This photograph, taken in 1995, shows a Middle to
Upper Paleolithic site in eastern Siberia called the
Tolbaga stie. The Russian archaeologist is standing
on the surface of a 43,000 year old Mousterian site and
pointing to a 23,000 year old Aurignacian stratum. Note
the Aurignacian layer and how it undulates. This type
of soil movement is one indicator of cold climate geology.
The dark soil layer above the undulating lighter colored
thermo-clastic layer belongs to the Duyktai or Dyktai
micro-blade industry which dates to 19,000 years ago.