LESSER KHINGAN RANGE

WadeGiles romanization Hsiao Hsing-an Ling, Pinyin Xiao Hinggan Ling, mountain range in the northeastern section of Heilungkiang sheng (province), China. The range is connected to the Greater Khingan Range by the I-lo-hu-li Mountains, which run northwestsoutheast for some 375 miles (600 km), extending southwest of the Amur River until, beyond the Sungari River, in the area of Chia-mu-ssu, they merge into the eastern Manchurian mountain system in the Wan-ta Range. Although they share the same name, the Lesser Khingan Range is a completely different mountain system from the Greater Khingan Range. The Greater Khingan Range is largely composed of rocks that are igneous (formed from the molten state) and metamorphic (formed under conditions of heat and pressure) and was formed in the Jurassic Period, whereas the Lesser Khingan was until Quaternary times a part of the great intermontane trough formed by the Manchurian and Zeya-Bureya plains. The range was formed by the uplift of its comparatively young sedimentary rocks in comparatively recent geologic times. The relief is generally rounded and gentle, the main sharp fault line running along the Amur Valley, giving the northeastern face a somewhat sharper contour than the southwest, which merges gently into the Sungari plain. The range forms a watershed between the Amur River system and the Sungari and Nen River system. The Lesser Khingan is lower than the Greater Khingan and has elevations averaging between 1,650 and 3,300 feet (500 and 1,000 m), with most of the range being less than 2,000 feet (600 m). The Lesser Khingan's climate is slightly more temperate and much more humid. Winters, nevertheless, are still long and bitterly cold, and much of the area is under permafrost. The whole area is covered with timber, mostly consisting of larch and birch in the north, and of mixed broad-leafed and coniferous forests (cedar, spruce, yew, birch, elm, and larch) in the south. Forestry is the main economic base, and in the southern part of the range a number of railways, centring on Nan-ch'a and I-ch'un, have been constructed to transport lumber. The southern end of the range is marked by the great fault line of the Sungari River valley. The name Lesser, or Outer, Khingan (Wai Hsing-an) is also given by the Chinese to ranges in Russia, to the north of the Amur, in the region of Birobidzhan.