Lake Superior (redirected from Gitchigume)

Superior, Lake 

the largest and deepest of the Great Lakes of North America and the largest freshwater lake in the world. Its northeastern portion is in Canada, and its western and southern parts are in the USA. Located 183 m above sea level. Length, 613 km; greatest width, 256 km. Area, 82,400 sq km (of these 28,700 sq km are in Canada). Area of the basin plus the area of lake, 207,200 sq km; greatest depth of the lake, 393 m; volume, 12,200 cu km (more than one-half the total volume of water in the Great Lakes). The trough of the lake is of tectonic origin, deposited in the crystalline rocks of the Canadian shield. In the Anthropogenic period it was subject to the action of glacial erosion. The northern shores of the lake are high (up to 400 m) and rocky; the southern ones are predominantly low and sandy. The shoreline is sharply broken; important bays are Keweenaw and Whitefish; a large island is Isle Royale. In the region of Lake Superior are concentrated deposits of iron ore and copper (on the Keweenaw Peninsula in the state of Michigan).

The lake has no large tributaries; it discharges into Lake Huron via the rapids of the St. Marys River (112 km long). The water of Lake Superior is clear and cold. (In the central portion of the lake, even in summer, the surface temperature seldom exceeds 4° C.) Fluctuations in the water level are regulated for purposes of navigation, power, and so forth; they occur within limits of 1.1 m (seasonal changes are from 40—60 cm, with a winter minimum and a summer maximum). The central portion of the lake does not freeze as a result of autumn and winter storms; the coastal zone becomes covered with ice each year, usually in the beginning of December, and thaws around April 20.

Lake Superior is an important link in the Great Lakes waterway. Up to 22,000 vessels pass through the canals by way of locks that bypass the rapids of the St. Marys River (near the city of Sault Ste. Marie) during a navigational period of about eight months; freight turnover is approximately 130 million tons. Iron ore, coal, grain, and lumber are transported. The lake is rich in fish; those of commercial importance include whitefish, trout, and sturgeon. Important ports are Duluth, Superior, Ashland, Marquette (USA), Fort William, and Port Arthur (Canada).

REFERENCES

Baulig, H. Severnaia Amerika. Moscow, 1948. (Translated from French.)
Kanada; Geograficreskie raiony. Moscow, 1955. (Translated from English.)

O. A. SPENGLER