linguistic:translation, stylistic:tone
Geology

The West Siberian Plain consists mostly of Cenozoic alluvial deposits and is extraordinarily flat. A rise of fifty metres in sea level would cause all land between the Arctic Ocean and the Ob - Irtysh confluence near Khanty-Mansiysk to be inundated (see also Turgai Straits, West Siberian Glacial Lake). It is a region of the Earth's crust that has undergone prolonged subsidence and is composed of horizontal deposits from as much as 65 million years ago. Many of the deposits on this plain result from ice dams that reversed the flow of the Ob and Yenisei rivers, redirecting them into the Caspian Sea, and perhaps the Aral Sea as well.