identified Paleozoic strata from

USGS quadrangle mapping done both north and somewhat south of the Mesa

quad, and in the G1obe-Superior-Christmas area in the south central

part of the quad. A problem remains concerning the differentiation

of the Precambrian Troy Quartzite and the Cambrian Bo1sa and Abrigo

Formations, as noted by Krieger (1961, 1968) and Hammer and others,

(1962). Older literature contains various nomenclature problems for

these units. Cambrian rocks consist of the middle Cambrian Bo1sa

Quartzite and the late Cambrian Abrigo Formation. Both are found

throughout southern Arizona but are missing in generally the nor­

thern half of the Mesa quad under Devonian cover rocks. The Bo1sa

Quartzite rather resembles the Troy Quartzite, even though they are

separated in time by at least 550 m.y., with the result that proper

assignments on geologic maps, given this choice, cannot be guaranteed

outside of the areas where the two are seen together.

Lower Ordovician E1 Paso Limestone is found in the southeastern

part of the state as far northwest as Morenci. However, the Ordovi­

cian and Silurian rocks are entirely missing from the rest of Arizona,

due to erosion or non-de.positii'>n prior to the widespread Devonian

sedimentation event.

The Cambrian units are variously preserved or missing, and frequently

upper Devonian Martin beds are seen depositional on Precambrian

terrain of considerable relief (Figure 11). Recent work at the Univer­

sity of Arizona has suggested the naming of the uppermost Devonian rocks

seen in this region the Percha Formation after similar rocks in New

Mexico (Schumacher and others, 1976).

The Mississippian section is predominantly composed of carbonates,

and commonly displays an upper subaerially eroded contact with karst

11

sinkholes and solution cavity phenomena (Figure 21). These rocks

are the Escabrosa Limestone of southeastern Arizona and the Redwall

Limestone of the Colorado Plateau region.

Pennsylvanian-Permian stratigraphy in the Mesa quad is a complex

mixture because of two different sets of nomenclature for the Colorado

Plateau (mostly clastic rocks) and SE Arizona (mostly carbonate rocks).

See Figure 10. In the region of the Mesa quad, Pennsylvanian rocks are

usually called the Naco Limestone,equivalent to the Horquilla Limestone

to the south and the lower Supai Formation to the north. Permian rocks

are missing in the Mesa quad except for the typical Colorado Plateau

assemblage of Supai-Coconino-Kaibab rocks of the extreme northeast corner

of the quad. Reasons for this follow.

Mesozoic, Pre-Laramide History

If one defines Laramide time as beginning at about 80 m.y. ago,

then the pre-Laramide Mesozoic record of the Mesa quad is represented

by very thin, only locally-preserved patches of clastic sediments in

the extreme south central part of the quad (noted by Willden, 1964)

and similar upper Cretaceous sediments in the northeast part (noted

by Finnell in USGS quads GQ-544 and 545, and McKay in USGS quad GQ-973).

See Miller (1962)for Upper Turonian age assignments on marine Cre-

taceous deposits exposed in the Deer Creek area (near Winkelman) and

the Morenci area. These non-spectacular remnants are in contrast to

the voluminous, earlier Mesozoic volcanics and sediments of southern

Arizona and the famous Triassic-Jurassic-Cretaceous deposits of the

central Colorado Plateau. Similiarly-aged rocks in central Arizona were

either eroded by Turonian time or else not deposited because of the presence

of a Mesozoic "Mogollon Highland" situated in this region. In the

eastern Mesa quad, Cretaceous volcanics and sediments

12

sit on or are in fault contact with Precambrian granite and/or

Paleozoic sediments. South of Tucson, preservation of Paleozoic

and Mesozoic strata increases notably. In the Morenci-Clifton

area, Paleozoic strata with overlying Cretaceous Pinkard Forma­

tion clastics are preserved in places under an Oligocene volcanic

cover; however, in fully half of the Morenci area, the Oligocene

volcanics are deposited directly upon Precambrian granite. The

general picture for the east-central part of Arizona is one of

both late Mesozoic and early to middle Cenozoic erosion which has

left the Mesozoic rocks essentially unrepresented in the Mesa quad.

Laramide Orogeny

The Laramide orogeny, which so profoundly readjusted the Cor­

dilleran landscape by east-west compressive crustal shortening and in­

tense plutonism and volcanism, may have had different kinematic ex­

pressions in different areas of the West. The beautiful low angle

thrust faults and broad folds (Coney, 1976) of areas north of Las

Vegas appear to be replaced in southern Arizona by moderate1y-to­

steeply dipping northwest trending thrust faults and faulted closed

folds, described by some as "basement-cored uplifts" (for example,

Keith and Barrett, 1976). Others, such as Drewes (1976), have suggested

that the extensive low-angle foreland thrust systems of Utah-Idaho-

Wyoming and those of Chihuahua, Mexico are also present in Arizona by

invoking a regiona1ity argument and connecting together various Laramide-aged

thrust segments found in southern Arizona's isolated mountain blocks. Figure

13 graphically portrays this hypothesis. However, the field expression of

large-scale overthrust belts in Arizona is entirely lacking from this writer's

viewpoint, and thus, ,individual Laramide structures appear to be confined

to areas on the scale of one or two adjacent mountain blocks.

13

Much of the folding and faulting exposed in the mountains

of the Mesa quad involving Paleozoic and Mesozoic rocks is of

Laramide age, and, according to Keith (1975) , is bracketed

between roughly 90 and 50 m.y. The entire interval, Superior­

Globe-San Carlos-Winkelman, contains a wide variety of structural

features which occurred in late Cretaceous time and can be grouped

into phenomena created by ENE directed compression on a regional

scale.

Laramide plutons are represented on the Mesa quad in the Santa

Teresa mountains and in the Granite Basin laccolith (both in the SE

corner), in the plutons of the Globe-Miami area, and many smaller

plutons extending throughout the southern part of the quad, including

the Sacaton mountains in the SW corner of the quad. These igneous

rocks (K-Ar dated at 55-70 m.y. in central Arizona; Damon and Mauger,1966;

Banks, et. al., 1972) are noted for their Cu and Mo contents.

Economic deposits of this age are known at Globe and Miami, at Ray,

along the southside of the Sacaton Mountains, and many smaller de­

posits such as at the Christmas mine near Winkelman. Titley and

Hicks (1966) and Jenny and Hauck (1978) have devoted volumes to

the characteristics and geologic setting of these important metali­

ferous deposits in Arizona and adjacent areas.

Detailed geochronologic data on Laramide rocks do not everywhere

exist, especially for non-mineralized stocks. Figure 14, however, in­

dicates their minimal distribution in the southeastern Mesa quad. Most

Laramide plutons usually fall into the quartz diorite to quartz mon­

zonite compositional range (Si02=60-70%, K57 . 5= 1.5 to 2.2, hence

calc-alkaline according to Keith, 1975) with more minor quantities of

mafic plutons and dike masses usually lurking around. Granite as a

rock type is not common compared to granodiorite.

14

Livingston and others (1968) discuss the

geochronology of the Laramide porphyry copper deposits of Arizona,

and also suggest a Cenozoic history relating to their preservation

or removal depending upon whether or not Cenozoic volcanic flows

covered and protected the Laramide plutons.

Laramide-aged volcanics are found on the Mesa quad associated

with the Laramide plutons and in the south-central portion in the

Deer Creek area, and are described by Willden (1964). Here, a thick

pile of andesite-to-basalt flows are intermixed with flow breccias, and

overlie a Cretaceous coal-bearing sedimentary sequence. Together, they

disconformably overlie the Naco ,Formation. The entire Paleozoic and Cre­

taceous section is folded into an asymmetric shallow E-W trending syn­

cline. These Cretaceous volcanics are termed the Williamson Canyon

volcanics in the USGS nomenclature (see Krieger MH, USGS map GQ-ll06,

Winkelman quad map). Some would classify these volcanics, dated by

K/Ar at 75-80 m.y., and chemically belonging to the basalt clan

(Koski, 1979), as pre-Laramide in age.

Laramide dikes, mineralized joints, veins and elongate stocks

in central Arizona show a marked preference towards a N SO-70o

E

orientation, according to Rehrig and Heidrick (1976). See example of

Figure 14. They suggest that this direction is consistent with ENE-WSW­

oriented maximum principal stress, and NNW-SSE-oriented minimum princi­

pal stress for Laramide times (75-50 m.y. ago). Further, they cite

references which suggest up to 6-14% of N-S crustal expansion in the

Tortilla mountains due to dilatational dike emplacement, and up to

25% expansion in the Morenci area (p. 208). Figure 15 illustrates

these data graphically. Clearly, in this diagram, all other orienta­

tions in these areas are subordinate.

15

A Laramide event not as well-defined, is the apparent 1eft­

lateral motion along N700W faults mainly in SE Arizona. There is

some evidence that deep crustal zones of weakness oriented in this

direction (the "Texas Zone") helped in a broad sense to localize

Laramide deposits in their current distribution (Keith, 1978).

Many faults in the south and central Mesa quad have this approxi­

mate orientation and have complex movement histories which in­

clude both normal and reverse movement.

The Canyon Creek fault zone of the north central part of the

quad, and extending another 15 miles northward; is a N-S probable

dip-slip fault with at least two opposing times of movement (Finnell,

1962). He suggests a probable Laramide east-side-down movement of

at least 1,800 feet, and a younger motion (post 21 m.y. according

to Peirce and others, in press) west-side-down at least 1,300 feet,

with a net resultant throw of east-side-down 500 feet. Throw on

the fault decreases in a northerly direction, where the fault be­

comes a monocline. However, more regional arguments based upon

erosional conditions suggest that larger amounts of throw, per-

haps in excess of 5,000 feet in the central Mesa quad have been

masked by the fact that net throw is very small. These arguments are

based upon sources, flow directions, and gradients of Oligocene or

older Cenozoic stream systems which deposited the "rim gravels,"

discussed in next section.

The Laramide interval is a likely candidate for the time of uplift

in an undefined parcel of the Western U.S., including part or all of

Arizona. The late Turonian marine sandstones of the Mogollon Rim region

just north of the Mesa quad are now found at elevations of 7,000-7,500 feet

and their time of elevation, although not known, can probably be more

easily modeled as having occurred pre-rim gravel time. This elevation

16

phenomenon appears more likely to be an epeirogenic event than an

orogenic one; its effects however, are stillapparent in such

phenomena as the extreme elevation of Eocene deposits in SW Utah,

now found at 9,000-11,000 foot elevations.

Finally, the main pulse of Laramide magmatism, as noted pre­

viously, dates at 75-50 m.y. It appears very separate and distinct

from younger Cenozoic magmatism, as is seen in Figure 16. Igneous

rocks in Arizona with dates of 50-40 m.y. are quite rare, but occur

on a series of WNW trending basalt dikes in the Dos Cabezas Mountains

of Cochise Co., and in some enigmatic two-mica granites found associ­

ated with some of the Arizona "metamorphic core complexes."

Cenozoic (pre Basin-and-Range time)

Following the Laramide orogeny in Arizona and preceding the Mid­

Tertiary volcanic cycle, the history of central Arizona seems to be

one of erosion and only limited deposition. The only documented pre­

Miocene Cenozoic deposits in the Mesa quad are the Whitetail Conglomerate

near Ray (Cornwall and others, USGS map GQ-l02l), some red clastic

floodplain deposits in the Tempe area of pre 17 m. y. (andpre-22 m. y. ?)age,

a thick tilted redbed assemblage in the Hayden area (south-central part

of quad), and the "rim gravels" in the northeast corner of the quadrangle,

which are dated as pre-28 m.y. by Peirce and others (in press). These

"rim gravels" blanketed much of the southern margin of the Colorado Pla­

teau, contain flow direction indications of southwest to northeast, and

contain clasts of Precambrian crystalline rocks which logically could

have only come from south of the Plateau edge. The picture, then, for

this Eocene-early Oligocene time is one of a topographic high in central

Arizona shedding debris to the northeast onto what is today the southern

Colorado Plateau.

17

Beginning some time in the Oligocene, there appears to have been

an erosive carving out of central Arizona, at which time much of the

pre-existent Phanerozoic section was stripped from a 100 mile-wide

NW-SE elongate swath through the central part of the State, producing

among other features an ancestral Mogollon Rim (majority of the escarp­

ment of Figure 1). This topographic break acted as a northeastward

limit of deposition to the subsequent voluminous Cenozoic volcanics

and sediments of the southwestern region, including those of the Mesa

quad.

A late Oligocene 10,000 + feet thick redbed sequence about 10

miles west of Hayden, in the south-central part of the Mesa quad

deserves particular interest. The sequence was termed the Hack­

berry Formation by Schmidt, (197~, but later called the San Manuel

Formation by USGS workers in the area, such as Krieger, (19T~. This

writer prefers the first applied name. The sequence dips eastward

at 2D~40o and is composed of fanglomerates, fluvial overbank deposits

and playa-like muds. This package encloses "megabreccia" slide de­

posits, the largest of which is 2.5 miles long and 800 feet thick

(Krieger, 1977). The presence of these megabreccias hints at rapid

tectonic-sedimentation rates, and local relief comparable to that of

today. Tectonic rotation of this sequence apparently does not in­

volve younger fanglomerates of the Big Dome Formation in the area

which are dated at 14-17 m.y. (Krieger and others, 1974) and also

appears to not involve the 20 m.y. old Apache Leap tuff found just

NW of here. This deformation can be modeled as either monoclinal

(compressional) or listric fault (tensional) produced, east side

down, and appears to involve similarly aged sediment-volcanic as­

semblages of the San Pedro valley at least 90 miles farther south.

