URAL

URAL, Ural Mountains, Ural mountain system, Ural folded region, mountain country, stretched in meridional direction from the coast of the Kara Sea to the latitudinal flow of the Ural River. The length is more than 2,000 km, width is 40—60 km (in some places up to 100 km). In the SW, through the Pai Khoy Ridge and Vaygach Island U. passes into the mountains of the Archipelago Novaya Zemlya, in the S. its continuation is the Mountains of Mugodjary. Natural boundaries of U. coincide with the morphostructural ones, where abrupt changes in the nature of all the components of natural conditions are observed. The eastern border coincides with the tectonic lump on contact with the quaternary deposits of the Western Siberia; the western border is less clear, well‑expressed in the Northern and Middle Urals, and it passes along the Pre‑Urals foreland basin. U. is a complex of linear folded area, within which rocks are exposed by age from Archaean (over St. 3 billion years) to the present. In the vertical and age measurement, the natural complexes that make up U. are divided into structural tiers: intensely folded and deeply metamorphized Archaean‑Proterozoic; Riphean‑Vendian (development ended with the formation of a folded region of thimanides); Paleozoic‑early Mesozoic (corresponds to the development of a folded belt of uralides); middle Jurassic‑Miocenic platform (associated with the peneplanation of territory); Pliocene‑quartenary neoorogenic (caused by the formation of modern. U.). Uralides are represented most fully and variably. In the northern U. their eastern zones are submerged under the cover of the West Siberian basin. The geological structure features the Pre-Urals foreland basin, filled with flysch and molasses of the Permian system; the Western Ural folding zone, built with shallow water and deep water deposits of the Paleozoic continental margin; the Central Urals zone, in which the ancient complexes of Proterozoic stages are bared; the Tagil-Magnitogorsk zone — the complexes of the bottom of the Paleozoic Paleo‑Ural Ocean and the island arcs, developed in it; the Eastern Urals zone with the basement of the Proterozoic Microcontinent, overlapped with the Paleozoic deposits of various types and permeated with large quantities of granitic intrusions; the Trans-Urals zone, whose complex structure is comprised of continental, oceanic and island‑arc complexes. U. is rich in minerals, especially in the deposits of non‑metallic minerals, deposits of ore minerals, gold placer and ore, facing stones, etc. Oil and gas fields are known in the advanced folds and reef masses of the Pre-Urals foreland basin. The orographic elements are caused by the orientation of geol. structures. In the extreme N. there is Pai‑Khoy — low (up to 467 m) slightly hilly upland, to the south of which there lies Zapolyarny U. Abs. alt. over 1,000 m. The Polar U. begins to the south of the Sob-Yelets passage. Nether-Polar U. stretches from the upper reaches of the Hulga River (basin of the Ob River) to the Shugor River (basin of the Pechora River). Vast high plateaus prevail with towering ridges. Narodnaya mountain (1,894 m), the highest peak of U., is located on the Issledovatelskiy Ridge. The Northern U. begins from the latitude of Telposiz Mountain (1,617 m) and ends at the latitude of Konzhakovskiy Kamen Mountain (1,569 m). On this stretch U. runs along meridian 59° E with 3 flat‑topped ridges, the center is known as Belt Stone (Oika-Chakur Mountain — 1,322 m). The Middle U. stretches from 59° to 55° N (Yurma Mountain — 1,003 m). Max. alt. — 878 m (Kachkanar Mountain). The Southern U. stretches from 55° 25′ N to the latitudinal segment of the Ural River and is divided into the northern mountainous and southern plateau-like parts. The width of the mountainous p. reaches 120 km. It is represented by several rows of ridges, of which Uraltau is a watershed. Max. alt. of the S.U. — Yamantau Mountain (1,640 m). To the south of the latitudinal stretch of the Belaya River there is a general drop of heights: the South Ural peneplain (Zilair Plateau) is clearly expressed here; in the E. the axial part of the South. U. passes into the Trans‑Ural peneplain — a lower and smoothed out plain.