The Altan Uul locality was described by Michael Novacek as "a canyon carved out of a very rich series of sedimentary rocks" with "steep cliffs and narrow washes". The climate associated with it was wetter than when preceding formations were deposited; there seems to have existed at least some degree of forest cover.
Michael Novacek described the Altan Uul locality as a canyon carved out of rich sedimentary rocks, featuring steep cliffs and narrow washes.  The climate in this area was wetter than during the deposition of previous formations, suggesting that there may have been some level of forest cover.