Dzungarian Alatau

(redirected from Dzungarsk-Alatau Mountains)
Also found in: Wikipedia.

Dzungarian Alatau

 

a mountain system lying chiefly in the USSR (in the southeastern part of the Kazakh SSR) and partially in China, between Alakol’ Lake and the Hi River. The system extends in a southwest-northeast direction for almost 450 km and has a width ranging from 50 to 190 km. It consists of several parallel ranges, including the Karatau, Baskantau, Toksanbai, and Bedzhintau. Massifs ranging from 1,500 to 3,000 m in elevation predominate. The highest elevation is 4,464 m (Mount Besbaskan).

In the north the Dzungarian Alatau is composed of sandstones, aleurolites, and schists of the Devonian and Carboniferous periods and in the south of igneous rock of the Carboniferous and Permian periods. In the central part there are outcrops of more ancient crystalline rocks. The Dzungarian Alatau has deposits of complex ores, copper, and rare metals. The topography, formed primarily as a result of Cenozoic tectonic movements, consists of alternating mountain ranges and intermontane basins divided by steep tectonic scarps. The numerous outliers of ancient denudation surfaces in the low- and mid-mountain massifs give the topography a step-like appearance. In the central part of the system, the mountains rise above the snow line; there are glaciers covering a total area of 1,120 sq km. The largest glaciers are on the northern slope (the 5.5-km-long Dzhambul glacier and the 8-km-long Berg glacier). With altitude changes the following alternation of landscape zones occurs: the piedmont deserts and the semideserts give way first to dry and then to chernozem steppes in the low-mountain massifs; the steppes in turn yield to forest-meadow or forest-meadow-steppe landscapes in the midmountain ranges. Typical of the uplands are subalpine-meadow-brush, alpine-meadow, subnival, and nival landscapes. The northern and southern slopes of the Dzungarian Alatau are marked by variations in the structure of the altitude zonality and by differences in the altitude positions of the boundaries of analogous zones. In the uplands the variation in the altitude at which boundaries of the same zones lie ranges from 200 to 400 m and in the low-mountain area the variation increases in places to 1,000 m.

T. S. TIKHONOVA