18

In the Superiar-Glabe area, the pre-mid-Tertiary valcanic, past­

Cretaceaus Whitetail Canglamerate has been invalved in camplex fault­

ing tectonics, with majar mavements an NW and N-S fault sets and sub­

sequent erasian vastly affecting the present autcrap distributian .of

all racks as yaung as Whitetail. Near Ray and the Superiar area, White­

tail beds are 3-5,000 feet thick and rest upan Paleazaic sediments an the

west side .of a N-S ta NNW-trending higb angle fault, but are very thin

(0-200 feet) acrass this fault ta the east, where they rest an Precam­

brian racks and Laramide Schultze granite. Apache Leap tuff thick­

nesses acrass this fault are 1,000 ± feet an bath sides (S.B. Keith,

pers. camm.). Fram this geametry, .one can pastulate pre-Whitetail

(Laramide?) stripping .of the Paleazaic sectian an the east side .of the

fault and a presumed syn- .or past-Whitetail fault reactivatian which cantrals

present-day lacatian .of Whitetail autcraps. By 20 m.y. aga, (Apache Leap tuff

time) faulting an this structure had ceased. See camments an the Canyan Creek

fault zane far a passible analagaus mavement histary.

Several autcraps .of Oligacene-Miacene caarse clastic redbeds are seen

in the extreme west-central part .of the Mesa quad (labeled "OM" an the map),

and .occur as is alated remnants which dip in variaus directians. These can­

tain reddish brawn caarse fanglamerates, mudflaws and fluvial flaadplain

depasits as the daminant lithalagies, and cantain clasts .of Precambrian

granites expased in the area. In certain areas (10 miles NE .of Scattsdale),

there are andesite flaws and agglamerates interbedded .or underlying the

redbeds, which have yielded 15 ta 20 m.y. age dates elsewhere ta the west.

The daminant magmatic actian in sauthern Arizana in the 30 ta 13 m.y.

time slat is the eruptian .of valuminaus ignimbrites with assaciated ande­

sites and plutanic phases (Shafiqullah and .others, 1978). In the Mesa

quad, the Superstitian valcanic field (described by Sheridan, 1978) em­

braced this time and in its main bulk may be campased .of at least three

"cauldrans" (Figs. 17 and 18) .of differing ages. Figure 17 .outlines the

19

minimal, original extent of this volcanic field as defined by

Sheridan, which encompasses very nearly the entire southwestern

quarter of the Mesa quad. Figure 18, from Sheridan (1978) hypo­

thesizes three "cauldrons" of 25-15 m.y. ages (shown on the figure)

which underwent some of the normal caldera evolutionary steps in­

cluding at least central collapse. Figure l8a presents the cur­

rently recognized stratigraphy and ages of the volcanic phenomena

of the Superstition field. And Figure l8b indicates regional trends

of K/Ar ages of Cenozoic volcanics in Arizona (the breakdown of ba­

salts - silicic rocks here are not based upon the strictest chemical

definition) .

In the Superior area and points north .a'Q-d e~I:?J:~~fr·om it, the

20 m.y. old Apache Leap tuff blankets the landscape. In several areas,

this flow angularly truncates Cenozoic structures, as near Ray where it

unconformably overlies a beveled homocline composed of Whitetail Con­

glomerate. Peterson (1968) suggests that it originally covered in ex­

cess of 1500 mi2

with a volume of about 150 mi3

of dacitic material.

In time it matches with the initiation of the Goldfield cauldron in the

Superstition volcanic field (20-21 m.y., Sheridan~ 1978). Peterson was

not able to confirm a source area for this sheet. On Figure 17, the

Apache Leap tuff forms most of the outcrops of the southeast and east

edge of the Superstition field, and appears to have flowed to the NE

down some paleo-topographic lows coincident with portions of the Salt

River Canyon. Apparently, there has been a post-20 m.y. drainage re-

versal in the Salt River Canyon area, since the river now flows towards

the SW in this same region.

20

In the Northwest corner of the Mesa quad, Cenozoic rocks are found

as a series of basalt-capped mesas which have been dissected by a set

of southerly-flowing streams such as Cave Creek, Tonto Creek and the

lower Verde River. Reconnaissance geologic work suggests at least

three periods of sedimentation and volcanism in the time span 27-11

m.y. separated by variable amounts of tectonism. The last volcanics

of this group are the "Hickey basalts" which have been dated at

several places in central Arizona as 15-11 m.y. in age, and still

cap mesas from the area of Bartlett Reservoir northwestward at least

to the Jerome region. Under the "Hickey basalts" in the NW Mesa quad

are an older set of altered flows of andesite to rhyolite composition

(seen along Cave Creek) and an overlying 500-1000 foot thick set of ba­

salt flows, altered air-fall tuff beds, and minor fluvial conglomerates

and mudstones. These beds were gently folded and erosionally truncated

before they were capped by the Hickey basalts which, in this area, date

at 13-15 m.y. This geology is summarized by Scarborough and Wilt (1979).

No plutons of middle Cenozoic age are known in the Mesa quadrangle.

Rehrig and Heidrick (1976) note that the direction of elongation of "late

Tertiary dikes, veins and elongate stocks" is generally NNW in southern

Arizona (Figure 19), including measurements taken at Klondyke and

Mineral Mountain in the Mesa quad. This indicates, then, a direction of

tension oriented ENE-WSW during their Late Tertiary (22-15 m.y.) interval.

Layered Rocks as young as middle Miocene in the Basin and Range

country can be grouped into domains with a characteristic NW strike

and unidirectional NE or SW dip direction (Figure 20). Rehrig and

Heidrick (1976) explain this regionally based pattern by rotation of

sedimentary blocks along listric faults which represented gravitational

sliding directed towards thermally distended and collapsed crests of

regional NW-SE elongate domes or arches (anticlinal axes of Figure 20)

21

which had formed previously during mid-Tertiary time by "widespread heat

ingress into the crust". Fieldwork continues in areas affected by this

enigmatic phenomena.

Metamorphic Core Complexes

The Mesa quad contains one small outcrop of rocks now generally ~

accepted as belonging to the "metamorphic core complex" assemblage.

These Tertiary phenomena are being increasingly recognized as important

elements of the Cenozoic evolution of the Cordillera (Davis and Coney,

1979; and a GSA memoir, in press). The Mesa quad outcrop ("Tm" of map)

is along the west central edge, and is also the eastern extreme of South

Mountain, just south of Phoenix (Figure 21). This complex, described

by Reynolds and Rehrig (above memoir, in press) is composed of, from

west to east, Precambrian gneiss, a young granite (K/Ar - 19.2 m.y.,

Rb/Sr = 25 m.y.) in the center of the range and a granodiorite (K/Ar =

20.2 m.y., Rb/Sr 25 m.y.) in the eastern two-fifths of the range. The

eastern end of the range contains an upper layer of catac1astica11y deformed

and 1ineated "gneiss" which can be seen to grade downward into undeformed

granodiorite (Figure 21), with the mylonitic rocks now deformed into a

N600 E - elongate dome which has gently dipping NW and SE flanks, and

plunges gently NE. The mylonite fabric runs across the roof of

the range and plunges rather more steeply SW, disappearing into the

Precambrian terrain at the west end of the range. The uppermost levels

of the mylonitic rocks are overprinted by a peneconcordant layer of

chlorite breccia which quickly grades upward into a "dislocation surface,"

upon which, in other areas of Arizona where such relationships are

better defined, some undefined amount of movement of "upper plate" rocks

(a wide assortment of rocks of ages as young as middle Miocene) has

occurred in response to an unknown local stress field. "Upper plate" rocks

related to the South Mountain complex may well include the redbeds ("OM"

22

of map) in the Phoenix-Tempe area. In this model, the listric faults

responsible for the tilting of the "upper plate" rocks gradually merge at

depth with the dislocation surface.

The history of this complex appears as follows: (A) 25 m.y. intrusion

of granodiorite followed by granite; (b) some kind of regiona11y­

based (Figure 21a) thermal and/or stress field which followed these

intrusions and overprinted a catac1astic mylonite fabric on the rocks;

and (c) a warping along NE-SW fold axes, and movement along the dislo­

cation surface, producing a chlorite breccia in the mylonitic rocks

beneath the surface and rotational sliding along listric faults of

the upper plate rocks. Fundamental remaining questions are: (1)

the nature and magnitude of the supposed thermal/stress pulse which

forms the mylonite fabric; (2) the regional tectonic setting of

these complexes, including their relationship to the intrusion of

some two-mica granites which often lurk nearby; and (3) the magnitude

and parent local stress field of the listric faulting event.

Basin and Range Disturbance

The Mesa quadrangle in Arizona is unique in that it encompasses

the southern boundary of the relatively flat-lying Colorado P1ateau-

type sediments in the northeast, and at the other corner expresses the

geology of the southern Basin and Range province. The Transition Zone

(Figure 1) which can be outlined to the northwest in the Wickenburg­

Verde Valley interval loses some coherence as one approaches the Mesa

quadrangle because, this author believes, another zone of relatively

active tectonism, defined by the line of the present San Pedro - Tonto -

Verde - Chino valleys, disrupts the geology and topography of the Transi­

tion Zone. This tectonic zone is that which warps the Hackberry Forma­

tion, already mentioned.

23

Through this complex meeting of differing tectonic styles,

the event referred to by this author as the Basin and Range dis­

turbance can still be discerned. One may confine this event to that

which has blocked out the essence of the present topography of sou­

thern Arizona with its broad flat valleys interrupted by NW elongate

discontinuous mountain ranges. Gathering evidence suggests that this

event is best represented in southern Arizona by a series of NNW trend­

ing high angle faults produced under E-W tension with perhaps a San

Andreas style right-lateral shear component, along which alternating

graben blocks dropped and were subsequently filled with sedimentary

debris, called basin fill. That the graben blocks more actively coll-

apsed than the mountain blocks actively rose during this action is

evidenced by thick marine Late Miocene beds deposited in the grabens

near Yuma, the surface of which is near sea level today, while such

time stratigraphic horizons as the base of the Paloezoic in the isolated

mountain blocks of central Arizona, when joined together into a con­

tinuous surface, defines a gently bowed arch which appears more genetically

related to Laramide-early Tertiary tectonics than to Basin and Range e­

vents. The main pulse of Basin and Range rifting in Arizona appears

bracketed in time between 12 and 6 m.y. See Eberly and Stanley (1978)

for a discussion of SW Arizona Basin and Range tectonic effects.

Basin fill varies lithologically from place to place, ranging from

coarse fanglomerates to fluvial mudstones to claystones to thick accumu­

lation in some of the lower elevation basins of anhydrite (as in the

Picacho basin), gypsum (Safford, lower San Pedro valleys), or halite

(Red Lake near Lake Mead, Luke basin under Glendale). See Peirce

(1976 b) and Scarborough and Peirce (1978) for detailed discussions.

24

In the Mesa quad, the thickest, most extensive basin fill deposits

are in the extreme southeast corner toward Safford, and in the elongate

valley-trough extending through Mesa and Florence. Two deep drill holes

exist which indicate minimum basin fill thickness (Peirce and Scurlock,

1972). The first hole is located in the Paradise Valley midway between

Scottsdale and Cave Creek (T4N, R4E, SW~, Sec 8) and penetrates 4,500

feet of conglomerates, sandstones and minor shales and bentonitic

tuffs, then 80 feet of limestone (fresh water?), and below that 300

feet of dark volcanics dated at 22 m.y. by Eberly and Stanley (1978).

The hole bottomed in "quartz diorite" at 5,400 feet. The second drill

hole, 12 miles southeast of Mesa near Higley (T2S, R6E, SE~ Sec 1)

penetrated 5,600 feet of sandstone, mudstone, thick bedded anhydrite

and claystones beneath 1,000 feet of gravels, and then 2,600 feet of

tuffs and sandstones (Superstition volcanic field?) before hitting

"igneous rock," possibly gabbro at a depth of 9,200 feet. The basin

fill materials here are interpreted to be the 5,600 feet of upper

sediments.

Coincident with Basin and Range faulting, sedimentation in the

basins was proceeding along with backwearing of the mountain fronts

adjacent to the valleys. This mountain front retreat ,back from the

Basin and Range faults has produced a buried bedrock shoulder strip

(pediment) at the edge of most valleys averaging 1-5 miles wide. This

concept must be kept in mind when engaging in exploration for water and

mineral resources. However, the real distribution of these buried, land­

forms must remain speculative in any area until confirmed or denied by

drill-hole and/or geophysical data. See Summer and others(1976) for a

free-air gravity map of Arizona which outlines the deep basins of Arizona.

25

The lower Tonto Basin of the north-central part of the Mesa quad has a

poorly defined origin. It is a member of a set of relatively small NW-SE

elongate valleys in the Transition Zone, but as well it shows up on State

geologic maps as topographically alined with the San Pedro and Dripping Spring

Valleys to the south, and the upper Verde and Chino Valleys to the north.

These valleys, collectively, share certain atypical features such as

Quaternary vertical tectonics and relatively active Pliocene-Recent stream

downcutting histories, and hence are suspect of having tectonic histories

different from most other areas of southern Arizona. Geology of the mountains

adjacent to and thus defining the Tonto Valley consists, to the west in the

Mazatzal Mountains, of Precambrian granite overlain by Mazatzal Quartzite

at elevations above 5000 feet, and, to the east in the Sierra Anchas, a

flat-lying terrain of relatively flat-lying Apache Group sediments over

tilted Older Precambrian sediments with elevation of the contact between

them of about 2500 feet. The Roosevelt Dam region contains an eroded

remnant Apache Group section which in part dips strongly NE. Hence, the

Apache Group is eroded away but most certainly was above 5000 feet to the

west of Tonto Basin, undergoes an east-side-down warping around Roosevelt Dam,

and is found at 2500 foot elevations on the east side of the basin. This

monoclinal (?) structure pervades the geology farther south in the San Pedro

Valley in a very similiar manner, and there, can be modeled as having perhaps

the predominate period of movement involving Oligocene-early Miocene sediments

such as the Hackberry Formation. But in that same area, the structure does

not involve the middle Miocene (14-17 m.y.) Big Dome Formation. Basin

and Range grabens (post 12 m.y.) contain 10-25 mg residual negative gravity

anomalies centered under many southern Arizona valleys, but such anomalies

are missing, or at best of minor magnitude in these alined valleys, such as

the Tonto Basin.

