a mountain system in Eastern Siberia, stretching from the northern end of Lake Baikal to the middle course of the Olekma River. It is about 700 km long and more than 200 km wide. Rising to 3,000 m and trending east-northeast, the ranges alternate with intermontane basins whose floors lie at 500–1,000 m. The highland is part of the vast Svodovoe Uplift, composed chiefly of crystalline and metamorphic Archean and Proterozoic rocks. The basins are filled with thick strata of Ceno-zoic sediments. Contemporary relief-forming processes are intensive owing to the region’s high seismicity, ubiquitous permafrost, and rugged terrain. Mineral resources include gold, copper, fluorite, and coal. Characteristic of the ranges are such alpine relief forms as rocky crests, sharp peaks, cirques, and U-shaped valleys. The flat summits of the relatively snowless ranges have alti-planation terraces.
The climate is harshly continental. In the basins summers are warm and last two or three months. In the high mountains they are cool and of short duration (less than a month in places). Winters are very long and cold, with little snow in the basins. Precipitation varies from 300–400 mm a year in the basins to 1,000 mm in the mountains; more than 60 percent of it falls in the latter half of the summer. Temperature inversions are typical. There are small glaciers.
The river network is dense, and the rivers are partially fed by meltwater. The region has many lakes, which are especially numerous in the basins. The slopes of the ranges are covered with larch taiga. Above 1,200 m are found sparse larch woodlands, giving way to bald peaks. The basin floors are occupied by marshy floodplain meadows; pine and pine-larch forests grow on the thick sand deposits.
REFERENCESPredbaikal’e i Zabaikal’e. Moscow, 1965. (ANSSSR: Prirodnye usloviia i estestvennye resursy SSSR.)
Nagor’ia Pribaikal’ia i Zabaikal’ia. Moscow, 1974.
L. I. MUKHINA