In my earlier posts , If not by impact, then what?, A few craters more, and The Meteorite Men, and The Odessa Crater, I wrote of the numerous small craters in New Mexico, and west Texas. And the question remains essentially unanswered.
Since none of them have been officially confirmed as impact structures, we’ll just call them ‘enigmatic depressions’ for now. I’ve received quite a few emails from folks about what they thought happened to form them. And they proposed every thing from inter-planetary electric discharges, to karst collapses, and oil field blowouts.
But missing from the responses so far, is an answer from a trained geologist, or impact scientist. And in spite of the fact that they are dramatically obvious in satellite image data, I haven’t been able to turn up anything online, or in the literature, that indicates anyone has done any real science at any of them. Although with my limited access to the literature, that may simply be because I haven’t looked in the right places.
I’d like to reiterate the question. But this time I’m hopping to hear a plausible, well thought out, theory from a trained Geologist that describes a non-impact related process for their formation. And if possible, I hope someone can tell me of some honest science that’s been done on them.
They are all in the very same geologic condition. Indicating that they are all close to the same age. And they predominate in surfaces, and terrains, that date to the late Pleistocene.
If they are indeed impact craters, then their very existence, and in such numbers, has a profound effect on impact threat assessment. Because that would mean that impact events that consist of large clusters of smaller fragments do indeed happen. And that they have done so in the geologically recent past. It also means that the ideas that we can assume a steady, and consistent, flux of impacts in the solar system, and that we can estimate the age of a planetary surface by counting the number of craters in any given area become almost childishly naïve.
If they weren’t formed in an impact event, they are none the less significant, and exiting. Because in that case, they demonstrate empirically that there is a geologic process in the solar system that can produce structures which, when viewed in satellite imagery, are visually indistinguishable from impact craters.
And again, the idea that you can estimate the age of a planetary surface by counting the number of craters visible in a satellite image falls apart.
If they’re all karst collapses, and if any given sinkhole is only part of much larger cave system beneath, then we are looking at the upper surface of a vast, inter-connecting, cave system extending over tens of thousands of square miles. And that would make it the largest known cave system in the solar system. Still an amazing, and paradigm shifting, result.
So, again, if those things weren’t formed by impact, then what?
Study the image below closely. Note the over lapping rims in some of them. Overlapping karst sinkholes don’t have raised rims. But overlapping impact craters do.
The image below is the same place in late summer. The red line is 100 meters for scale.
The shear numbers become apparent when you zoom out to about 6 km.