25a

Basin and Range Volcanism

Volcanism in Arizona during Basin and Range times (last 10 m.y.

or so) has been limited in extent. The major eruptive centers in

Arizona are shown on Figure 1, and are associated with the southern

edge of the Colorado Plateau, as well as a few scattered areas in

southern Arizona. Rock types include extensive flood basalts, with

some andesite-rhyolite masses present in the major eruptive centers.

In the Mesa quad, thse volcanics are limited to some mesa-capping

basalt flows in the San Carlos area, and a few flow remnants NW and

NE of Florence. Flows in the San Carlos area consist of higher ele­

vation late Miocene flows and lower elevation flows of Pleistocene

age. See section on Geochemistry for petrological terms. These flows

are intercalated into basin fill sediments and have erupted out of

presently-hidden vent sources. Curiously, the location of Quater­

nary volcanic centers coincides closely with neither a zone of Quater­

nary surface rupturing (Figure 1) nor the distribution of modern seis­

micity in Arizona as measured by seismograph records.

Pleistocene

The last geologic event that has helped to shape the landscape has

been a regional stream downcutting episode which has been most intense

along the major streams of the region. This episode has left paired

terraces perched as far as 400 feet above present river channels. Dating

by paleomagnetic means farther south, near Tucson, suggests that this

episode is less than one million years old. The general Phoenix region

has acted in the near past as sump for materials transported in by the

streams coming from the east, north and $outh,,_where.:te,la(Lvedowncutting

as measured by height of Quaternary terraces above stream level has been

greater than in the western Mesa quad.

26

Globe-Miami Example

Figure 22 is a sketch cross-section through the general Globe-

Miami region illustrating the general geology of that area, except

for the Laramide plutonism and mineralization. Essentially, the only

undeformed materials here is the "QTg," basin fill. The tectonic distur­

bances responsible for tilting of all older rocks (including Tw) are

mostly distributed between Laramide and mid-Tertiary events, as outlined

above.

STRONTIUM ISOTOPE GEOCHEMISTRY OF IGNEOUS ROCKS

The data on strontium isotope initial ratios for central and southern

Arizona are summarized in Figure 23 for individual rock units. Figure 24,

from Livingston (1969) is a Sr isotope evolutionary diagram for central

Arizona Precambrian rocks, upon which other data for Phanerozoic rocks

have been superimposed. Figure 25 is ahistGgram of Sr initial ratios

for some Oligocene and Miocene igneous rocks in the Mesa quad and points

south.

Figure 24 shows that Sr initial ratios for Precambrian rocks appear

to follow a growth curve (line B on the figure) for materials derived

from crustal material having a Rb/Sr ratio of about 0.25 and original

formation age of 1800 m.y. However, as Livingston notes, younger rocks

do not follow this trend, starting apparently with the 1100 m.y. old

diabases, but oscillate in time between line A (growth curve of Sr iso­

tope ratios for mantle-like material with Rb/Sr ratio of 0.21) and some

undefined envelope curve such as Line B.

No Sr isotope data for Triassic-Jurassic volcanics of southern

Arizona are known to this writer. The Williamson Canyon volcanics

(K/Ar ages of 75-80 m.y.) lithologically resemble andesites but by

27

whole rock chemistry more resemble basalts. They have Sr initial

ratios of .7043-.7047. Laramide volcanics of southern Arizona (K/Ar

ages of 70-50 m.y.) in general have Sr initial ratios of .708-.710;

none have been lithologically classified as basalts. Mid-Cenozoic

volcanics (K/Ar ages of 30-13 m.y.) are mostly bracketed in the range

.706-.710, with some silicic units displaying reported ratios of up

to .715. Some of these very silicic, highly potassic volcanics are

known for a variety of Cenozoic volcanics in Arizona. However, none

of these are known to occur in the Mesa quad.

Although data are sparse, a series of two-mica granites,possibly

formed by anatexis of upper crustal material during the time range

50-40 m.y., and which are associated with some of the Arizona meta­

morphic core complexes, apparently have high Sr initial ratios

( .710 and higher? Keith and others, in press). None of these ana­

tectic rocks are found in the Mesa quad. The rocks of Arizona with

K/Ar ages less than about 15 m.y. (with only very few exceptions)

are petrologically basalts with minor rhyolite to andesite differen­

tiates and have Sr initial ratios of .703-.705.

Generally, then, the Sr isotope pattern oscillates between basaltic

events, as with the Basin and Range volcanics, and the masses of Lara­

mide and mid-Tertiary volcanics. The ultimate explanation for the Sr

isotope variation must reside in the mechanism and depth of magma for­

mation and character of source material. However, it is common to

suggest that the high Sr initial ratio materials are derived by par-

tial melting of mantle-crust material just above perhaps a des-

cending slab of ocean lithosphere, while the low Sr initial ratio

28

materials are created at other times where the colder continental

crust is pervaded by deep seated fractures which tap lower crust

to upper mantle materials. This general pattern is quite consistent

with the geology of Arizona as it is presently understood.

POTASH-SILICA RELATIONSHIPS FOR CEN~RAL ARIZONA ROCKS

Figure 27 is a compilation of Arizona igneous rock chemistry by

Stanley B. Keith of the Arizona Bureau of Geology using available

published standard rock data on potash-silica ratios. The figure

shows perhaps as well as any the tendency for igneous rocks formed

during a particular space-time interval to display rather well-defined

chemical variation trends. These trends can, of course, be rationalized

using global tectonic arguments.

If one accepts the tendency of uranium to associate with potassium

in igneous rocks, then Figure 27 assumes some importance in defining po­

tentially favorable uranium-bearing environments. It can be seen that

in general, the more alkaline suites are (1) the younger Precambrian

granites, (2) Jurassic volcanics of southernmost Arizona, and (3)

certain suites within the mid-Tertiary volcanics, particularly some

volumetrically minor high-potash rocks including some "u1trapotassic

trachytes" (Shafiqu11ah and others, 1976). These latter rocks are found

in a SE-NW zone across all of central Arizona with decreasing ages

from 20 to 15 m.y. going from SE to NW. The most studied of these

rocks lie outside the Mesa quad, to the south around Picacho Peak,

and to the west around Wickenburg. To this author's knowledge, none

have been documented in the Mesa quad.

29

The Basin and Range basalts lie at the low-silica apex of

Figure 27. These appear to be alkali-rich relatives of the ocean

ridge tholeiitic basalts, as seen along the East Pacific Rise near

southern Baja California.

The rocks which lie in the subalkaline field of Figure 27 are

the older Precambrian igneous rocks (except perhaps some of the

rhyolitic masses of the central part of the state), the Laramide

volcanics, and some of the early Laramide volcanics. There is data

in Laine (1974) which may allow placement of the uraniferous Laramide

rocks of the Globe-Miami district onto Figure 27.

CURRENT MINING IN THE MESA QUADRANGLE

The main current mining activity in the Mesa quadrangle is a series

of medium-to-large scale copper mines developed in Laramide-aged por­

phyry copper pluton systems. These are Kennecott's Ray Mine, Magma

Copper Company's mine at Superior, Cities Service Company's Copper

Cities and Pinto Valley mines at Miami, Ranchers Exploration and De-

velopment Company's Bluebird mine one mile west of Miami, and

Inspiration Consolidated Copper Company's Thornton pit, Live Oak

pit, and Oxide pit (Globe-Miami district) and Christmas pit/under­

ground operation. 1978 production figures for all operations in

the Mesa quadrangle include 418.5 million pounds of copper, 1.2

million pounds of 50% molybdenum concentrate, 509,000 troy ounces

of silver, and 5,200 troy ounces of gold. Lead, zinc and tungsten

production is negligible. Cumulative production figures show that

about 33% of all copper produced in Arizona porphyry copper deposits

has come from mines in the Mesa quadrangle (16.3 billion pounds com­

pared to the total of 50.3 billion pounds).

30

In the past, the region around the Salt River in Gila County

has been a significant producer of long-fiber asbestos, associated

with serpentine as hydrothermal replacements in Mescal Limestone

by the Precambrian diabase sill intrusions. See Shride (1952).

Shipments by one producer for the past two years have~robably

been less than 1000 short tons per year.

Small quantities of gem-grade peridot have been mined and marketed

by the San Carlos Apache Tribe from a dunite-bearing Quaternary basalt

flow exposed just SW of the town of San Carlos.

Limestone is being quarried at two places in the Mesa quad for

use as a copper smelter flux, near the Hayden smelter, and just east

of the Ray Mine.

Pegrnatites are generally associated with Precambrian granite

terrain of northwestern Arizona, as far east as Phoenix (Jahns, 1952).

However, few are recognized in the Mesa quad. Production minerals

have included feldspar, arnblygonite, spodumene, beryl, bismutute,

muscovite and columbite-tantalite. Production from areas NW of the

Mesa quad is only occasional. Any current production records are

kept only by the U.S. Bureau of Mines.

Lausen and Gardner (1927) and Bailey (1969) summarize mercury

deposits of Arizona. Roughly 95% of Arizona mercury production (7400

flasks of about 8000 flasks total as of 1969) has corne from metamor­

phosed older Precambrian "schistose" metasediments and metavolcanics

of the central Mazatzal Range, where the mercury, as cinnabar, occurs

as veinlets cutting the schistosity or as thin films on fracture planes.

31

As well, some minor amount of cinnabar has been reported from

limonite - cinnabar veins paralleling schistosity in Precambrian

metamorphic rocks from the Squaw Peak area just north of Phoenix,

just off the west edge of the Mesa quad, but production is negli­

gible.

URANIUM EXPLORATION IN THE MESA QUADRANGLE

Potential exploration targets for uranium in the Mesa quadrangle

may be classified into five geologic settings. There is continued

interest in the Dripping Spring Quartzite member of the Apache Group

in areas east of Roosevelt Lake in the Sierra Ancha Mountains, and

some current drilling in this area is being done by Wyoming Minerals.

Much literature exists for this potential target, and is summarized

by Granger and Raup (1969), and Schwartz (1978). The uranium here

appears stratabound in certain units of the Dripping Spring Quart­

zite, but apparently localized near diabase intrusive masses. It is

not obvious whether the uranium is related to the diabase intrusives

or whether it was deposited along with the clastic sediments.

Uraniferous horizons consisting of channel-fill conglomerates

with carbonaceous plant trash are described in beds of the upper Naco

Formation and lower Supai Formation along generally the southern boundary

of the Colorado Plateau in central Arizona by Peirce and others (1977).

Figure 26 indicates the "zone of interest" in an area along the Mogollon

Rim and south from it, generally between Payson and the westward limit

of the White Mountain volcanic field. This mineralization is thought

to be related to diagenesis of the sediments and Paleozoic in age.

These authors suggest that small targets at near-surface conditions

may exist near the contact between the Naco and Supai Formations in

the extreme NE corner of the Mesa quad (PPn and PPs contact on the map).

32

Several copper-bearing pluton systems in the State are known

to have some associated uranium, such as the Twin Buttes mine of

Anamax south of Tucson, portions of Phelps Dodge's mines at Bisbee

and Morenci, and portions of the Pinto Valley (Castle Dome) and

Copper Cities mines belonging to Cities Service Company in the

Globe-Miami district. All these deposits are Laramide in age ex-

cept for the Bisbee deposit which is thought to be Jurassic (180 m.y.).

Uranium in the Copper Cities and Pinto Valley copper systems was the

subject of Still's (1962) PhD thesis, who noted that the uranium dis­

tribution in the pluton systems there closely parallels that of hypo­

gene copper insofar as both show a "vertical hypogene zoning and both

are slightly concentrated along a granite porphyry - quartz monzonite

contact." He notes also that "the Copper Cities deposit contains an

average of 11 times, and up to a maximum of 38 times .......... , the

quantity of uranium that usually occurs in normal igneous rocks of

this general composition." Uranium recovery is now being engineered

or attempted at tailings at Twin Buttes and Bisbee, and in leach

solutions at Morenci. To this author's knowledge, no uranium is cur­

rently being extracted from any deposits of this nature in the Mesa

quadrangle.

Some limited exploratory drilling has taken place in basin fill

sediments occurring in various parts of the state, including the Big

Sandy Valley around Wikieup and the Lake Pleasant area just north of

Phoenix. In the Mesa quadrangle, some drilling has just been completed

in the Tonto Basin north of Roosevelt Lake, with unknown results.

Thus far, however, uranium found in sediments of this age group has

proven to be only locally and subeconomically concentrated. This is

not surprising in light of the sparcity of seemingly favorable host

33

sediments or environments to act as concentrates of uranium. A re­

cent report by Texas Instruments, Inc. deals with aerial radioactivity

traverses through roughly the SE third of the Mesa quad, and lists

110 "possible uranium prospects" in the quad, including some basin

fill-aged marls just SE from San Carlos.

The last recognized potential uranium source rock for the Mesa

quad is contained in a series of lower to middle Miocene floodplain,

paludal, lacustrine sediments which outcrop discontinuously through-

out central and west-central Arizona (Scarborough and Wilt, 1979).

