Classification, Distribution and Uses of Ores and Ore Deposits - Metals and Society: An Introduction to Economic Geology - page 31

Fig. 2.1 Global distribution of ore deposits. (a) Copper deposits. (b) Lead-zinc deposits.
(c) Ni and Cr deposits. (d) Gold deposits. (e) Uranium deposits from http://gdr.nrcan.gc.ca/
minres/index_e.php
(also spelled Phalabora) intrusion, a carbonatite emplaced in the Archean Kaapvaal
craton of South Africa.
In many magmatic deposits, copper occurs together with nickel (Fig. 2.1c ). This
is the case for most major deposits of this type, not only Sudbury but also Norilsk in
Russia and Jinchuan in China. Another class of nickel deposit is hosted by
komatiite, a type of ultramafic lava that erupted only in the Archean and early
Proterozoic. Komatite-hosted Ni-Cu deposits are therefore restricted to the oldest
parts of the earth's crust, in the greenstone belts of Australia, Canada and
Zimbabwe. But not all nickel deposits are magmatic; another major type is nickel
laterite and for these the distribution is quite different. Whereas crustal structure
and tectonic setting influence the location of the magmatic variety, laterite is a type
of soil that develops at the surface of the crust in hot, humid climates. All deposits
of this type are located in regions that are relatively close to the equator, or were
close to the equator when the deposits formed. The major lateritic Ni deposits are in
New Caledonia, Indonesia, Cuba, Brazil and Australia.
Gold deposits form in a wide range of tectonic settings. The majority of those
shown in Fig. 2.1 d are classed as orogenic gold deposits, which means that they
occur in active margins of the continents, as, for example, the Cordillera of North
America or the Alpine-Himalaya belt. Other examples occur in modern island arc
settings and in the western Pacific or in their Precambrian equivalent, the Archean
greenstone belts of Canada and Australia. Quite a different form of gold deposit is