State of the Research - January 2009

[Back up to Black Rock Desert suspected impact crater page]

by Ian Kluft
e-mail: i k (dash) b r c r a t e r -at- t h u n d e r [dot] s b a y {dot} o r g
January 3, 2009

On this page...

Last year after the Winter when the weather made Black Rock inaccessible, I posted a summary of what progress we had made and what we had learned. With 2008 now behind us, it's time to summarize another year. I'll also add a Q&A section to address some recurring questions.

In 2008 we faced the challenge of high fuel prices which made it more difficult to organize enough volunteers for a trip. One doesn't just go to the Black Rock Desert alone, at least not if there's any concern for safety. We watch out for each other and we bring multiple vehicles for self-rescue capability. So we only got two trips there for the crater research, both in September. Both those trips were very much worth the effort.

A geologist looks at the site

On the September 5-7 trip, which we named "Crater Assault 3", we had the privilege of having a geologist with impact crater experience visit the site for the first time since the crater theory was proposed. I want to thank Bob Verish for making the long trip there. I also want to be careful not to say or imply anything for him - like any good scientist, we know there isn't enough evidence yet for him to make any kind of endorsement. Yet I can say that Bob has been encouraging like a mentor, gently challenging me with things to look for that he would want to see in order to take an impact theory seriously. So after many times talking and e-mailing about it, now he had a chance to see it first hand.

That said, Bob is a tough audience as well. He co-authored the paper which disproved any impact origin for the so-called "Elko Crater Field" in another part of Northern Nevada. They turned out to be all sinkholes.

There was only enough time in the schedule for about a day and a half camping and hiking in the Black Rock Range. So we planned it just as an informal familiarization tour, without pressure to try to see more of the area than we could in that time.

Bob saw the places we've explored. He taught us more about the details in the widespread "thinly-sliced" fractured rocks as I dubbed them. Rather than the ubiquitous small fractures we had noticed, he was more interested in the jointing (bigger straight and parallel fractures) which were clearer evidence of stresses to which the rocks had been subjected.

And Bob also wanted to look at the nearby structures which appeared like volcanic necks along the Black Rock Range. These turned out to be clearly containing breccia, not lava. Bob concluded the USGS geological map of the Black Rock Range, which marked these places as basalt (a form of lava), may have been made too hastily and needed to be reviewed. In an impact crater scenario, breccia would be consistent with debris that fell down in the cracks in the crater floor and formed new jumbled rocks. That idea needs further testing. But so far what appered from a distance to be a volcanic neck but up close turned out not to look like a volcano is geologically very interesting!

So we still haven't found "smoking gun" level of evidence. But with the first visit from an impact specialist, the trend of the observations continues to point away from a volcanic origin and remains consistent with characteristics of an impact site. So even for an informal tour, I couldn't have been more pleased with the results.
Photos from Sept 6 and 27: rocks which we flagged for further investigation as possible coarse-grained/poorly-formed shatter cones. These were taken more than a mile apart.

The search for elusive shatter cones

The primary object of this search has been to look for shatter cones. That's a rock formation with repeating conical branching fractures of large and small scales. They are evidence that the rocks had been exposed to a shock with pressure beyond what the biggest volcano can produce, and is evidence of an impact. If we find well-formed shatter cones, then we won't have any problem convincing geologists to help with electron microscopes to find the microscopic shock features which prove an impact - if you find shatter cones then you know those are also there.

I have two photos on the right from locations more than a mile apart. These are among the best examples so far. For example, the Sept 6 photo (on the left) shows an area where a cone was broken away and reveals more of the same pattern underneath. This is a requirement for recognizing shatter cones - the pattern is 3 dimensional within the rock, not just weathering or marking on the surface.

It isn't difficult to find stuff like this all over the place around there. With the exploration from 2008, we're getting a better picture for the layout of the rock structures in the area. These aren't good enough to claim to have found shatter cones. They do appear good enough to give us the confidence to keep looking for better ones.

Comparison with a confirmed impact site

I didn't just leave it to an assumption. I needed to test the idea whether poorly-developed shatter cones may be indicative of better ones nearby, and whether these look like the ones outlying a confirmed impact site. So I went to Santa Fe, New Mexico on Sept 13-14 to look at the Santa Fe impact structure. It was discovered in 2005 and published in papers in 2007-2008. New Mexico Hwy 475, which is the road from Santa Fe to its ski area, has a one-mile section where there are shatter cones at the side of the mountain road. No one noticed what the shatter cones were for decades, until a geologist noticed a few years ago.

In my observations, the best shatter cones along Hwy 475 were for more like a half-mile stretch, with gradually decreasing quality for a mile either side of that. The observations there in a confirmed impact site agreed that lower quality shatter cones and then similar features to shatter cones can be found in an area outward from the highest quality shatter cones.

I posted my photos from NM on my web site.

I needed to know an answer to that one way or another. So far it shows we're on the right track at Black Rock. Seeing recurring patterns that have some features like shatter cones, such as lots of apex patterns in the rocks, does indeed support the idea of looking for better samples nearby.

Fine- vs. coarse-grained rocks affect shatter cone quality

One thing to keep in mind in the search for better shatter cones is that the type of target rock also dictates the quality of the striations. Shatter cones form best with fine striations in fine-grained rocks. In New Mexico, I saw shatter cones with textbook-quality fine striations next to different kinds of rock with coarse striations. Although even some of the coarse samples in NM were striking.

