Ural Mountains - geography.

Ural Mountains - geography. Ural Mountains (Russian Ural'skiye Gory), mountain chain in Russia, extending 2,400 km (1,500 mi) from its northern boundary at the Arctic Ocean to its southern limits at the steppes of Kazakhstan, traditionally separating the continents of Europe and Asia. The chain is divided roughly into four main divisions: the Polar, Northern, Middle, and Southern Urals. The Polar Urals (above latitude 64° North) are treeless arctic tundra. The Northern Urals (latitude 64° North to latitude 61° North) constitute a distinct craggy, treeless, narrow range with crests averaging 300 to 500 m (1,000 to 1,500 ft) in height. This range contains the highest Ural crest, Gora Narodnaya (1,894 m/ 6,214 ft). Other Northern peaks include Mount Sablya, Telpos-Iz, and Isherim. The only trees in the area are sparse growths of larch (a type of pine tree). Numerous plateaus, characterized by broad, flat, marshy valleys, extend in a southwestern direction from the southern limits of the Northern Urals. The entire Middle Ural region (latitude 61° North to latitude 60° North) is covered with dense coniferous forests. A succession of northeastern mountain chains marks the northern boundary of the Middle Urals. The southern boundary is marked by numerous hills of 300 to 600 m (1,000 to 2,000 ft) separated by deep ravines. The Konzhakovskiy Kamen, 1,571 m (5,154 ft) high, is the highest peak of both the northern and southern portions of the Middle Urals. Dense forests, rich soils, and fertile valleys cover the entire area. South of the Middle Urals (latitude 55° North to latitude 51° North) are three parallel mountain chains called the Southern Urals. The first of these, the Urals proper, is a low chain ranging in height from 670 to 850 m (about 2,200 to 2,800 ft). To the west, a higher range, containing many rivers, reaches a height of 1,594 m (5,230 ft) and is paralleled farther west by an equally high range. All three ranges are heavily wooded with deciduous plant life and contain rich pasturelands. The Urals continue from latitude 51° North toward the Volga River and, under the name of Obshchiy Syrt, comprise a system of plateaus reaching 460 m (1,500 ft) in height and 320 km (200 mi) in width. South of the Ural River, the Ural chain appears as a group of independent ranges. Geologically, the Urals are the worn-down stumps of an ancient range that rose toward the end of the Paleozoic era, 250 million years ago (see Permian Period), while the American Appalachian Mountains were forming. The divisions of the range reflect distinct episodes in this ancient upheaval, which squeezed thick sedimentary rock layers into large northern-southern trending folds, then faulted and intruded them with a variety of igneous rocks. Important industrial areas are located in the Middle and Southern Urals. Intensive industrialization in the former Union of Soviet Socialist Republics (USSR) began during World War II (1939-1945), when many industries were established to develop armaments production centers far from the military zone. The region has been a major center of nuclear weapons production since 1948, when the Mayak complex began operations near the city of Kyshtym. Mayak produced the material for the first Soviet atomic bomb, detonated in August 1949. Mayak caused three major incidents of nuclear waste contamination in 1949, 1957, and 1967, which combined released more than ten times the radiation of the world's worst known reactor disaster near Chernobyl', Ukraine. In the 1950s nuclear wastes from Mayak were diverted into nearby Lake Karachai, and the lake soon became highly radioactive. In the late 1960s workers began filling in the lake with rock and soil and planned to seal it over with concrete by the mid-1990s, but a government commission concluded in 1991 that this might force radioactive isotopes into the groundwater. Containment of radioactive wastes and cleanup efforts continue in the Urals amid public controversy over how best to proceed. The Ural region has extensive deposits of iron ore and coal in close proximity, as well as rich deposits of chromium, manganese, copper, zinc, bauxite, platinum, silver, and gold. Just to the east of the Urals is a major oil-producing area. Among the important industrial cities are Magnitogorsk, Yekaterinburg, Chelyabinsk, Perm', and Nizhniy Tagil. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.