Porphyry type deposits associated with adakite magmas: Case study of porphyry Cu-Au and Cu-Mo deposits in mongolia

摘要

Major porphyry type deposits are spatially and temporally associated with adakitic magmas. Such magmas show high Sr/Y, high Al2O3, and high La/Yb geochemical signature. Case study of late Devonian Oyu Tolgoi and Carboniferous Shuteen deposits show that porphyry Cu-Au are associated with oxidized, high Sr/Y mafic-inermediate adakitic magma. Magma associated with Erdenet and Bayan Uul porphyry Cu-Mo deposits has shown high Sr/Y signature through a combination of fractionation, crustal melting and assimilation. Long-lived magmatic-hydrothermal system is potential for large porphyry deposits.