West Siberian Plain

The West Siberian Plain is a massive lowland located in North Asia. It sits within the western portion of Siberia, mostly inside the territory of Russia. This region is bounded by the Ural Mountains to the west and the Yenisei River to the east. To the southeast, the Altai Mountains mark another boundary.

Scientists describe it as the world's largest unbroken lowland. More than 50 percent of the plain sits at or near sea level. It covers an area of about 2.6 million square kilometers. This makes the plain roughly one third of the total size of Siberia.

The physical geography of the plain is defined by its extreme flatness. Most of the land is exceedingly flat and featureless. However, some specific geological features do exist. The Siberian Uvaly is a low, hilly region that stretches from east to west. Glacial deposits also create occasional low hills and ridges. One such example is the Ob Plateau located in the southern part of the plain.

The plain is also shaped by long-term geological processes. It is a region of the Earth's crust that has undergone prolonged subsidence. The area is composed of horizontal deposits that date back as much as 65 million years.

Water plays a vital role in the structure of this landscape. Many large rivers flow across the plain from west to east. These include the Irtysh, Ob, Nadym, Pur, and Taz rivers. The Yenisei River serves as a major boundary to the east. It flows south to north for a distance of 3,487 kilometers. At its mouth, the Yenisei discharges more than 20 million litres of water per second into the Arctic Ocean.

In the spring, large regions of the plains are flooded. This creates vast floodplains and many large lakes.

Because of this water, the West Siberian Plain is very swampy. Much of the land consists of some of the world's largest swamps. The soils are mostly peaty, known as Histosols or Histels in the treeless north. The plain contains one of the largest areas of peatlands on Earth. These peatlands are characterized by raised bogs. A notable example is the Vasyugan Swamp. It covers the Vasyugan Plain and spans approximately 50,000 square kilometers. This makes it one of the largest single raised bogs in the world.

The vegetation of the plain is divided into eight distinct regions. These include the tundra, forest-tundra, and three types of taiga. The middle taiga, southern taiga, and sub-taiga forest also exist here. Moving south, the landscape changes to forest-steppe and then to steppe.

Animal life follows these different vegetation zones. The number of species varies by region. The tundra contains at least 107 animal species. In contrast, the forest-steppe region supports 278 or more species. In the south, rich grasslands once grew as an extension of the Kazakh Steppe. Most of these grasslands were cleared by the early 21st century.

Human activity is closely tied to the resources found in this region. The plain holds large petroleum and natural gas reserves. During the 1970s and 1980s, most of Russia's oil and gas production was extracted from this area. Several important cities are located on the plain. These include Chelyabinsk, Novosibirsk, Omsk, and Tomsk. Other significant cities are Surgut and Nizhnevartovsk. The climate can be difficult for inhabitants. Winters are long and harsh, with most areas having a subarctic or continental climate.

The geology of the plain provides clues about the Earth's past. Many of the deposits resulted from ancient ice dams. These dams once reversed the flow of the Ob and Yenisei rivers. This redirection sent water toward the Caspian Sea and perhaps the Aral Sea. The landscape is so low that it is highly sensitive to sea level changes. If the sea level rose by fifty metres, the land between the Arctic Ocean and the Ob-Irtysh confluence would be inundated. This would submerge the area near Khanty-Mansiysk under water.