Map of North Asia ( Click the map to enlarge it! )
North Asia or Northern Asia is a subregion of Asia, consisting of the Asian portion of Russia. The term is not widely used. The Phillips Illustrated Atlas of the World 1988 defines it as being most of the former USSR, the part that is to the east of the Ural Mountains. A definition pre-dating the USSR is an 1882 one by Keane and Temple, who defined it as "the two great administrative divisions of West and East Siberia, whose capitals are Omsk and Irkutsk respectively". It was, according to them "one vast political system, comprising nearly one-third of the whole continent, and, with a few trifling exceptions, directly administered by Russia".
There are no mountain chains in Northern Asia to prevent air currents from the Arctic flowing down over the plains of Siberia and Turkestan.The plateaux and plains of Northern Asia comprise the West Siberian lowlands; the Angara Shield, with the Taimyr Peninsula, the coastal lowlands, the Putorana Plateau, the Anabar Plateau, the Tunguska Plateau, and the Angara Plateau; and the Lena-Vilyuy Basin.
During pre-Islamic and early Islamic times, Central Asia was a predominantly Iranian region that included sedentary Sogdians, Chorasmians and semi-nomadic Scythians, Alans. The ancient sedentary population played an important role in the history of Central Asia. After expansion by Turkic peoples, Central Asia also became the homeland for many Turkic peoples, including the Uzbeks, Kazakhs, Kyrgyz, and Uyghurs, and Central Asia is sometimes referred to as Turkestan.
The geomorphology of Asia in general is imperfectly known, although the deposits and mountain ranges are well known.
To compensate for new sea floor having been created in the Siberian basin, the whole of the Asian Plate has pivoted about a point in the New Siberian Islands, causing compression in the Verkhoyansk mountains, which were formed along the eastern margin of the Angara Shield by tectonic uplift during the Mesozoic Era. There is a southern boundary to this across the northern margin of the Alpine folds of Iran, Afghanistan, India, Nepal, and Bhutan, which at the east of Brahmaputra turns to run south towards the Bay of Bengal along the line of the Naga hills and the Arakan Yoma, continues around Indonesia, and follows the edge of the continental shelf along the eastern seaboard of China. The Eurasian Plate and the North American Plate meet across the neck of Alaska, following the line of the Aleutian Trench, rather than meeting at the Bering Straits.
Northern Asia is built around the Angara Shield, which lies between the Yenisey River and the Lena River. It developed from fragments of Laurasia, whose rocks were mainly pre-Cambrian crystalline rocks, gneisses, and schists, and Gondwana. These rocks can be found in the Angara Shield, the Inner Mongolian-Korean Shield, the Ordes Shield and the South-East Asia Shield. The fragments have been subject to orogenesis around their margins, giving a complex of plateaux and mountain ranges. One can find outcrops of these rocks in unfolded sections of the Shields. Their presence has been confirmed below Mesozoic and later sediments.