METALLOGENIC PROVINCE

geographic region in which predominantly one kind of ore deposit, or a grouping of ore deposits, occurs in relative abundance. Its cause is unknown, but it is postulated that the magmas (molten rocks) underlying such areas may have been richer in those ore minerals than the magmas elsewhere. Among the examples of metallogenic provinces in North America are the gold province on the Canadian Shield that extends for 2,000 miles (3,200 km) and includes all the major Canadian gold camps; the lead-zinc province of the Mississippi River valley, which is the world's largest producer of those metals; the copper province of the southwestern United States and adjacent parts of Mexico, which at one time produced about one-third of the world's copper; and a large silver-lead province in north-central Mexico, which contains widespread, lead-zinc ores very rich in silver. In South America, the copper province extending northward from Chile into Peru provides a considerable portion of the world's copper. Europe has smaller and less well-defined provinces than North or South America; the German lead provinces, the English tin province, and the Scandinavian nickel province are good examples. Several outstanding provinces occur in Africa: the Witwatersrand and Free State (formerly Orange Free State) gold provinces; the Zambia and Katanga (formerly Shaba) copper provinces. Asia's metallogenic provinces include the Siberian Shield gold province, the platinum province in the Urals, the Georgian manganese province, the Malayan tin province, and the Chinese tungsten province. The mineral deposits of Australia do not occur in distinctive metallogenic provinces for the most part; exceptions include the very large gold provinces of Victoria and New South Wales and the silver-lead-zinc province of Broken Hill, New South Wales.