See Figure 2S. There are many uraniferous outcrops known for these

sediments in the state, and the Anderson mine of westermost Yavapai

county owned by Minerals Exploration Company and Urangesellschaft

USA is the foremost of these, having uranium reserves probably in

excess of 20 million pounds of U3

0S

' and potential uranium resources

of 60 million pounds. The uranium here is bound to black carbonaceous

and silica-bearing paludal(?) sediments. Sediments of this age are

found in the northwestern Mesa quad as noted in the geology section

but here are light-colored tuffs, marls, limestones and mudstones and

are only known to contain isolated and low grade uranium occurrences.

However, the full uranium potential for these sediments in the Mesa

quad (or elsewhere) is unknown since they occupy the hills under the

"Tbo" cover basalts of several parts of the NW Mesa quad. Near the

town of New River, 5 miles west of the Mesa quad, preliminary drillings

by the Univex Mining Company has uncovered a potential uranium reserve

in some sediments of this age near the surface of a small valley. Here,

no carbonaceous sediments are known; rather, the uranium is associated

with a series of thin dolomite beds which outcrop at the surface in places.

34

REGIONAL CROSS SECTIONS

Included with the map are ~ight regional cross sections drawn by

Mr. Carl B. Richardson of Tucson, Arizona. The cross sections are drawn

parallel to each other, oriented generally N 600 E, and have a horzontal

scale of 4 miles per inch, a vertical scale of 2000 feet per inch, and a

vertical exaggeration of about ten to one. Their general orientation is

shown in the figure on the following page. Numbers on this index figure

refer to circled numbers found on the individual cross sections. In each

case except 53 and 54, they cover the entire Mesa quadrangle. Geology on

the cross sections coincide with that on the enclosed 1:250,000 scale map

only insofar as the state and county geologic maps served as starting

points for the cross sections, and some differences in interpretations are

to be expected.

35

\

36

F'1IAre. 1. rhysiofll.fhi<:. Pr()vjYl'~S dna post JD m.y. voLc~n;' ro~S: in AriJoncl..

»1'lS<L ~~"'Ar"'t'l11~

1

' . ••••••••

,

4

""\ 3

" \ '\

'- o-l)- m.y· olc\ vol.c.o.V"\SM

~ 4'" 1 »'I.y. olJ vclc.~W\ism

........ »1 e1 1DJlO Y\ ~S'-A."fW\~~ (sou1'~~r1\. • bo"V\~"r y of (oll'rA!o fJ~t~o.0

--""" "''''' ....... !)()lA.th~(Y\ YI1~r,;V\ Df tr4"Srrl~ . 30')'\ <t.

37

Desig>atian on

Arizona BureC>J 01 Mines

CC>I..rty GeoloQic Maps

Oiabase (db)

Sandstone and quartzite (u)

Apache group (Au)

Mescal limestone (Am)

Lower Apache group

(Aq)

Granite ond related crystalline rocks (gr),

diorite porphyry (di), pyroxenile (py), and granite gneiss (gn)

Mozolzal quorlzil. (mq)

CENTRAL ARIZONA

Grand Canyon Disturbance with Intrusion by diabase dikes t sllls, and irregular bodies

Sandstone and Quartzite i Troy Quartzite

Thickness in teet

north cnd northwest of Coolidge Dam 0 - 1,250 (Figure n ~ ~ --UNCONFORMITY ~I- - - -

Apache group

Basalt Mescol limestone Dripping Spring quortzite Bornes conQlomerote Pioneer shole Seen Ion conglomerat.

Toto I (loco I maximum)

0-375 225-500 400-680

0-40 150 -500

0·20 1,600

SOUTHERN MJO SOUTHEASTERN

ARIZONA

Grand Canyon Disturbance with intrusion by diobase

lower portion of the Troy quartzite between latltudts 32·30' end 33'30', opproximetely (Figur. 7)

UNCONFORMITY

Apache group

l"Thi':l(neSS in feet I---

80010 1,500

G REA T UNCONFORMITY

Mazotzal Revolution, culminatin; with intrusions rongino

frem Gronitic to 90bbroic in composition

Malatzal Quartzite I Maverick shole, end Deodmon quorlzile 5,400

~-----------------+~r~~~~------FAUlT

~Id.r group: Foliated

volcanics cnd slole Schisl(SCh), rhyoille (rhy),

ond 9reenslone (9$1) """1.

v<.>

Red Rock rhYOlile: ~ 1,000. feel ~

FAULT ------'1 A sh Creek group:

20,000 10

30,000

Pmal schist:

Metamorphosed sedimentary cnd

volcanic rocks 20,000

Basaltic, ondesitic1 rhyolitic, ond li doc:itic flows and pyroclastic rocks and luffac.aus sedimenlory rocks. 20~OOO 10 Locally folioled. £3,500

Tolol Yavopoi 41,000 to 54000

~-G-ra-n-il-e-g-n-e-i'-S-(-g-n-) -t-'------G-ron~.-9-ne-i.-s----...I-.:::c:==+----G-r-onit: 9nei

ss i

Tentative correlation of Arizona Precambrian units.

FIG. 2.. General stratigraphic relations of the Precambrian rocks of central and southeastern Arizona. (Reproduced from Wilson, 1962, by permission of the Director of the Arizona Bureau of Mines.)

.frOM L'\)iY\~s1'oY\ ~nA D~",oY\ ("~i).

38

Trio.ssic..

PurniafL

F" tAr~ 2~. s~1c.." 1"e>Lo1i Co

A"A, sCI41'hut\ Ari)tM, .

39

, T roy Quartzite ~ , , ,

Predominantly light-colored quartzite and sandstone; conglomerate horizons; cross­stratified.

UNCONFORMITY

Vesicular basaltic lava. not everywhere present

1iAlf~"=!:'~""," Upper member: 0-110 feet; cherty and novaculitic siltstone and shaly mudstone; thin-bedded; predominantly red to brown.

Basalt (less than 52 feet) ..... ,....... ....... ¥-"~:-..Algal member: 10-150 feet massive dolo,­

Dripping Spring Quartzite (323-708)

..... ...... . ............. ............. , ............... . .............

Pioneer Formation (150-400 + feet)

... p'''-

':·'\;;'./:t~~.: I ..... . Scanlan Conglomerate .......... "

(0-155 feet Av <25 feet){ Basement Rocks ~ , , ,

I,

" " : I

mitic limestone containing algal struc­tures.

lower member: 150-269 feet; thin-bed­ded impure limestone and dolomite; intercalated chert layers.

E:ROSIONAL DISCONFORMITY ---~

Upper member: 180-397 feet; predomi­nantly siltstone. gray to orange-red thinly stratified slabby to flaggy; feldspathic sandstone more common near top.

Middle member: 0-370 feet; very fine grained to medium.grained feldspathic to arkosic sandstone and orthoquartzite. reddish orange to grayish pink. cross-stratified. slabby to massive .

Barnes Conglomerate Member: 0-50 feet: well rounded quartzose pebbles and cob­bles in arkosic sandstone or quartzite

r' E:ROSIONAL ISCONFORMITY

. Predominantly maroon to purple tuff and pink to gray siltstone a'ld sandstone; arkosic and quartzitic at bottom.

ubangular to well-rounded quartzose peb­bles and cobbles in a largely arkosic matrix.

UNCONFORMITY Metasedimentary and metavolcanic rocks

intruded by j!ranite

-I"I---'o"""..,."",~r E:ROSlONAL DISCONFORMITY -3?x:f.::E::~ Whlt~ urut 0·12" feet. siltstone, thlnl)' .nd Ivenly stratified. I'Bh(- to dlrk-,t.),

" '~""-WtH" ,">.I,rUI!e ml,!..r: 0.14 feet; orthOQu.'~ll" .nd unds.tone, qUlrtzose to ,.Id· II:'" "';-;1 ".,0". ,'"" ,. '.""'J."n.d, ,.d" ' •• m'nJ

Bufl un,1 41-168 leel. s'ndstone, feldipathlc to .rhOSIC, 111M-colored, very fine C'3,I,.'(I t" '''It'·&rAmed, .bundanU), cro$s·ltr.t.f.ed, 5tyolitC'$

Bla, ~ lot .. ",!, \3-12(1 leet, ,.Ustone, .rkosic, CI.rk·lfAy. lIaggy, thlllly lind i"eaulJH1y ~"ol" "f-d c'umVl"d ~tl"nka&e crack,

M.Odlt' ,.,C'mDe. J~3f,9 leet $.nd$ton •• nd orthoQuillfll,te. QuArllosC' IltAf 'qp

C(1"iil,""f'.a\lc and arkos,C near base: ,reyj$h pink near top, mortelate red nt'a' ... '~f' ""V f,ne gf.'''H~·d to COo1rs..'li:f •• ned; $'abby to maS$I\(i!. ('Oss·~lfaur'el.l

£R0510NAL DJSCONFORMITY

Flou .. 3--GeneraUzed columnar lIection of tbe Apache GrouP. Gila County, Ariz.

1rD~ GrAY\1tr ~~A ~~"f ('~b¥).

40

fi'IAY~ 4. Prt.s,lY\1Lr k~OWh O&A..t(.rofs (J,'~c.k '"0100 4:\Ytl L,·~;ts of d~f0.s/t,.~ ~-",,) of 1t1UMi4l. ... Pr4lCAMbrj4n Ar~c.k", Cs-rolAf St.A. lM,.,1s i" sov.th~r" Ari) MOw , a.~A. .,.At<..rof~

or fossi~1y ~\"iv~Lt.~t U"k.r ~rolAf '" r\oft~ .. rt\ Ar")'MtJ.... ;~ tM Gv A \'\1. ( .. ~ 1111A. ·

41

Mescal Aztec

10 0 10 20 30 MILES I""", .. ! I ! 1

o 3000 FEET 1""ll!I!!·II!.1

HORIZONTAL SCALE VERTICAL SCALE f i,ur~ 51:>. -North-south geologic section at the end ot,Devonian time_ Structures are diagrammatic, hut the positions ot theTroy Quartzite and the Apache Group relative to tho pre-Bolsa and pre-Martin uncontormltl ... are probably

rtfr(""i.rtlu~,

Oraioon /nta,n.

Little Drasoon Mounbln.

Holy Joe Peak

Me.cal Mountain.

Apache Mountains

Aztec Pe.k

Christopher MOiollon

I I Winkelman

I I Globe

I I I Younlr

I Mountaln_ Rim

" . '.".: Quartzite member ofT~oy: .. :.'.: ... :. .:, ..... :: ... : . , . QUartzite member of Troy

~ .. \~:"T""_\l--:"\"":..\I_t"'\/~/~:::'I· . ..I/\/~~~'~ 0i'I::-I:::\~r:;. 1"1\...- ~~~\/'""':.',''::;~-r"-\i \ ........ \I/\-,I~/~/_"'\(.\/~/':::I;I; I~/'''' ... ~ ~:::;. '":..':(.\"!./ .... .. J_.... :...-=-~ .. ~.J\- /.:. /~/_\~-\ ... ;~/ -';~j\/_~/}J:: I~/--..I~I/ 1_~--;;:;:-Pi2n~ti.ie~:=.:-:·.:::;:. !\~I~I.:-;/ '-I~'d": :I/\'....\'...! .. - -:" '; 1-' .... ~~I ~\-I ,~;t~;5IS,?F5:)\",~/~/~-~7:~}·'~/~/~; .. ,~~9~1,~.: -; ~!2/_~1~e~~~e~.mb~li~·~r!'}.t!:n7~~:51~ ;~/ ... '0~/(;'(d;:.,~,)/;,~I~ ~~7~1~;~~~;~~(.::~};~~~:.; ';i\::,-:.(\~/)~'L\~I~~ ;-;':-~ ?_\~~..!/~;/~;; 1~\?\~\~\'(1;"\/\/~:7~ <.1 I !~! < I~/~ I:: I::', ~I::' {)",- I~I ~";'\("I;~ ~\~I/ ~-~~-; ~,'I~,\-";'t;-'~~ ;(,1; \,.<';./!~II~ \::: :;~ ~\ -:-~-:. ~I'

.l>­N

if I ! , tit I , ,9 if 210 3p MILES ? 1 ! ! , I ! , , ! I , , ,3,OPO

FEET

HORIZONTAL SCALE VERTICAL SCALE

.fi',l.Ir-t 5 Cl.. -North-south geologic section after the Troy Quartzite was depoalted. Vertical ex:nggerntion overemphasizes pre-Troy folding and angularity between Troy and Apache strata, Contacts dashed where there are no remnants to confirm Interpretatlon_

both from Shri'\~ (t167)

33'

32'

112'

t

f I

1 Y A V A P A

---

\ \

"-

" !? ; ~. \, '\7 .' ii

--------- -......- - --~.

