“深地资源勘查开采”专项
                燕山期重大地质事件的深部过程与资源效应
The formation of porphyry copper deposits --by Dr. Weidong Sun
2017-03-07 23:17


The distribution of porphyry deposits (Data source USGS)(Sun et al.2015) and the thickness of major arcs (Chiaradia 2014). Overall, thicker arccrust favors porphyry Cu mineralization, but is not the controlling factor. Thewest coast of the South America is the favorite place for porphyry Cu deposit,with a thickness of ~65 km and a total Cu reserve of over 490 million tons.This is followed by the west coast of North America, with a thickness of ~38 kmand a total Cu reserve of ~ 380 million tons. Both are associated with subduction of young oceanic crust that aresubjected to slab melting. Nevertheless, there are many fewer porphyry Cudeposits in the Tibetan Plateau, which is thicker than the Andes. There areessentially no porphyry deposits along the northwestern Pacific margins. Thedistribution of porphyry Cu deposits along the Pacific margins may be plausiblyexplained by ages of subducting oceanic plates (Sun et al. 2013; Sun et al.2012). High oxygen fugacity (DFMQ +2 - +4) and partial melting of subductedyoung oceanic slabs are the two key factors that controls porphyry Cu deposits.Subduction of young oceanic ridges satisfies both criteria and thus is the mostfavorable geologic process for porphyry Cu deposits (Sun et al. 2015). For moredetails please read P.9, 2017(36) Acta Geochimcia



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