As part of a weekend trip out to eastern Umnugovi Aimag with friends from Khankhongor Soum, the school driver from Khanbogd Soum (a mutual friend) led our group out to an interesting geological formation about 30km from the soum center. He emphasized to me several times that few people knew about the place, and everyone in the Khankhongor contingent confirmed this by repeating several times they had never even heard of the place let alone had visited it previously.
I am not a geologist, so I could only marvel at the site and wonder how it was formed. The rock looked like a cross between granite and crystalline concrete. It was very rough and it easily broke under modest pressure. It looked as though the rock formed initially under a sedimentary process, and then later the area was shaped by some sort of erosive force. I was compelled based on intuition and knowledge barely remembered from a geology class I took over ten years ago in college to think that it formed under the influence of water. It had several hallmarks of water erosion, especially pock marks born into the sides of boulders. But, that would suggest that a very large sea or other body of water with currents was present at the location at some point in its history, and I am not sure if there was such a body of water in the Gobi. The hypothesis therefore has an obvious flaw, and I remain ignorant of the true cause of the formations.
If there are any geologists out there reading this with ideas, please do offer comments. It was a truly interesting place.