China

The Tien Shan

The Chinese (eastern) part of the Tien Shan consists of a complex system of ranges and depressions divided into two major groups of ranges: the northern and the southern. The groups are separated by a strip of intermontane depressions that itself is broken up by the interior ranges. Ancient metamorphic rock constitutes the larger portion of the ranges in the interior zone; Paleozoic (i.e., about 250 to 540 million years old) sedimentary and igneous sedimentary beds form its northern and southern chains, while Mesozoic (about 65 to 250 million years old) sandstones and conglomerates fill the intermontane depressions in the interior zone and constitute the foothill ridges. The height of the main Chinese chains of the Tien Shan is between 13,000 and 15,000 feet (4,000 and 4,600 metres), with individual peaks exceeding 16,000 feet (4,900 metres); the interior chains reach 14,500 feet (4,400 metres). In the western part, where precipitation is adequate, large glaciers are formed, reaching a length of more than 20 miles (32 km). Large rivers with heavy flows, such as the Ili (Yili) River and its tributaries, begin their courses there, and the predominantly alpine meadow steppe is one of the best grazing lands of China.

Tian Lake in the Bogda Mountains in the eastern Tien Shan, Uygur Autonomous Region of Xinjiang, China.K. Scholz/Shostal Associates