-Diabase Principal outcrops only

Troy Quartzite and Apache Group

EXPLANATION

IHJ

"'-"

Quadrangles in which younger Precambrian formations have been or are being studied

DB, Diamond Butte McF, McFadden Peak BH, Blue House Mountain RM, Rockinstraw Mountain HC, Haunted Canyon

I. Inspiration G, Globe

S, Superior R,Ray C, Christmas

HJ, Holy Joe Peak M,Mammoth 0, Dragoon

M A

N A V A J

" c~<1-' ..... ),. r - Southern limIt of Colorado Plateau structure

I

I

~~~-----

\\ . c 0 CHI S E

I, \. \ i ) ~ :~@

\ 0

10 0 10 20 30 40 MILES LI U' '-'.'.1...' 'u'.!.' w' ,-ll ___ -'I ___ -LI ___ .LI ___ I

FIGURE 6-0utcrops of younger Precambrian strata and coextensive diabase intrusions in southeastern Arizona, Modified from county geologic maps published by Arizona Bureau of Mines, 1958-60,

froVI' Shr',d It. (I" 7) .

43

,.,

,,'

,..

Figure 7. Total Paleozoic isopach map and index to thicknes s sections shown in Figure e.

from f~lho\(I'lb~.

44

~ 1I1

Cf) <1l <1l

'-.:J

<0 C .... <1l'-.:J

-1$ _c o .... .... <1l

00 .... . m...., ;;':r OI~ ... 0 ~ "" o ::l ::l <1l

Ul Ul

"0 "1 o ~ m Ul

o ...., ... :r <1l

"t1 01

m o N o n-Ul ... .... ~ 01

o ..., ~ N o ::l 01

BLACK MESA BASIN °m~~~G

O.t/~~~~F~ASH , __ -COCONINO PLATEAU --t -- -- - ;- - -=-B~~~K -M~;--= _~r-:-DEFIANcq Pk Pdc

1000

2000

3000

4000

5000

6000

7000

P Pc ...............

P. ----- ----

pC

OAK CREEK y/ Holbrook "Anticline"

o ......... /... . .. . Pc Pk

1000

2000

3000

Pou

Psi

-~--~----------:: '- 0

C pC

SE ARIZONA G Gila River

0'

1000 P

MOQolion Rim

Fr. DEFIANCE FOUR CORNERS

F , rO

1000

2000

3000

4000

P Holbrook "Anticline"

D Fr. DEFIANCE

PC -.Q ..•...

Psu .......

2000 ----- ..... ---------------- Psi ,-,,1(. .... 3000

4000

6000

7000

-----pC

!' -- ..... _--

50 0 50~1" I I r

P - PERMIAN Pk - Koibob Fm

Pc - Coconino ss.

PQ - Glorieto 15.

Pdc- DeChelly !I.

Psu- Upper Supol Fm.

fa - Fort Apache Mb .

Psi - Lower Supai Fm

P - PENNSYLVANIAN M - MISSISSIPPIAN

D - DEVONIAN

0- ORDOVICIAN

C - CAMBRIAN

CONTACTS Mojor hiotU5.

No siQnificant hiatus.

Permion formations.

Figure 5. Generalized isopach of the Permian System.

frc>~ PIt\rc..,- Q.,7b ,.,].

46

-P--..J

(Cr<:.to..<.<zous ~s\ ~ ~oc-<;;Ol> J

Ko..·,bo..b L; VI'\R. ~ t 0"(1 -.

Co <:..o ..... j ... o S~ .... ~",14M,"

~LOfll~\~'<. ~ Q LL- sLtst "'bf I(rm

t;:L'"i:,,-;. [l."-'~-"'~~-'-~L""S-J -

<­sr.- sl"tst .... \, .. Q.

6.pp r-oxi ~4tlt. T~IC.lcMS.S.'-S. ) f~t

(H",\IA't b>bf. :l 1- III

L<;- ss "')>"1"" ... r--------L....JL.l

1000

100

o

~1I1!.1 No..c..o

"'PP"r

Dev. """b..\\-<t ,5 ~

L ....... r ., ~

C(un. To.p<ac.Ts

f6.

(I)

r"ur~ ID. No~~~(.L4.t"f~ 6tM~ 6.ffr-oX'tWlAt.t... thic.kttt~s(S ()~ PaLvJJo i(. rlYQ,t~ i" t~ Y\\\S~ t IAttl.. ro.'f\,\I(".

L 1~'S'D"I\'l, ShALQ. J

YI'I~.\ s.'t '"' t. S

LIVM.s1cm~

SlAY'Ij..., aolo~\tts, S~d.\u

SCIM~~tOl\U

vol(.o~i(~J pL\.\rt>l'1t<..~

Dr1fflV", Sfi'1l1

® /"---

r' iiJ "' rHOE.NI~ IMcS~ __ ':: __ ...I

(/~~\ \... __ /

A,-:!o

CLIfTON

SILVER (Ii,/

(c "f'li<l.<'Q..C)\'( s) \ "''l~~:~'''~llo

HOftV,'\lLa.

rr~c .... """ bt"I"lI.

4ro.v\i\~

@

.c E

MESA QUAD .<:: z

4) ,&.J wO ~ 0 -'0lf) t) _ e 1-l!:>1- "

[== ____________________________________ ~~~ ______________________ ~ ____________ ~=~E ______________ ~~~~~~ ______________ ~~ ::e ...10

<Xl C

MAR T N FOR MAT

UQpe r. membe r.·.·.·.·.

Ab r I iO

Isa Qtzile

. Qua r lii'l e ....... .

HORIZONTAL DISTANCE APPROXIMATELY 150 MILES

VERTI CAL INTERVAL APPROXIMATELY 3000 FEET

o N

Formal ion

Figure 11- Stratigraphic relations between the Sierra Aneha and Bisbee, Arizona

-fro W\ Kri", .... r. q~~,,) AriJ ~ G-... L. $0(,. ~~\~\.~ootc..:lZI.

48

'" c ~ ., o c .. .c E .. t.)

r---i If-----

72' 17'

t---28'

Mar tin

--.:-: .... ~ .. :~ . -.-' -.-'.- .

-'-.-' .. -. -.-' '-:-.'-.. -..:...-. . -'-'.- -'-:-., -'.-'-'-'~

.. ~ .. ·.~·O:~: .. '.' ... ·.Naea· . "0'" . ~'-'-'-'-.. -.-.-.... ~: ... ... .

--,'--~-' -'-o-r'm a o n _._._._ . ...:,

.. " . --.-:~ .... ::< :' ~ ..... ..

~ .. 'V.-'-' . -.-. --- -

formation

~<~------------------------------------600'± ___ ---------------------------~~------~>

Rubble brf'CC1Q of limestone solution blocks ond residual moteriol

EXPLANATION

Ctll~rl1 limn tone Slump blocl\ limestOne

}'1Gun£ 12. .-Sketch showln&' the contact ot the Redwal1l1mestone and the Naco tormatlon near the confiuence ot Horton and Tonto Creeks, Gila

County, Ariz. (iocallty 13, fig. 9). ~roW\ "",AA\ ~ A~ D.b r.vol n 1 ("sz).

49

o 200 I I', II I

200 400 Kilometres

EXPLANATION

Jurassic evaporite basins

.,. --- .. _ ..... -- .. Proposed extension of Jurassic evaporite basins beneath overthrust plate

Leading edge of Laramide fold - thrust belt

Movement direction af overthrust plate in Laramide time

Anticline or arch

DUtil. r1 ~ rIA 51 f i 9L-trCf.. 11. -rk-. L4 r9e. LArA ..,', ~ ...

b~Lts t-r tht AmtriLaY\ l:or~~IIt.'ct..... AnA -:r&.tr'~~S·'C

(.\)~forit~ ,l,4$;ns. IM.\LH.sit·oYl bJt(..om,"s t»h4..1h\.y or \'tot -t~~s~ 1'hrlot,i btL1s o.rt.. fr\.st.~l i ... ~,,,,1~\rt'\..­

Ar\JCMA...J p.trh",~ it" tht sv.bsurf' ... Lt..

50

33°00'

PED-6-70

• D ~

fa

Sample location.

Post- Laramide volcanic Cover.

Laramide d I k es bodi e s.

Laramide stocks

Belts of Laramide Intrusive rocks in SE Arizona

E. A. Schmidt, 1970

sedimentary and

and i"trus i ve

and plutons.

~~A. rVOW\ S,-t.,m\at (1470) PhD) Univ. orAr;3cm~. LA ... e>.W'\A~ pLlA.-toYls I'V\ ikR. 1lnlr~L Ht:tyekM.­

~rq"Q... j So lAihltr~ Wh.s 4A...l u.q! • 51

,... "" .r-rl~~------~I~ __________ '~r __________ ~'IP __________ -l'r __________ ,~)~

o --

,I..

SCALE .. WILES

<,,,;1 26~

DOS CABEZAS 131

Figure 15. Strike-histogram rosettes for Laramide dikes I elon­gate stocks I and ve ins (in that order of abundance) 0 Rosette bars are constructed for 100 strike segments of bearing angle from NS to EWo Lengths of strike bars are proportional to percentages of total strike measurements 0 The total measurements are shown by numbers beneath each plot 0

52

t-'"

lJ1 W

rl!l

i ~

I ~ 11

20

10

Number of K-Ar Dates

n I

~

~ Basalts

n n

!

O V«««<;«{««1 it&! I ~ I i '

~ 10 20 30 40 50 60 70 fl K-Ar Age (m.y.) ,] '1 II Figure lb. Histogram of late Creuceous-Cenozoic K-Ar dates for hypabyssal Ii plutons and volcanic rocks of the Basin and Range Province. "I I'

~ from Eo..stwooc\-, ~.(1~70 UYllv.ofAr;Jtm~ uhpub. fhDt"~si~ W

F.,u,:e..17. - .'Distribution of volcanic rock . . slitIon-Superior field S . . s associated wIIh the Super-

(G)' . uperstItlOn cauldron (S) G Idfi

• and Tortilla caldera (T) ar . d' . : 0 leld cauldron e In Icated by the Ime pattern.

60,70 eo ••• ----~

I!IllllIllI Tortilla Caldera < 15m.y.

~ Goldfield Caldera 15-16 m.y.

§ Superstition Caldera 25 m.y,

10,89

60,70

F"~~eJ8. Detail of the three principal cauldrons. Main faults shown with the ball on the down-dropped side.

fi'turc. 5 iLL ... ,"tr~; .. \ .. -;:\' .. h'\' .f S"ftt(ti'tl:'" "blu,:,(. f~ .. LA I 6.V\~ 'f;th"S'I)"'~ r.u~\ts .i -th~ -throlQ. c.-."LA. r.f\S 't-toS"'~ \>)' Shat\\~""·

54

Age (m •• )

15.2 + 1.0

16.1±1.0

16.3 + 0.5

18.4 + 0.5

17.8 + 3.1

21.3 + 1.0

24.4 + 0.7·

29.0 + 0,6

Oligocene?

1395 ± 45 1540 + 84

Thickness (m)

200

lO- IS

o - 270

20 - 170

o - 100

o - 200

15 - 25

30 - 430

20 - 100

10 - 15

o - 100

o - 670

330 - 450

Unit

Canyon Lake member of the Superstition Fm. Rhyolite and rhyodacite domes and lavas Geronimo Head Fm. ash flows and lahars

Dogie Spring member of the Superstition Fm.

Basanite

Geronimo Head Formation ash flows and lahars

Rhyodacite domes and

Basalt

Geronimo Head Formation ash flows and lahars

- -S~p~o~ : : Draw

-member -of the

5'tQ.. 5tka.lus Q.~~ S~'trIAo.l\ 0110#

- Supers d don - -Formation-

Latite of Government Well

40 Older Basalt

75 Arkosic conglomerate

- - - - - - Granitic basement - - -

Figure 18,.. Idealized stratigraphic section for the Superstition Mountain region. Diagram from Stuckless (1971); rock unit ages determined by Damon (1969), Stuck1ess (1971), Stuck1ess and Sheridan (1971), and Stuckless and Naeser (1972).

55

40

30

20

10

0

30

20

III C 0 .--0 c E ~ CI) -CI) 30

C ~ 20 c:t I ~

--0

~

CI)

~

E :l Z 30

20

10

BASALTS

20 30

30

20 30

SILICIC ROCKS

Platea u

Central Mountains

ClrF:L o 10 20 30 40

Sonoran Desert Region

o

Eastern Mountains Region

o 10

K-Ar Age

40

Figure 4. Histograms showing K-Ar ages of volcanic rocks from various physiographic regions of Arizona. Histograms based on both published data from literature and unpublished data from Laboratory of Isotope Geochemistry. Data for sam­ples from the Arizona Strip are not included in the histograms.

u.· "'t V-f----;r----"~~~:,...-.~~~'"'_"_"_'

il

1 . 1 ., , ! I

J

Figure 7. Physiography of Arizona. Mountains and basins are represented by darker and lighter shades, respectively.

fi,t.V\J... 181,. ~At'lot\",L Ir.u,\As ~f k/Ar Jo.t~s in Ar;:s tmo.... tor (1t)l\0Jo i, ",n~ous roas. Tro", Sh~ fi b "LLAkJ ott (l L. (191 S).

56

m~.'~-l" -'"

I .: -.0

,,~ CASTLE DOME 117

21%:

"'~ ---- . , ,Q- •

__ O'tli,eltenbur;

VULTURE 'Mrs 4'3

.),.

SCALE

" MILES

. /~~

13"i.~. DOS CABEZAS Mrs

3B2

-~ _. '

I ",.

froWl R~hrii ~l Ht'Ar,'<.k (l11b) Figure '9. Strike-histogram rosette plots for late Tertiary dikes,

veins, and elongate stocks. Some mid-Tertiary (>30 m.y.) data are in­cluded in the Dos Cabezas plot. Rosette bars are constructed for 100

strike segments of bearing angle from N S to EW. Lengths of strike bars are proportional to percentages of total strike measurements. Total mea­surements are shown by num::,ers beneath each plot.

57

r-____________________ ~U~TA~H~ _______________________ _.

EXPLANATION

~~T='~~I~ ~ tUTlAl'll' fM-.- ~ 1.&.1 011.--) A.

Z

..-( ,nUKE AND D.I' DIII::[CTION

HQIIIIIOtf"TAL TO • IUI-HCWIIZONTAL

1(001'"

'\

.,MIOXlIllATt AlIII Of -':"()/I(4l1JtQ4 AHOlOfl:e~

ITfhJCTUM:

.flAGSUFF

