Black Rock Desert Impact Theory

Black Rock Desert Impact TheoryBlack Rock Desert Impact Theory

Presented by Ian KluftCalifornia Meteorite Club

Escondido, CaliforniaSeptember 14, 2014

Black Rock Desert Impact Theory

● Black Rock Desert is in northwest Nevada– 2 hour drive north of Reno

● This theory proposes an impact structure (eroded crater)● Presentation order

– How the theory started

– Science of impact craters on Earth

– Current observations at Black Rock

– Upcoming research plans

Current research status

● Scientific method usually goes in this order– Propose and test hypotheses

– Investigate theories

– Publish peer-reviewed papers

● This is currently a theory● There isn't a peer reviewed paper... yet

– But that's the goal

● The evidence one way or the other exists in the rocks– The data will tell the story

How the Black Rock Crater Theory started

● attempts at 1st amateur rocket to space 1998-2004● exploring Black Rock Range in rocket search area 2002-2005● bizarre rocks, "strangest volcano I've ever seen" 2002-2006

– I've seen large & small, old and young volcanoes at Mt Shasta area

– At Black Rock I didn't see volcanic structures: lava flows, cinder cones, etc

– Some rocks are the right color to look like lava

● impact crater theory 2007-present● outline found in mountains 2009● I had to learn about the science of impact crater recognition...

Science of Impact Craters

“Traces of Catastrophe” by Bevan M French

This book by a Smithsonian Institution geologist has become the definitive resource on the science of impact craters.

You can download the PDF e-book athttp://www.lpi.usra.edu/publications/books/CB-954/CB-954.intro.html

Image: Lunar & Planetary Institute

Science of Impact CratersDifferences from traditional Geology

● "Cryptoexplosion structures"– Until the 1960's, geologists didn't believe there were any impact craters on Earth

– “cryptoexplosion” was used for unexplained explosion structures

● Slow processes vs instantaneous– Traditional geology wants all processes to be over millions of years

● Impacts are rare on Earth– Unlike other rocky bodies in the solar system, Earth slowly erases its craters

● Enormously energetic– Asteroids never make soft landings

– These are violent explosions that entirely destroy the impactor

Science of Impact CratersEugene Shoemaker (1928-1997)

● founder of impact geology● studied structure of NV nuke test craters● discovered Barringer Crater has same structure● theorized Earth is covered in craters

– like the Moon

● studied/proved many impact craters● co-discoverer of SL9 comet that impacted Jupiter in

1994– made Earth aware of impact threat

Image: USGS via Wikipedia

Science of Impact CratersFormation of impacts

● Crater about 10-20 times diameter of impactor– Depends mostly on speed - minimum 25,000 mph

● hypervelocity impact destroys impactor– mostly melted

● contact/compression stage– extreme shock on rocks

● excavation stage– explosion blows out crater

Science of Impact CratersFormation of impacts (cont'd)

● modification stage– debris falls down

– hot rocks cool down

● larger impacts, complex craters– over 10km diameter on Earth

– terrace collapses on rim

– central uplift pushed up from sides

– uplift ring in largest craters

Image: NASA via Wikipedia

Science of Impact CratersDecay Processes

● Earth slowly destroys its craters● Erosion wears them away● Faulting distorts them● New layers bury them● Plate tectonics slowly erases and renews the crust● But the Moon still shows what firing line the Earth is in

Science of Impact CratersHow to Recognize Them

● from Traces of Catastrophe, Appendix 1● occurs in any kind of bedrock● generally single structures● generally circular● nearly any size: <1km to >100km● relatively shallow, not a deep structure

Science of Impact CratersHow to Recognize Them (cont'd)

● anomalous feature within region– unusual geology in circular area

– local deformation, faulting, breccias

– unusual breccias within structure

– possible central uplift peak or ring

– shatter cones● one form of proof of impact● conical shock fractures – even volcanoes can't make them

Science of Impact CratersHow to Recognize Them (cont'd)

● Look for geologic mysteries in literature– intense, sudden, localized

– conventional explanations fail

– unusual “volcanic” explosions

● Measure geophysical attributes– gravity

– magnetic

– seismic

Science of Impact CratersHow to Recognize Them (cont'd)

● rock types– breccias

● Broken up and re-cemented rocks● Always present in impacts, can be formed other ways too

– melt rocks● Igneous rocks, but contents come from melting local target rocks

● microscopic shock effects– Deformation, fracturing, melting– Most proof of impact requires an electron microscope

Science of Impact CratersHow to Recognize Them (cont'd)

● Go explore confirmed impact sites● I've visited...

