Karakoram(redirected from Karakorum Mountains)
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(Karakorum), a mountain system in Central Asia. The Karakoram are located between the Kunluns in the north and the Transhimalayas in the south. Length, around 500 km; together with their eastern continuation, the Changchenmo and Pangong ranges, which become the Plateau of Tibet, their length is over 800 km. Width, from 150 to 250 km. The Karakoram consist of several parallel ranges and spurs of the ranges, including the Saltoro and the Sasir ranges. The central portion of the Karakoram is a monolithic crest. The Karakoram are one of the highest mountain systems in the world. The average elevation is around 6, 000 m; the highest point in the system, Mt. Chogori [Godwin Austen] (8, 611 m), is second in height only to Chomolungma [Mt. Everest]. Many passes in the Karakoram lie at altitudes of 4, 600–5, 800 m.
The topography is mountainous and alpine with rocky crestsand steep slopes. The southern slope is long and the northern isshort. There is considerable talus; stone-trains are found in theintramontane depressions occupied by the valleys of the Shaiok, Karakash, and other rivers. The cross valleys usually are narrow, deep, and steep-walled gorges.
G. D. BESSARABOV
The territory of the Karakoram Mountains belongs to the region of alpine folding, occupying an intermediate position between the structure of the Pamirs and Himalayas. In tectonic terms, the Karakoram are a major anticlinorium with a northwestern strike. Its axial zone was formed by gneiss, crystalline schist, and marble intruded by granodiorite and granite of alpine age; the northeastern zone was formed by argillaceous and carbonaceous rock of the Upper Paleozoic and Mesozoic periods, broken through by individual granitoid bodies. The southwestern zone was formed by weakly metamorphized igneous-sedimentary formations. The structures of the northeastern zone have been tilted sharply toward the north; those of the southwest, toward the south. The systems of major fracture disturbances are the boundaries of the zones. These tectonic zones of various origins were brought together in a single system as a result of intensive uplifts of the Neocene and Anthropogenic times. In the Karakoram are known ore deposits of beryllium and molybdenum (related to the granites), gold (alluvial placers), sulfur (small postmagmatic deposits), precious stones related to the pegmatites, and mineral springs.
I. V. ARKHIPOV
The climate is predominantly semidesert and sharply continental. The moisture conditions of the southern slope are influenced by the monsoon of the Indian Ocean; the northern slope is characterized by exceptional aridity. At the foot of the slopes, total precipitation is around 100 mm; over 5, 000 m it exceeds 500 mm per year. Precipitation in the mountainous zone (with a summer maximum) always falls in the form of snow. Much of the Karakoram is characterized by below-freezing average annual air temperatures. Other characteristic features of the climate include intensive solar radiation, large daily fluctuations of the air temperature, and significant evaporation.
The glaciated area is 17, 800 sq km. Here lie the largest glaciers of the temperate latitudes, including Siachen, which is 75 km long; Baltoro, 62 km; Rimo, 45 km; and Taldybulak, 30 km. Glaciation has developed more heavily on the southern, wetter slope. The snowline on the southern slope of the Karakoram is around 4, 700 m, and the glaciers descend to 2, 900 m; on the northern slope, the snowline is around 5, 900 m, and the glaciers extend to 3, 500–3, 600 m. Traces of ancient glaciation can be found at 2, 600–2, 900 m and higher.
The Karakoram are the divide of the Indus and Tarim river basins. The thaw waters of the seasonal and perpetual snow and glaciers are the basic source of water for the rivers. Groundwater accumulates in the talus and contributes to a more even drainage during the year. Thick ice bodies form in the winter. The rivers receive little drainage as they flow through the middle and lower slopes of the range. Landlocked lakes and salt swamps are sometimes encountered in the central parts of the intermontane depressions.
The significant contrasts in the wetness of the northern and southern slopes and the fluctuations of altitude within the Karakoram have caused a great diversity of landscapes; this distribution is subordinate to the patterns of altitude zonality. On the northern slopes, up to 2, 400–2, 800 m, there are desert landscapes with a sparse vegetation cover of Russian thistle (Salsola kali), Reaumuria, and Ephedra. Extensive areas are completely devoid of vegetation. Only around the sources of the Raskemdar’ia River and its tributaries (the Tarim basin) does one encounter thickets of brush (chiefly barberry) and poplar. Up to an elevation of 3, 100 m there are desert-steppe landscapes with sparse thickets of winterfat combined with grasses (sheep’s fescue and feathergrass). Up to 3, 500 m mountain steppe predominates, and the wettest areas and those best protected from wind have meadow steppes with Cobresia. Above this are winterfat and wormwood-winterfat alpine deserts combined with solonchak meadows. On the southern slope in the river valleys up to 3, 000–3, 500 m are forests of pine and Deodar cedar, as well as willow and poplar along the watercourses. Mountain steppes with elements of alpine meadows are encountered higher up.
The most characteristic fauna is the wild yak, the Tibetan antelope (Pantholops hodgsoni), and the addax (Addax nasomaculata); in the southern foothills, wild asses are also encountered. Carnivores include the snow leopard. Rodents are numerous (the Chinese striped hamster and others). The characteristic birds are the sand grouse, the Tibetan snowcock, the partridge, the ibis-bill, the snow pigeon, and the red finch (Pyrrhospiza punicea).
Areas along the banks of rivers and lakes are often used as pastures. In places farming has developed along the southern slopes. Up to 4, 000 m, barley, peas, and alfalfa are grown, and on the lower slopes there are grapes and apricots.
REFERENCESPuliarkin, V. A. Kashmir. Moscow, 1956.
Fiziko-geograficheskoe raionirovanie Kitaia.Moscow, 1957.
Sinitsyn, V. M. Tsentral’naia Aziia.Moscow, 1959.
Fizicheskaia geografiia Kitaia. Moscow, 1964.
G. D. BESSARABOV