Figure 2.0. Attitudes of tilted, late Oligocene to Miocene vol­canic rocks in the Basin and Range portion of Arizona. Two major arch­like structures are defined. Central or crestal segments are preserved in certain areas (see text); However, elsewhere the position of crest axis is approximate and inferred. Map's construction is based on data from county geologic maps, Cooley's tectonic map of Arizona, and the authors' own field observations. In a few cases, attitudes on pre-vol­canic conglomerate s were used.

58

PLATEAtJ

59

fJ', urI(. 21". h1~:tAmorfh;l. I

CD Y l c.o ton f J Q..:1-~.s H'\

Ari5(M~ ~ bl-.Lk) tha.1 t\r~ fr~StntLr r\(Dit1i3~a •

• ~or~ c:.o~~L,-~~.s '

f,', t.tr~ 21 b. Hypothtt'<'4L Cross - Se.~ tio)1. or "fF- r ,or~ (;..(;)vt\p{t...x ro<..~s. -r~

h11 LOVl'lt~ a.t Sout~ W)oLl.,tdtr'n (O'YI-tc: U1 S w~l\ - a~v\Lof.t..~ CQ.-r~(.LQs1j~ L"lnl~tl~ £)ri~.1t~A tv 6(/6 i~ Mosto.,(,Q..~s.

ALL aj4 tt"o)tt ~9.1t1DL~s

4lM1 ~hr;1 ~h fr"~$/ GSA

~h.mo ir Dr! (or~'1 \\ .. r~

"'" iO.Vllor f h " ( /:or (. c.o"p I t ~0 .

Qt

\ \

EXPLANATION Alluvium, Qal; talus, Qt; basalt, QTb; Gila conglomerate, QTg; dacite, Td;

Whitetail conglomerate, Tw; diabase, db; Naco limestone, Pn; Escabrosa limestone, Me; Martin limestone, Dm; Troy quartzite, (:t; basalt, p{:b; Mescal limestone, p{:m; Dripping Spring quartzite, Barnes conglomerate at the base, p{:ds; Pioneer formation, Scanlan conglomerate at the base, p{:ps; Ruin granite, p{:rg; and Pinal schist, p{:pi

\

"

\ \

" " \ p{:pi

\

FIGtlllE 3.-Dlagram showing the hypothetical general relationships ot the sedimentary and volcanic rocks and the !ntrude<1 <1lubase.

Gtolo.c...- Yrt',,,wd 6.\str;c::..l'. 1roW\ plt.t'rso~ ~,,,2.» r·7.

Aff ... n,y\tLy, both Pfc,(.Q,lIIbr;(\l'\ o.l\6. L"fA.Wl.i!t. .. Q,,~a !i-.b"u.s 6.r~ r(,~S~'t'\-t i", this 'Wto.. ~itl(.'i. P .. L~cjo·li.. has carq .. Ais rL.tft~ci) j ~ow~"'~r, trnl'j

1'h~ Pr~c~Wt~rio." 1t.\)~~1' k6.~ bll..~Y\, ('cMrirWjQ..l b'f o..,-t d~l'iVl'.

lo.t"<:.r ~lIt-t: rc.rsav\tl. c..ow.",ul'li~Qil~ froWl S.B. JW.th .51A.,jl!.s1"-s tw-tlUl. J,.lQ,Io«s-t... - fQL~cy:li<. C:CN\i~ct Q.bouQ.. is 0. fQ,\A.L..tll.J.. CIII'l.. ~\'I1. i'l"l fQ.(.t th~ ~bQ,s.tt. is fr~c::.o.~bri(H\.. H-t~c..ct no r05r- ~/~o)oi~ clio.hQ~""" is <:onfjrm~cl in th.... G-{ok- ~I· ... ~i t1,'stri<.t.

60

\

\

t="il..\(~ 23" 5~ a~~ tM. Sr JSQlt>r/c: ',YI"lt,'Al r..,..t{os for c~y;tr'L. ~c\. So ""t~'tr~ Afi3 fMo... DA."tea.. rvqW\ Da.m C'M, )~t. oI\L.;I '1" If -/1'70 (.ttl";!!. to A.E..<.. ~ fk 0 1'~~s~s ~1 8id~IJ)Wl~V\1 t .. d~o.c&. J OMA Livi~1siu~J nt.S.-th~~ (S by I\rc;1'> ",,$ j C\~~ fIC\P~,(s by S1'"",kL4.sS A'A). o'NlI.\L(li13) ~).. It\'\6orbo:t'' cc.:t~.( \9hl ).

m~ m~ f~ comf~ri~1'r\. oc.&t~t\ riA,t fh.,L~lit~$ (ft,.t:.fl..v.-.-rlf.c(nf)

L~ e...cM1',.~-tA1 Grt.\.si

~V"lfA'.t. c...cy,t\Y\.II.M~ c..rM.~t

Prll. C,Q..W\hr;4t'\ rOG.ks .... "emil

Vvt ~J.ctr~ J. \(.1rit~ o~ ~''''$~I PI~Q.L ))')11\1-lilO my

~4A.t" 6-r,,~lf'l I~~O ± 2.5" WI.y.

r~oo Why- oL.! d. \ .. betSoClS

1100 ~,Y' old )..~''''.tt..s R~WloYla fm. ,S-IO ffl-Y· (stJj ~t~ (~~ tw.i~r~roLi1~ l'" fln~L sc:J,. i1t ;ortlll" mth~,

()t1~ I' ~o w.,y.ofIY

'Y't\nitf~ rtJ ,ks J so&o\1h'trh n1~41'J~ mtlts. S~lt ~"i~r arolo.. J 163.0 ± "10 vn'l' to ",r f.tt~1::.s o.r~o.. J 1110':!:. bO 1ft. y-

Lqro.~,ao.. yc(..ks Gv~., ',tet »1014 ntot&l'~ f"f ph Y" 1 (R~y) fI4,"/)d~se.. Ltt~t"'tflil>ooA. ~lA~r13 Atoritt./ SA h"t4 (A1AL,~,.t

.101 - .701 mohrn 1 .7027

_7olS:­.70$"0

/7o:t-,1bq .70~

.7021 .;DS'2.

.7o-SZ.

~10~'3-,7b'i

lAXlbt(lmst:m (o.NWJoYI vbl~4~l(.s )'\I!4r- Wink.sdJ.tl~t\ "75"-10 '111'7' oL~, ) (r r(. .. LtlV,...dtmi~?) .'70'11- ,1c~7

~i~ -T~r11·-.r1 roJc..!. . 5 "'f.4l) std/~/Il 1..?1IL~<=t .,i~ fl'lLA..

r 5 A.sh. f If) wS

t{;''Y,lsttulrc:tL mt.tft', 1'0 siLit t(, J.ow.~ ~ .;tJS"S - ;713/ Arac.k LIl.4f1uff (20 m.y~ .ioCJl. - .1/03

61 (co Y\'t)

J\o.£krIA1<2.. Wltt\. \)Dl(.~V\\C'.s (~S11 1lAcslItI) b45t\l1'/( QMLs\tt~ h (y~~oe\.'ov·t4t..s

)0-'20 'WI.y. I)l~.

ftll..(.crt6.Ac 8141h .. w.ll.Ltlolt~ t~ff (13 m'1)

~e.SM aV"4l..c:\. voLc.o.V\~'~

l Yh~oltt~~

)0"''2.0 M.'. o.V\4t,,~\t~~ bell $ ~Lt" MlJ.(.$lto R\Jf,tc dNl11l,·\t~ (3~ m.y.)

~(>-z~ ... y.) ''tl<rl',..y tr"'1:. " ... J-tilt. rorrh1i ,U

_f3ctsin tt~ ~eOlj~ h~S4Lt.$_

8rtt..why W"'-,h bet£'ttLtl

~O$kfU1t. YrIf.,s.

5~ fr~"c.ls,-O UOLc.a~·I' f(~L&

62

.112..- .1/)"

. rb ~S"' ..... , 101';­

.;o,~ -. fO~f,

.70& '} - ,70'1, • 7() '8 I.,

.,....7010 .... 7o'S--

I 1,800

7

.. 02

I 1,500

.01

I 1,000

Apparent age

I 500

• -• •

.72

.71 I....-.frlo"'''lrn ~\le.ro.~oIi!.

c:;",,~i

I o

Figure 24. Initial Strontium Isotope Ratios and Ages

of Rocks in Central 1. Redmond formation

2. Ruin Granite

3. Madera Diorite (North si-e of the Pinal Nountains)

4. N~dera Diorite (Nt. Madera and Signal Peak)

5. Mazatzal Mountains (Salt River rpgion)

6. Mazatzal Mountains (Four Peaks ragion)

7. Tortilla Nountains (Netarhyolite)

8. Diabase (Sierra Ancha)

A. Evolution line for mantle-like ~atprial. Rb/Sr = .021

B. Evolution line for average crustal material, Rb/Sr = 0.25

63

Arizona.

from Liv\V\ ~ st 01\ 6~bVJ ,,2.02..

(phCln~r~~\~ toc..k <\~(), .... tJJ.ifi~l· fro"'- S~~fi llALLo.h ,,"t . .J.) l'lli, 6.Y\A. s~u~ro.L l1~fubLi~h~d PkD.1h(s\s.l ill cL,,-f\Y\i Bi(.~(r",o.n)

f~stwoo!) f~r~'ov.~).

,. i D . ~

• ~.

~ : 0 i

• G:l From 5h.fi\"11 ~ 2

~rt~ ot~>/, 7 ~ 0 ~

~ i A i

8 H ~ I R I

• H ~

• o i R I 0 RID ! 0 R o !

2 ! 0 o i A R

! D R R DJ .7000 ,7050 .7200

Figur& 2.5. 87 5r/8 65r initial ratios' for some Oligocene and lower Miocene volcanic rocks (40 to 20 m.y. old) occurring between 37° 30' N to 33° 30' N latitude, and 770° to lTf longitude. Data from Laboratory of Isotope GeochemistlY, University of Arizona. R=rhyolite, A=andesite and D=doreite (i.e., potassic basaltic andesite).

64

a YStJt\ 4-L O)-HI ~ b,(J " 0t\ IWl • ;. ClI,V'Itt4...

Western 1 , I L Eastern

CENOZOIC J

CRETACEOUS /.; Chinle Fm uranium ...... -~

/ E-1 Moenkopi Fm

Kaibab Ls /7 . DeChelly

Ss Coconino Ss

Glorieta Ss

J. < Evaporites ]> halite potash

Z Ft. Apache Ls ----;:5 DEFIANCE

~ Big A Butte p:j S Sandstone & siltstone

Upper POSITIVE r:.q

~ / P; ...... AREA ~

...... "A" ) CiS

b5 §' j -=, lfl

....., ~ \

Amos Wash I Ul (1), Oak \ Middle Q) ~ ~ \ Cibecue

Q) 0 Creek ....., H \ B-1 ~

, -- ...... """

'H " - o Ul

0 "B" Gamma Mb Lower (1)

Q) ~

(1) ? ? B-2 ~1l ~ ~~ 0 ------ ~ N Beta Mb .... f/)-

"""'" ,--- ~

Z Naco Fm -::0"" (1) ~

Z ....., Horquilla Fm "C" e;f/)- '0 r:.q ......

N ",,((; ((;'0 .~ P; ....., ~ .~ ~

~ Ul ~ ~ e;f/)-.'!-.,0 CiS...c1 "00 6Jf/)- (f <\> ... ~ b.O

I-- 0' ......

~ ~ ...;; ",,'"

..... ,..t::1 Mississippian o o>& vf/)-~

CiS -$' ~ C) 0 Devonian

I---- H Cambrian

~ Y. Precambrian t;,". uranIUm

Figure a~. Diagrammatic representation of the regional general geologic setting showing some nomenclatural variations

I.' t'! 1# 30~1tS. en 1·..,1\r~st re.Lo.t\:.. to ur6.v\\IAW\ W\i~Jtr~L..:J;:'t \O'\f\ .

troW\- Pltl'r,-I<.. Q,"~ oth.Q.Y'..s J "77.

65

3 - ........ --_ ...... -

""""' .......... -_.- ........ _ ...... CD •• -. <e.o.Lc.k

So 10 '010 7010

?~ $;02,.

I. f1"c:.~VVlbY'·IO'" Q"1S"I:)-I("()O W\'1') ~toV\"tS QII\A \)OL<.o.Vl·I<.S.

z.. L~~ (to-SO WI.y) f\lA.t~,c:.s of ~c.Q\'Iic.s 3. ~ Lc.tr~;c:k (9. 0 -70 'm.,!) p\I.(S s~ ~~-I.tU\.-' (3)-1~ '(VI'i)

~<:,c':l'\ic.$,

~. JUA~ (Z,2.0-/S'C WI'!'J ~c:.o.n\<.s

~, 1CT1AV\'~ f/l.ll.c.C\~~ (JLf~O - rsS"o 'N\'Y) q~ ~. ~-/.vJiW\.l..i. (Zl.-J3 YI'IY)' o. r

... <1 l 'I' \)"O"\c.~YI(c.s..

1. B~ ~fZ~ ~(JS"'-om.y) <b. Yl-l,a T~r\ \tHy h'1h-PtJi4Sk \JOLc..o.Vl\<'S (2.."2. - I~ YI\.,/,}

fl"t4r~ 27. Po1Dt.sl -- s',L,'l..D... ,l\~,rA~S for rll-\1'oVl'I<.. ~~~ VoLc.c..Y"" ro& bf so .... fhCl.r~ Ar~~4\,. po:tt\ UM\fil".i,~ AM! fYOfo..s4.!' roc.k.. d4)\ V'I~mU rroW\ tA~p",bLI.~ktl wort 0 t S1'A~I,<y g. Ki,t~) 117i"'11.

66

NW (oRNf( OF STATE.

'" s: 1/ V o

~ to ~ V 0 "....

:..J 0

L.l, mt.~

10

noTe.

SE COIINf.R Of STATE.

S\).;~,,,t. fi Ll,'", -tho. iI."·,,,, ,,, .. hoi, by "t ho. Sq.;" .. .,A, R •• ,~ .I.;.r".b""" ....

. "~"'rl<x .,,,,,,blo, ... of l'''' ..... bnt, r7r.c.\.~s.Tic.J., tL.;c.k. "1,, of ....... " <.L".T,<'. l.'r.",t.~ i .. 1,,,;.,,;, 'P ... ;n ... riH-n.Li<\'\4 ~ •• ~Lts .lJ.p .;rtol ;" """t..9. p.:.r ~ sio.tt.

,,,I..l .. <!,,o,.., - ,.L,,1',~ .... L .. -doLle .• Li", ... of "i,.\m"rrt~ • uoLc.o. .. ;u wi1~ ,';;1" ..... t .. 't .. c\. r ... d.b.A,. \f.k."·Ic.~ I(o .. ,· ... -t .. f ... ,ul.'$·it~ r),y.l.·iTt ;, .. ',",I:. ,i1\., h,l.-X 1"~<~1'tu l .. tit... '

~ frt-( .... ~ ",".0 uol, .... ·,. f,;. ... ,,6.

Co .. r'~ ' ..... ·'n .. ", Tllt.cl J thi.k <1 .. ,1" S',\I.'''C-'-S.I c."t ... · ... i""~ r __ l~'ds , .. r1-.e",s. V.lc,Q"ic.s .. ,.." s" •• 1_r1 \l'Io ·'-f-rT.,,<,~ j", 1~,~,

.,\ M.""C.". ~o -------

L;"t.

rYO~ SCArb oro v-,k 4.H~' W',Lt ('",).

CAr~n;lAm.. Oc.c.urrttl(.ts (*;)

67

REFERENCES

General References

Anderson, CA and Silver, LT (1976) - Yavapai Series - A Greenstone Belt Arizona Geology '£ociety Digest, 10, p. 13-26.

Bailey, EH (1969)-Mercury. In Mineral and Water Resources of Arizona. Arizona Bureau of Mines Bulletin, 180, p. 226-230.

Banks, NG and Krieger, MH (1977) - Geologic Map of the Hayden Quad, Pinal and Gila Counties, Arizona. USGS Map GQ-1391.

Bromfield, CS and Shride, AF (1954) - Mineral Resources of the San Carlos Indian Reservation. USGS Bulletin 1027-N.

Cornwall, HR; Banks, NG and Phillips, CH (1971) Geologic Map of the Sonora Quadrangle, Pinal and Gila Counties, Arizona. USGS Map GQ-1021.

Cornwall, HR and Krieger, MH (1975) - Geologic Map of the Grayback Quadrangle, Pinal County, Arizona. USGS Map GQ-1206.

Cornwall, HR and Krieger, MH (1975) - Geologic Map of the Kearny Quadrangle, Pinal County, Arizona. USGS Map GQ-1188.

Cornwall, HR and Krieger, MH (1978) - Geologic Map of the E1 Capitan Mountain Quadrangle, Gila and Pinal Counties, Arizona. USGS Map GQ-1442.