– Barringer Crater (Meteor Crater) AZ

– Upheaval Dome, UT

– Sierra Madera Crater, TX

– Santa Fe Impact Structure, NM

– Middlesboro, KY

– Wells Creek & Flynn Creek, TN

– Odessa Crater, TX

● Share your pictures– I've posted many on Wikipedia over the years

Current observations

● Observations started with rocks in 2007– Trips to explore and observe at Black

Rock– Online study: Nevada Bureau of Mines

and Geology● Located at University of Nevada, Reno● Scanned geological filings back to late

1800's

● Outline found in 2009– Yes, it took 2 years!– It's heavily eroded

Photo by Ian Kluft

Current observations(cont'd)

● Breccia (broken/re-cemented rocks) above fractured basement rocks– We find this many places at Black

Rock Desert, miles and miles apart

– Impact theory suggests these are rocks that got smashed, and rocks that landed on them

– Best examples so far in Black Rock Range

Photo by Ian Kluft

Current observations(cont'd)

● Close spacing between joints in basement rocks show intense stress– Credit to Bob Verish for making this

important observation

– Joints are larger cracks, like mini-faultlines

– After he pointed this out, we've found basement rocks across miles with narrow criss-crossing jointing Photo by Ian Kluft

Current observations(cont'd)

● Testing the hypothesis:These structures in the Black Rock Range (and elsewhere in the region) look like volcanic necks.

● If they are, it would point toward volcanic origin and away from the impact theory.

Photo by Ian Kluft

Current observations(cont'd)

● The supposed “volcanic necks” are actually made of breccia! They are gigantic breccia dikes.

● This points toward an impact origin and away from volcanic.

● It suggests impact debris that filled giant cracks.

Photo by Ian Kluft

Current observations87km / 54 mile Ring in the Mountains

● 9 mountain ranges are either arc-shaped or change elevation significantly on the circle.

● Crutcher Canyon is concentric outside the circle, apparent rim terrace collapse

● Kamma Mountains are concentric inside the circle, apparent uplift ring

Terrain map by Google Maps, annotations by Ian Kluft

Current observations87km / 54 mile Ring in the Mountains (cont'd)

● All the highest peaks of the Black Rock region are on the circle.● All streams in the Black Rock watershed flow into the circle and

sink into the playa.– The Quinn River Sink (lowest point) is at the center of the circle.

● Volcanoes do not make nice circles on this scale!– Compare to Yellowstone Caldera: 55x72km / 34x45 miles

– The scale and quality of the circle point to an impact, not a volcano

Current observationsWhy no shatter cones?

● Shatter cones are only proof of impact that don't require an electron microscope

● At first I wanted to focus on looking for them– It seemed easier

● Shatter cones occur in a very small percentage of the radius– At Black Rock, there is apparently an uplift ring

– So the bedrock at the center is buried under the lakebed

● I realized this while visiting Middlesboro Crater in Kentucky

Geologic mysteries at Black RockSoldier Meadows Tuff

● A “tuff” is a volcanic ashfall deposit

● 1980 MS thesis by Edmund Stuart describes a mystery

● Soldier Meadows Tuff is a single “cooling unit” - it all came down in one sudden event, over 200m thick.

● Where's such an enormous volcano nearby?

Photo by Ian Kluft

Geologic mysteries at Black RockSoldier Meadows Tuff (cont'd)

● Impact theory suggestions about Soldier Meadows Tuff– It is located just outside the 87km ring where ejecta is expected

– It would have landed in one sudden event, as observed

– It would be very thick just outside the rim, as observed

– Under the impact theory, it should be an impact ejecta layer

– For an impact this size, the ejecta layer should be very thick

Geologic mysteries at Black RockSulphur Mining District

● 1980 geological summary by geologist Andy Wallace

● Mystery of altered rocks– And odd breccia dikes

Photo by Ian Kluft

Geologic mysteries at Black RockSulphur Mining District (cont'd)

● “White breccia” rock layer feeds down into cracks– Mystery how those were altered but not the rocks below

– Also increasing “volcanic” rocks as layers go up● still old rocks from below too● impacts do that – volcanoes don't

– Doesn't fit well with presumed hydrothermal alteration

– Fits well with alteration and melting from an impact● Big fragments land first, followed by smaller rocks, increasing melt● Suggests the “volcanic” rocks are actually impact melt

Upcoming research plans

● Find an electron microscope– Not just any scope

– We need a lab with experience recognizing impact shock effects● For example, shocked quartz

● Aerial video of mountains around rim– Not proof itself, potential for interesting data collection

● Write a paper– Co-authored with Bob Verish and others who contribute to the effort

Conclusions

● An 87km / 54mile impact structure at Black Rock, if confirmed, would be the second largest in America.– The largest is the 90km Chesapeake Bay Crater.

– You can't visit Chesapeake Bay crater because it's all buried.

● Most of Black Rock region is federal lands– Anyone can go there.

– It's a tremendous opportunity for any researchers to study it.

– It could be a big resource for education about impacts.

Questions?

Thank you!