Winters on the West Siberian Plain are harsh and long. The climate of most of the plain areas is either subarctic or continental. The plain had largepetroleum andnatural gas reserves. Most of Russia's oil and gas production was extracted from this area during the 1970s and 80s.[1]
The West Siberian Plain is located east of theUral Mountains mostly in the territory ofRussia. It is one of theGreat Russian Regions and has been described as the world's largest unbrokenlowland – more than 50 percent is less than 100 m (328 ft) above sea level[2]—and covers an area of about 2.6–2.7 million square kilometres (1.0 million square miles) which is about one third of Siberia.[1] It extends from north to south for 2,500 kilometres (1,600 miles), reaching its maximum width of 1,500 kilometres (930 miles) in its southern part.[3] from theArctic Ocean to the foothills of theAltai Mountains, and from east to west for 1,900 km (1,181 mi) from theYenisei River to theUral Mountains. Besides the Yenisei, other main rivers in the West Siberian Plain are from west to east theIrtysh,Ob,Nadym,Pur andTaz. There are many lakes andswamps and large regions of the plains are flooded in the spring.
The long Yenisei River flows broadly south to north, a distance of 3,530 km (2,193 mi) to the Arctic Ocean, where it discharges more than 20 million litres (5 million gallons) of water per second at its mouth. Together with its tributary Angara, the two rivers flow 5,530 km (3,436 mi). The valley formed by the Yenisei acts as a rough dividing line between the West Siberian Plain and theCentral Siberian Plateau.[4] TheSiberian Uvaly is a low hilly region stretching from east to west across the plain.[5] Glacial deposits extend as far south as the Ob-Irtysh confluence, forming occasional low hills and ridges, including theOb Plateau in the south,[6] but otherwise the plain is exceedingly flat and featureless. TheIshim Plain and theBaraba Lowland in the south are important agricultural areas.[7] There are salt lakes in theKulunda Plain, which extends southwards intoKazakhstan and is limited to the south by theKokshetau Hills.[8]
The West Siberian Plain is veryswampy and soils are mostlypeatyHistosols and, in the treeless northern part,Histels. It is one of the world's largest areas of peatlands, which are characterized byraised bogs. TheVasyugan Swamp that covers most of theVasyugan Plain is one of the world's largest single raised bogs, covers approximately 51,600 square kilometres (19,900 sq mi). There are numerous lakes in the vast interfluve swamps of the Ob-Tazfloodplain.[3]
The plain has eight distinct vegetation regions:tundra,forest-tundra, northerntaiga, middle taiga, southern taiga, sub-taiga forest,forest-steppe, andsteppe. The number of animal species in the West Siberian Plain ranges from at least 107 in the tundra to 278 or more in the forest-steppe region. In the south of the plain, wherepermafrost is largely absent, richgrasslands that are an extension of theKazakh Steppe formed the original vegetation, which had almost all been cleared by the early 21st century.
The West Siberian Plain consists mostly ofCenozoicalluvial deposits and is extraordinarily flat. A rise of fifty metres insea level would cause all land between theArctic Ocean and theOb-Irtysh confluence nearKhanty-Mansiysk to be inundated (see alsoTurgai 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 fromice dams that reversed the flow of theOb andYenisei rivers, redirecting them into theCaspian Sea, and perhaps theAral Sea as well.