Cummings, RR (1978) (ASARCO). The Sacaton Porphyry Copper Deposit. Arizona Bureau Geologic and Mineral Technology Special Paper 2, p. 83-84.

Damon, PE (1969), Correlation and Chronology of are Deposits and Volcanic Rocks; U.S. Atomic Energy Comm. Ann. Prog. Rept. No. COO-689-120, 90 p.

Darton, NH (1925) Resume of Arizona Geology: Arizona Bureau Mines Bulletin 119.

Davis, GH and Coney, PJ (1979). Geologic Development of the Cor­dilleran Metamorphic Core Complexes. Geology 7, p. 120-124.

Gasti1, RG (1958), Older Precambrian Rocks of the Diamond Butte Quadrangle, Gila County, Arizona. GSA Bull 69 p. 1495-1514.

Granger, HC and Raup, RB(1964) Stratigraphy of the Dripping Spring Quartzite, Southeastern Arizona. USGS Bulletin 1168. 119 p. Plate 1 is detailed outcrop map of DS, Apache Gp in Mesa Quad.

68

General References (Cont.)

Hammer, DF; Webster, RN and Lamb, DC (1962) Geologic Features of the Superior Area, Pinal County, Arizona. New Mexico Geo1. Soc. Guidebook #13 (Mogollon Rim), p. 148-152.

Holloway, JR and Cross C. (1978) The San Carlos Alkaline Rock Association. Arizona Bureau Geo1. and Min. Tech. Special Paper 2, p. 171-173.

Huddle, JW and Dobrovo1ny, Ernest (1952), Devonian and Missis­sippian Rocks of Central Arizona: U.S. Geo1. Survey Prof. Paper 233-D, p. 67-112.

(2)

Jahns, RH (1952) Pegmatite Deposits of the White Picacho District, Maricopa and Yavapai Counties, Arizona. Arizona Bureau of Mines Bull. 162. 105 p., pegmatite study in Wickenburg area. See road log by London and Burt, Arizona, Bureau of Geology and Mineral Technology Special Paper 2, p. 61-66.

Jenny, JP and Hauck, HR (editors) (1978). Proceedings of the Por­phyry Copper Symposium. Arizona Geo1. Soc. Digest, Vol. 11 178 p.

Keith, SB (1979) The Great Southwestern Arizona Oil and Gas Play. Arizona Bureau of Geology Fie1dnotes ~(1) p. 10-14.

Keith, WJ and Theodore, TG (1979) Tertiary Volcanic Rocks of the Mineral Mountain and Teapot Mountain Quadrangles, Pinal County, Arizona. USGS Open File Report 79-716. 19 p.

Knechtel, MM (1938) Geology and Ground-Water Resources of the Valley of Gila River and San Simon Creek, Graham County: USGS Water­Supply Paper 796-F. Pl. 46, 1:96,000.

Krieger, MH (1961) Troy Quartzite (younger Precambrian) and Bo1sa and Abrigo formations (Cambrian), northern Ga1iuro Mountains, southeastern Arizona, ;lI\ Short papers in the geologic and hy­drologic sciences: US Geol. Survey Prof. Paper 424-C, p. C160-C164.

Krieger, MH (1977) Large Landslides, composed of megabreccia, inter­bedded into Miocene Basin deposits, Southeastern Arizona. USGS Prof. Paper 1008.

Krieger, MH; Cornwall, HR and Banks, NG (1972) Big Dome Formation and revised Tertiary stratigraphy in the Ray-San Manuel area, Arizona. In USGS Bulletin 1394-A (Changes in Stratigraphic nomenclature by the USGS, 1972). p. 54-63.

69

(3)

General References (Cont.)

Lausen, Carl and Gardner, ED (1927) Quicksilver resources of Arizona: Arizona Bur. Mines Bull. 122.

Livingston, DE and Damon, PE (1968) The ages of stratified Precambrian rock sequences in central Arizona and northern Sonora. Canad. J. Earth Sci ~, p. 763-772.

Livingston, DE; Mauger, RL, and Damon, PE (1968) Geochronology of the emplacement, enrichment and preservation of Arizona porphyry copper deposits. Economic Geology ~, p. 30-36.

Metz, RA and Rose, AW (1966) Geology of the Ray Copper deposit. In Geology of the Porphyry Copper deposits, Southwest North America Ed. by Titley and Hicks. p. 176-188.

Miller, HW (1962) Cretaceous rocks of the Mogollon Rim area in Arizona. New Mexico Geol. Soc. Guidebook #13 (Mogollon Rim) p. 93.

Moorbath, S.; Hurley, PM and Fairbairn, HW (1967) Evidence for orlgln and age of mineralized Laramide intrusives in SW United States from Sr isotope and Rb/Sr measurements. Economic Geology ~ p. 228-236.

Moore, RT (1968) Mineral deposits of the Fort Apache Indian Reserva­tion, Arizona. Arizona Bureau of Mines Bull. 177. 84 p.

Olmstead, HW and Johnson, DW (1966) Inspiration Geology. In Geology of the Porphyry Copper Deposits, Southwest North America. ed. by Titley and Hicks. p. 143-150.

Peirce, HW (1976a) Elements of Paleozoic tectonics in Arizona. Ariz. Geol. Soc. Digest 10, p. 37-58.

Peirce, HW (1976b) Tectonic significance of Basin and Range thick evaporite deposits. Arizona Geol. Soc. Digest 10, p. 325-340.

Peirce, HW; Damon, PE and Shafiqullah, M. (in press). An Oligocene(?) Colorado Plateau edge in Arizona. Tectonophysics (in press, V.6l).

Peirce, HW and Scurlock, JR (1972) Arizona Well Information, Arizona Bureau of Mines Bulletin 185, 195 p.

Peterson, DW (1960) Geology of the Haunted Canyon Quadrangle, Arizona. USGS Map GQ-128.

Peterson, DW (1966) Geology of Picketpost Mountain, northeast Pinal County, Arizona: Ariz. Geol. Soc. Dig. v. 8, p. 158-176. (See also Nelson E (1966).

Peterson, DW,(1968) Zoned ash-flow sheet in the region around Superior, Arizona: Ariz. Geol. Soc. Southern Arizona Guidebook III, p. 215-222.

70

(4)

General References (Cont.)

Peterson, DW (1969) Geologic Map of the Superior Quadrangle, Pinal County, Arizona. USGS Map GQ-8l8.

Peterson, NP (1961) Preliminary Geologic Map of the Pinal Ranch Quadrangle, Arizona. USGS Map MF-8l.

Peterson, NP (1962) Geology and Ore Deposits of the Globe-Miami District, Arizona. USGS Prof. Paper 342. 151 p.

Peterson, NP (1963) Geology of the Pinal Ranch Quadrangle, Arizona. USGS Bulletin l14l-H. 18 p.

Peterson, NP and Swanson, RW (1956) Christmas copper mine, Gila County: USGS Bull. 1027-H.

Pewe, TL (1978) Terraces of the Lower Salt River Valley in Relation to the Late Cenozoic History of the Phoenix Basin, Arizona. Arizona Bureau of Geol. and Min. Tech. Special Paper #2, p. 1-13.

Ransome, FL (1903) Geology of the Globe copper dist.: USGS Prof. Paper 12. (a) Pl. 1, 1:62,500 (same area as No. 173, fig. 2); (b) pl. 15, 1:12,000. Also mine map.

Ransome, FL (1905) Globe Quadrangle: USGS Geol. Folio 111 (a) Map, 1: 62,500; (b) Map, 1: 12 ,000.

Ransome, RL (1923), Ray Quadrangle: USGS Geo1. Folio 217. Map, 1:62,500 (Map, 1:12,000, same area as No. 43c).

Ransome, RL (1914), Copper deposits near Superior: USGS Bull. 540-D. Fig. 13, 1:13,500.

Rehrig, WA and Heidrick, TL (1976) Regional tectonic stress during the Laramide and late Tertiary intrusive periods, Basin and Range Province, Arizona. Arizona Geo1. Soc. Digest 10, p. 205-228.

Ross, CP (1925) Ore deposits of the Saddle Mountain and Banner mining dists.: USGS Bull. 771. (a) Pl. 1, and pl. 17, both 1:62,500; (b) pl. 13,1:3,600.

Ross, C.P., Geology and ore deposits of the Aravaipa and Stanley mining dists.: USGS Bull. 763. (a) Pl. 1, 1:125,000; (b) Fig. 7, 1:1,600; (c) Fig. 8, 1:2,400.

Scarborough, RB and Wilt, JC (1979) A study of uranium favorabi1ity of Cenozoic sedimentary rocks, Basin and Range Province, Arizona. USGS open file report 79-1429 106 p.

Schmidt, EA (1971) Belts of Laramide-age intrusive rocks and fissure veins in south-central Arizona. Ariz. Geo1. Soc. Digest 1 p. 61-69.

71

(5 )

General References (Cont.)

Schumacher; DP; Witter, DP; Meader, SJ and Keith, SB (1976) Late Devonian Tectonism in southeastern Arizona. Ariz. Geol. Soc. Digest 10 p. 59-70.

Shafiqullah, M.; Lynch, DJ and Damon, PE (1976) Geology, Geo­chronology and geochemistry of the Picacho Peak area, Arizona. Ariz. Geol. Soc. Digest 10 p. 305-324.

Shafiqullah, M. and others (1978) Mid-Tertiary magmatism in southern Arizona. New Mexico Geol. Society Guidebook 29 (Land of Cochise), p. 231-241.

Sheridan, MF (1978) The Superstition cauldron complex. Ariz. Bureau Geol. and Min. Tech. Special Paper 2, p. 85-96.

Sheridan, MF; Stuckless, JS and Fodor, RV (1970), A Tertiary silicic cauldron complex at the northern margin of the Basin and Range province, central Arizona, USA: Bull, Volcanol, v. 34, p. 649-662.

Short, MN; Galbraith, FW; Harshman, EN: Kuhn, TH and Wilson, ED (1943)Geology and ore deposits of the Superior m~n~ng area, Arizona: Arizona Bur. Mines Bull. 151, Geol. ser. 16, 159 p.

Shride, AF 1952, Localization of Arizona chrysotile asbestos deposits (abs.): Geol. Soc. American Bull., v. 63, no. 12, pt. 2, p. 1344.

Shride, AF (1967) Younger Precambrian Geology in Southern Arizona. USGS Prof. Paper 566, 89 p.

Silver, LT (1960), Age determinations on Precambrian diabase differentiates in the Sierra Ancha, Gila County, Arizona (abs): Geol. Soc. American Bull., v. 71, no. 12, pt. 2, p. 1973-1974.

Simmons, WW and Fowells, JE, (1966) Geology of the Copper Cities Mine. In Geology of the Porphyry Copper Deposits, Southwest North American. ed. by Titley and Hicks, p. 151-156.

Slatt, RM and others (1978) Precambrian Pikes Peak Iron-Formation, Central Arizona. Ariz. Bureau of Geol. and Min. Tech. Special Paper 2, p. 73-82.

Stuckless, JS 1971, The petrology and petrography of the volcanic sequence associated with the Superstition caldera. Supersti­tion Mountains, Arizona (Ph.D. thesis): Stanford, California, Stanford University, 112 p.

72

(Addition)

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General References (Cont.)

Stuckless, JS and O'Neil, JR (1973), Petrogenesis of the Superstition­Superior volcanic area as inferred from strontium-and oxygen-isotope studies: Geol. Soc. American Bull. v. 84, p. 1987-1998.

Stuckless, JS and Naesar, CW (1972) Rb-Sr and fission track age deter­minations in the Precambrian plutonic basement around the Super­stition volcanic field, Arizona. USGS Prof. Paper 800-B. p. 191-194.

Summer, JS; Schmidt, JS and Aiken, CLV (1976) Free-air gravity anomoly map of Arizona. Ariz. Geol. Soc. Digest 10 p. 7-12.

Suneson, NH and Sheridan, MF (1975)., Geology of the northern portion of the Superstition-Superior volcanic field. Maricopa and Pinal Oounties, Arizona (abs): Geol. Soc. America, abs. with prog., v. 7, no. 7, pI 1287-1288.

Theodore, TG; Keith, WJ; Till, AB.;, and Peterson, J. (1978) Pre­liminary Geologic map of the Mineral Mountain 7~ minute quadrangle, Arizona. USGS Open file report 78-468. Includes KIAr analytical data by S. Creasey.

