Ishim Formation serves as a regional stratotype of the southwestern part of the West Siberian Plain (Tobol-Ishim interfluve), which recorded the sedimentation conditions close to Miocene-Pliocene boundary.
The southern part of the West Siberian Plain is characterized by the three-unit structure: the lower level is composed of highly dislocated metamorphosed sedimentary and effusive-sedimentary Paleozoic rocks; the second level is composed of dislocated continental Triassic-Jurassic sometimes coal-bearing deposits, filling the submeridional narrow depressions emplaced on the Paleozoic basement.
The Ishim Formation or deposits of Ishim sedimentary rhythm are well distributed within the Ishim-Irtysh and Tobol-Ishim interfluves of the West Siberian Plain. This formation was distinguished for the first time by V.A.
By the Early Miocene a lacustrine basin, which occupied the vast territory in the West Siberian Plain in the Late Oligocene, had reduced (Shatsky, 1978).
and Konstantinov, A.O.: 2016, New palynological data from Upper Miocene Ishim Formation (section Masali, West Siberian Plain).
The longest SCD of more than 70 days occurs over the West Siberian Plains, the Taymir Peninsula, and the Canadian archipelago and in mountain areas.
The largest snow cover in HIRHAM5 is found over the west Siberian plains and the Taymir Peninsula, the Kolyma River basin, and the Canadian archipelago.
It is a geographical region located around the Ural Mountains, between the East European and West Siberian plains
. It extends approximately from north to south, from the Arctic Ocean to the bend of the Ural River near Orsk city.