So at Black Rock, the area where it might be possible to find high quality shatter cones is affected by the grain of the target rocks, as well as the amount of erosion in the area. Mountains of rocks have been eroded away and aren't there any more.

The plan for 2009

With fuel prices back down again, hopefully we'll get more chances to explore at Black Rock than the total of 3 days we got this year. The progress from 2008 is so encouraging that we should have no problem finding the motivation to keep looking. The more places I've seen varying rocks that resemble shatter cones, the more ideas I've gotten on places to go hiking to look next.

There has also been discussion of how to access electron microscopes and what samples to bring to one. Showing around a geologist has helped open some doors there.

Questions and Answers

I'll address some questions here which should help add some details to the current status of the research.

There are no published papers on this - how can anyone believe it?

Let's not put the cart before the horse. If/when we have good enough evidence, it will be time to write papers. Until then, my purpose in posting it on my web site is to find people with similar interests who would like to help.

I haven't initiated contacts with the media. Although others submitted it to some web news sites. And for the article in Discover Magazine, they contacted me for an interview. I'm not turning these down - so far the attention does attract more helpers each time.

This seems to me to be the best I can do to move the research forward with available resources.

Is there a precedent for a large impact crater being discovered by an amateur geologist?

Yes, the Keurusselkä impact structure in central Finland was discovered by amateur geologists in 2003. They co-authored the papers about the structure along with professional geologists. It is now accepted as confirmed by the scientific community.

Keurusselkä bears some similarity to Black Rock in that the structure is so old and eroded that it was no longer obviously visible in the landscape. Its age and diameter are still not known. Estimates place that impact site between 10-30km in diameter and at least 1.88 billion years old.

The photos of columnar jointed rocks aren't convincing - are you aware volcanoes do that too?

Yes, I even said that in the original write-up. When I hear this or see the comment online, it tells me that the commenter isn't interested and only looked at the pictures. That's fine - but I'm only focusing on who's interested right now because those are who might help me with the search for more evidence. I understand that there are skeptics who will not be convinced until we find enough evidence to publish peer-reviewed papers. The only thing to do about that is keep looking.

An interesting point is that we see these columnar jointed rocks at Black Rock at an elevation of around 4450 feet. Since they are all nearly the same elevation across the east and west sides of the playa (25 miles apart), it's an indicator of the possible impact melt pool in the suspected crater. It seems an extremely unlikely coincidence for a volcano to make a lava pool so big or to line up the elevations of similar but unrelated formations so closely. It also gives us an estimate of what elevation the crater floor might have been. That's about 500 feet above the current Black Rock playa. It goes to show how much of the suspected crater has been eroded away.

As the picture has been coming together, the lower Black Rock Range south of Big Mountain/Pahute Peak appears to be a remnant of the suspected crater floor.

The 30x40 mile ellipse seems problematic for an impact - how sure are you about that?

I need to back off on trying to claim too exact an outline. It doesn't matter much at this stage anyway.

It's really hard to tell since it's so old and mostly eroded away. (If it was easy, someone would already have noticed.) It was a case where I wanted to let the observations lead the way whether they were convenient or not. So I posted what I observed. But with another 2 years of looking at the maps, a 40 mile circle also can't be ruled out.

A good example of where these changes are evident is along Jungo Road (Old Hwy 49) on the east side of the playa. Going north from Empire, the rocks in the Selenite Range near the road are initially very solid and do not exhibit fracturing. But from Old Razorback Mountain (a.k.a. The Elephant) near Trego, the rocks are deeply fractured all the way up to Sulphur, after which the road leaves the suspected crater outline to the east.

The likely scenario now looks like the diameter is a question that someone will get their PhD in Geology from doing the research to find that answer.

Update: It looks like I spoke too soon. Less than 3 weeks later I found a succession of terrain features that make a fragmented 54-mile diameter circle around the region, much larger than we were originally looking for. The 30-mile feature now appears not to be the rim but rather a concentric uplift ring within the larger circular structure. Concentric rings on such a large scale contribute to evidence pointing toward an impact.

How old is the suspected crater?

Considering the amount of erosion, how little of it is left, it's a comfortable guess that its age would be in the millions of years. Beyond that, it's another question that someone will probably get their PhD in Geology from getting that answer.

Where is the meteor? Could the Black Rock itself be part of it?

No. Don't expect that there's anything intact. Some impact melt rocks would be expected to come from the target rocks and remains of the impactor.

Impact specialists estimate no more than 10 percent of an impactor would remain as unmelted fragements. Those would have been carried away before the mountainous crater rims were eroded through.

When impactors come from elsewhere in the solar system, they're in orbit around the Sun just like the Earth is. The speed at which such objects collide would usually be in excess of 25,000 mph relative to the Earth, sometimes significantly more. A collision at that speed is enough to melt and evaporate the impactor. Turning a large rock into gas expands its volume so explosively that it excavates a crater many, many times larger than the impactor itself.

The explosion from an impact is so large and violent that they make the biggest nuclear weapons look tiny in comparison. For example, when the comet Shoemaker-Levy 9 collided with Jupiter in 1994, the Hubble Space Telescope recorded pictures of fireball plumes rising from Jupiter which were larger than Earth's Moon and visible scars on Jupiter's clouds which were wider than the Earth. That was the wakeup call for the world that impacts are real.