Thorpe, DG and Burt, DM (1978) Precambrian metavolcanic rocks of the Squaw Peak area, Maricopa County, Arizona. Ariz. Bur. Geol. and Min. Tech. Special Paper 2, p. 101-106.

Titley, SR and Hicks, CL (1966) Geology of the porphyry copper deposits, southwestern North America. The University of Arizona Press, Tucson. 287 p.

Willden, R. (1964) Geology of the Christmas Quadrangle, Gila and Pinal Counties, Arizona. USGS Bulletin l16l-E. 64 p.

Wilson, ED (1939) Pre-Cambrian Mazatzal revolution in central Arizona: GeoL Soc. American Bull., v. 50, no. 7. (a) PI. 10, 1:80,000; (b) pl. 11, 1:62,500 (c) pl. 12, 1:125,000; (d) Fig. 4, 1:174,240; (e)Fig. 6, 1:187,500; (f) Fig. 9, 1:125,000 (same area as No. 47, pI. 30); (g) Fig. 10, 1:160,000.

Wohletz, KH (1978) The eruptive mechanism of the Peridot Mesa vent, San Carlos, Arizona. Ariz. Bur. Geol. and Min. Tech. Special Paper 2, p. 167-171.

Moore, RT (1972) Geology of the Virgin and Beaverdam Mountains, Arizona. Arizona Bureau of Mines Bulletin 186. p. 65.

Keith, SB (1978) The Origin of Southern Arizona Porphyry copper deposits Hypothesis. Arizona Bureau of Geology Fieldnotes ~ (1-2), p. 8-13.

Keith~ SB (1975)_ 100,,50 m~y. tectonic patterns in central Arizona and their intplications ;for Co;rdtlle;t'an Orogenesis., GSA abstracts 2,C7}, p. 1140.

Koski, RA (19791 Geology !:lnd porphyry copper'"""type alte'ration,.-mineralization of igneous rocks, Christmas Mine, Gila Co., Arizona. TISGS open file report 7~h-844.

Banks NG, and others (1972) Chronology of intrusion and ore deposition at Ray? Arizona: Part 1, K,Ar ages. Economic Geology, Q, p. 864-878.

73

RELEVANT MS AND PH.D. THESES

Bejnar, Wa1domere (1952) Geology of theRuin'B~sinarea, Gila County Arizona. Univ. of Arizona, Ph.D. Thesis, 103 p.

Clary, TA (1970) Geology of the Schultz Granite and related copper mineralization. ASU (Tempe) MS Thesis. 37 p. Superior-Globe area.

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Conway, CM (1976) Petrology, structure, and evolution of a Precambrian volcanic and plutonic complex, Tonto Basin, Gila County, Arizona. Cal. lnst. Tech. Ph.D. Thesis, 523 p. abst: Distr. Abstr. Int. vol. 37 no. 7, p. 3309B-3310B.

Fouts, JA (1974) Petrology and chemistry of some diabase sills in central Arizona. University of Arizona, Ph.D. Thesis, 172 p. Abstr: Diss'n abstr. 1l (8) p. 3985B - 3986B.

Galbraith, FW (1935) Geology of the Silver King area, Superior, Arizona. Univ. of Arizona unpub. Ph.D. thesis. 154 p.

Gasti1, G (1953) Geology of the eastern half of the Diamond Butte quadrangle, Gila County, Arizona. Univ. of Calif. at Berkeley, Ph.D.

Gerrard, TA (1964) Environment studies of the Ft. Apache member, Supai Formation (Permian), East-Central Arizona. Univ. of Arizona, Ph.D. Thesis. 187 p.

Gustafson, LB (1962) Paragenesis and hypogene zoning at the Magma Mine, Superior, Arizona. Harvard U. Ph.D. Thesis.

Harshman, EN (1939) Geology of the Belmont-Queen Creek area, Superior, Arizona. Univ. of Arizona, unpub. Ph.D. Thesis. 167 p.

Kay1er, KL (1978) Geology of the Humbo1t Mountain area, Arizona. ASU (Tempe) MS Thesis. 101 p.

Kiersch, GA (1947) Geology and Ore deposits of the Seventy Nine mine area, Gila County, Arizona. Univ. of Arizona Ph.D. Thesis. 124 p.

Koski, RA (1978) Geology and porphyry copper-type alteration - mineraliza­tion of igneous rocks at the Christmas Mine, Gila County, Arizona. Stanford U. Ph.D. Thesis. 268 p. (See also USGS OFR 79-844).

Lausen, C (1923) Geology of the Old Dominion Mine, Globe, Arizona. Univ. of Ariz. unpub. MS Thesis. 155 p.

Livingston, DE (1969) Geochronology of older Precambrian rocks in Gila County, Arizona. Univ. of Arizona unpub. Ph.D. thesis. 216 p.

74

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Ludwig, KR (1974) Precambrian geology of the central Mazatzal Mountains, Arizona (Part I) and lead isotope heterogeneity in Precambrian igneous feldspars (Part II). Cal. Inst. Tech. Ph.D. Thesis.

Marlowe, JI (1961) Late Cenozoic geology of the lower Safford Basin on the San Carlos Indian Reservation, Arizona. Univ. of Arizona Ph.D. Thesis, 184 p.

McConnell, R (1972) The Apache Group (Proterozoic) of Central Arizona. UC at Santa Barbara Ph.D. Thesis.

McCurry, WG (1971) Mineralization and paragenesis of the ores, Christmas Mine, Gila County, Arizona. ASU (Tempe) MS Thesis.

Peterson, DW (1961) Dacite ash flow sheet near Superior and Globe, Arizona. Stanford U. Ph.D. Thesis. 130 p.

Pine, GL (1968) Devonian stratigraphy and paleogeography in Gila, Graham, Greenlee and Pinal Counties, Arizona. Univ. of Arizona Ph.D. The­sis, 160 p.

Reynolds, SJ (in progress) (Metamorphic Core complexes at South Mountain and White Tank Mountains) Univ. of Arizona Ph.D. Thesis in progress.

Schmidt, EA (1971) A Structural Investigation of the northern Tortilla Mountains, Pinal County, Arizona. Univ. of Arizona unpub. Ph.D. Thesis.

Short, MN (1923) Deep-level Chalcocite at Superior, Arizona and Butte, Montana. Harvard U. Ph.D. Thesis.

Shride, AF (1961) Some aspects of Younger Precambrian geology in southern Arizona. Univ. of Arizona Ph.D. Thesis.

Smith, D (1969) Mineralogy and petrology of an olivine diabase sill complex and associated unusually potassic granophyres, Sierra Ancha, central Arizona. Cal. Inst. of Tech. Ph.D. Thesis.

Suneson, NH (1976) The geology of the northern portion of the Super­stition-Superior volcanic field, Arizona: Tempe, Arizona, Arizona State University, M.S. thesis, 114 p.

(addn'l) Laine, RP (1974) Geological-geochemical relationships between porphyry copper and porphyry molybdenum deposits. Univ. of Arizona PhD thesis, 326 p.

75

URANIUM RELATED REFERENCES

Granger, HC and Raup, RB (1969) Geology and uranium deposits in the Dripping Spring Quartzite, Gila County, Arizona. USGS Prof. Paper 595. 108 p.

Kaiser, EP (1951) Uraniferous quartzite, Red Bluff prospect, Gila County, Arizona. USGS Circular 137. 10 p.

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Peirce, HW; Jones, N and Rogers R. (1977) A survey of uranium favorability of Paleozoic rocks in the Mogollon Rim and slope region-east central Arizona. Ariz. Bureau of Geol and Min. Tech. Circular 19. 60 p.

Schwartz, RJ (1978) Uranium occurrences of Gila County, Arizona. Dept. of Energy report RME-207l, 60 p.

Still, AR (1962) Uranium at Copper Cities and other porphyry copper deposits, Miami district, Arizona. Harvard U. Ph.D. Thesis.

Texas Instruments, Inc. (1979) Aerial radiometric and magnetic re­connaisance survey of portions of Arizona-New Mexico. DOE open file report GJBX-23(79). (general geology and airborne radiometries covers SE 1/3 of Mesa quad) p. 5-10 report 110

"possible uranium prospects" in Mesa quad.

Williams, FJ (1957) Structural control of uranium deposits, Sierra Ancha region, Gila County, Arizona: U.S. Atomic Energy Comm. RME-3l52, 121 p., prepared by Columbia University for and is­sued by U.S. Atomic Energy Comm. Tech. Inf. Service, Oak Ridge, Tenn.

Wright, RJ (1950) Reconnaisance of certain uranium deposits in Arizona: U.S. Atomic Energy Comm. RMO-679, 21 p., issued by U.S. Atomic Energy Comm. Tech. Inf. Service, Oak Ridge, Tenn.

76

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2 - 0 m.y. 10 - 2 m.y. 15 -10m.y.

30 -15 m.y.

50 YI1.y •

80 m.y.

2.a4 m.y.

570 WI.y.

Qb - quarternary basalts Tb - basalts Tbo-"Hickey" basalts Tvs- silicic volcanics Tvi- intermediate volcanics Tv - volcanics Ta - andesites Ti - plugs, intrusive masses Tm - recrystallized rocks of

metamorphic core complexes

La - andesite Lv - volcanics Ldi- diorite Lg - granite

Ks Cretaceous clastic sediments

PP - Pennsylvanian - Permian sediments.

DM - Devonian - Mississippian sediments.

Q - valley fill material capped by Pleistocene sediments.

Ms- Miocene sediments Ts- Tertiary seds. - unk age OM- Oligocene - Miocene clastic

sediments, including Eocene(?) Oligocene rim gravels

Dikes, Laramide and Te rtiary Age.

{PPs - Supai Formation PPn - Naco Formation

COS- Cambrian - Ordovician Silurian sediments.

T - Troy Quartzite d - 1100 m.y. old diabase sills-gabbro complex A - Apache Group sediments (Pioneer Shale, Dripping Spring Quartzite,

Hesca1 Limestone) pdi- diorite and related intrusives pg- granite

pmp- metamorphosed sediments, volcanics pry- rhyolite flows, pyroclastics

pm- Hazatza1 Quartzite and related sediments ps- schist and other metamorphics

high angle faults, dot on downthrown side

thrust faults, pattern on upper plate

same geologic unit

, " .... ,~

Laramide and Tertiary dikes

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50 WI.y.

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Qb - quarternary basalts Tb - basalts Tbo-"Hickey" basalts Tvs- silicic volcanics Tvi- intermediate volcanics Tv - volcanics Ta - andesites Ti - plugs, intrusive masses Tm - recrystallized rocks of

metamorphic core complexes

La - andesite Lv - volcanics Ldi- diorite Lg - granite

Ks Cretaceous clastic sediments

PP - Pennsylvanian - Permian sediments.

DM - Devonian - Mississippian sediments.

Q - valley fill material capped by Pleistocene sediments.

Ms- Miocene sediments Ts- Tertiary seds. - unk age OM- Oligocene - Miocene clastic

sediments, including Eocene(?) Oligocene rim gravels

Dikes, Laramide and Te rtiary Age.

{PPs - Supai Formation PPn - Naco Formation

COS- Cambrian - Ordovician Silurian sediments.

T - Troy Quartzite d - 1100 m.y. old diabase sills-gabbro complex A - Apache Group sediments (Pioneer Shale, Dripping Spring Quartzite,

Mescal Limestone) pdi- diorite and related intrusives pg- granite

pmp- metamorphosed sediments, volcanics pry- rhyolite flows, pyroclastics

pm- Mazatzal Quartzite and related sediments ps- schist and other metamorphics

high angle faults, dot on downthrown side

,-,J', . t 'V" maJor s reams

~ thrust faults, pattern on upper plate

same geologic unit

t " "". ',.

Laramide and Tertiary dikes