Ural-Mongolian Folded Geosynclinal Belt

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Ural-Mongolian Folded Geosynclinal Belt

 

a tectonically mobile belt of the earth’s crust within the Asian continent, stretching from the Urals across Central Asia to the Pacific coast. The Ural-Mongolian folded geosynclinal belt is bounded by the Eastern European Platform on the west, by the Siberian Platform on the northeast, and by the Sino-Korean Platform on the south. In the southwest the belt merges with the Mediterranean geosynclinal belt, and in the east it joins the Pacific geosynclinal belt. The Ural-Mongolian belt includes the folded structures of the Urals, central Kazakhstan, the Tien-Shan, the Altai, the Saian, and Mongolia.

The folded structures of the Ural-Mongolian geosynclinal belt were formed in the course of several tectonic ages. The most important of these ages were the Baikal age at the end of the Pre-cambrian (southern rim of the Siberian Platform), the Salair age, (eastern Altai-Saian region and northern Mongolia), the Caledonian age in the Silurian (central Kazakhstan, Northern Tien-Shan, Altai, and Western Saian), and the Hercynian age in the Late Paleozoic (Urals, Southern Tien-Shan, and the mountains of southern Mongolia). During the Mesozoic, the geosynclinal belt became a young platform. Over time the folding shifted from the Siberian Platform to the southern and western margins of the belt. Whereas the eastern part of the belt, encompassing central Kazakhstan and the Altai-Saian region, has a mosaic pattern of folded structures, the western and southern parts, consisting of the Urals and the Tien-Shan have a linear pattern and extensively developed overthrust nappes.

Intensive magmatism was characteristic of all the development stages of the Ural-Mongolian belt. Magmatic complexes of ultra-basic and basic composition (ophiolites), formed under oceanic conditions, are represented in all the zones. The ancient Paleo-Asiatic Ocean that existed on the site of the belt during the Paleozoic can be reconstructed by the distribution of these rocks. Intrusions of large masses of granite and vast lava flows occurred in the orogenic periods of the Devonian and late Paleozoic. Within the belt there are deposits of iron and coppor ore, gold, lead, zinc, tin, and tungsten. Other resources include platinum, chromium, and coal.

REFERENCE

Tektonika Uralo-Mongol’skogo skladchatogo poiasa. Moscow, 1974.

L. P. ZONENSHAIN

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.