Metallogenic Province

metallogenic province, geographic area characterized by a particular assemblage of mineral deposits, or by a distinctive style of mineralization. The causes of formation of metallogenic provinces are not clear. Some provinces were formed as a result of plate tectonic activity in which magmas (molten rocks) formed adjacent to a plate edge are richer in certain ore minerals than magmas elsewhere. The great belt of porphyry copper deposits that extends north from central Chile into Peru is a metallogenic province associated with the subduction of the Pacific Ocean floor beneath the South American plate.

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins. The expelled waters are enriched in lead and zinc and under suitable circumstances can deposit their dissolved loads to form ore deposits. The great lead-zinc province of the Mississippi Valley drainage basin is an example of a province formed by expulsion of metal-bearing pore waters.

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 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. 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 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. In Australia there is a large gold province in Victoria and New South Wales and a rich lead-zinc-copper province in western Queensland and the Northern Territory known as the Mt. Isa inlier.