Western Siberian lowland (English name: Zapadno-Sibirskaya nizmennost')

Japanese: 西シベリア低地 - にしシベリアていち（英語表記）Zapadno-Sibirskaya nizmennost'

A vast lowland in Western Siberia, central Russia. It is also called the West Siberian Plain (Zapadno-Sibirskaya Ravnina). It faces the Kara Sea to the north, is bounded by the Ural Mountains to the west, the Yenisei River to the east, and the Turgai Plateau, Kazakh Hills, and Altai Mountains in Kazakhstan to the south. It stretches 2,500 km from north to south, and is 1,000 to 1,900 km wide from east to west. Its area is about 2.6 million ^km2 . The Ob River runs through the center from southeast to northwest, and most of it is in its basin. Its elevation is 50 to 150 m, and although there are moraine hills in the north, the rest of the area is very monotonous flat land. It is made up of Mesozoic to Cenozoic Paleogene strata that show nearly horizontal deposition, and its surface is covered with loess in the south and postglacial sand and clay in the north. The northern part is tundra, the central and southern parts are forested, and the southern edge is forest steppe and steppe. Annual precipitation is about 500 mm in the central part, but 200-300 mm in the northern and southern parts. Many areas are flooded by heavy floods from spring to early summer, especially the Bashuganie Marsh in the southern part, which is flooded for 2-3 months and cuts off transportation. In recent years, underground reserves of oil and natural gas have been discovered, and large-scale development has begun in the Tyumen oil field and other areas. Cities such as Novosibirsk, Omsk, Tyumen, Kurgan, and Tomsk are located along the main line and branch lines of the Trans-Siberian Railway that runs through the southern part, but many areas in the central and northern parts have no transportation other than by car or plane, and many areas have to rely on small boats and sleds.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

ロシア中部，西シベリアにある広大な低地。西シベリア平原 Zapadno-Sibirskaya ravninaともいう。北はカラ海に面し，西はウラル山脈，東はエニセイ川，南はカザフスタンのトゥルガイ高原，カザフ丘陵，アルタイ山地によってかぎられる。南北 2500kmにわたり，東西の幅は 1000～1900km。面積約 260万 km²。中央部をオビ川が南東から北西へ貫流し，大部分がその流域に属する。標高は 50～150mで，北部にはモレーン（氷堆石）の丘陵が見られるが，そのほかのところはきわめて単調な平地が続く。水平に近い堆積状態を示す中生代～新生代古第三紀の地層からなり，表面は南部ではレス，北部では後氷期の砂，粘土などで覆われる。北部はツンドラ，中・南部は森林地帯，南縁部は森林ステップ，ステップ地帯に入る。年降水量は中部では約 500mmであるが，北部と南部では 200～300mm。春～初夏の大水により浸水する部分が多く，特に南部のバシュガニエ湿地では2～3ヵ月間冠水し，交通が途絶する。近年，地下資源として石油，天然ガスを埋蔵することが発見され，チュメン油田そのほかで大規模な開発が始まった。南部を走るシベリア横断鉄道の本線，支線に沿ってノボシビルスク，オムスク，チュメン，クルガン，トムスクなどの都市があるが，中・北部には，自動車，航空機以外に交通の便のない地域が多く，小舟，そりによるしかない地域も少なくない。

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