Greater Khingan - Geography

Geography

The area has an elevation of 1,200 to 1,300 metres, with the highest peak reaches 2,035 metres. The range is much broader in the north (306 km (190 mi)) than it is in the south (97 km (60 mi)). It was formed during the Jurassic Period (roughly 200 to 145 million years ago), and is essentially a tilted fault block; its ancient fault line forms its eastern edge, facing the Northeast Plain. The ranges are markedly asymmetrical, with a sharp eastern face and a more gentle western slope down to the Mongolian Plateau at an elevation of 790–1,000 m (2,590–3,300 ft). The eastern slopes are more heavily dissected by the numerous tributaries of the Nen and Sungari rivers, but generally the mountains are rounded with flat peaks. The ranges are composed largely of igneous rocks (i.e., formed through the solidification of magma).

Dense forests cover the range. This eco-region is noted for its Daurian flora, which has influence from the adjacent Siberian and Manchurian floras. The mountains form an important climatic divide. They take most of the precipitation from the southeasterly winds and produce a comparatively wet climate (precipitation exceeds 500 millimetres (20 in) annually) that contrasts sharply with the arid region to the west. The northern section of the mountains is the coldest part of eastern China, with extremely severe winters (mean temperature −28 °C (−18 °F)) and with large areas under permafrost. Forests of larch, birch, aspen, and pine cover the region with shrubs covering at the highest elevations. The rich and diverse wildlife include deer, elk, marten, hare, and many other fur-bearing animals. However, the central and southern sections of the range have considerably warmer temperatures and drier climates than in the north, with January temperatures of about −12 °C (10 °F), annual precipitation of 250–300 mm (9.8–12 in), and comparatively light snowfalls. The coniferous forests of the north gradually give way in the south to broad-leaved forests and then to patches of grassland interspersed with woodland. In the south, the forests cover the higher ground above 1,500 m (4,900 ft), while tall grasses cover the majority of the area. In May 1987 the devastating Black Dragon fire swept the Da Hinggan forests, destroying perhaps 10,000 km2 (3,900 sq mi) of timber. The Black Dragon Fire gained its name from the Heilong Jiang (“Black Dragon River”; i.e., the Amur) that flows through the area.