冈底斯斑岩铜矿成矿模式

已有的斑岩铜矿成矿模式都是建立在“B”型俯冲基础上的，而冈底斯斑岩铜矿成矿为18～12Ma，主碰撞期为65Ma，因此属于“A”型俯冲时期，即印度大陆壳俯冲到亚洲大陆壳之下的早期，此时夹于两者之间的新特提斯洋壳尚未消失掉，由此上地幔脱水和部分熔融提供了斑岩铜矿的主要成矿的物质来源。本文讨论了俯冲作用与斑岩铜矿的关系，通过驱龙和冲江两个代表性矿床的Nd、Sr同位素讨论了冈底斯斑岩铜矿成矿物质来源，通过矿带结构和成矿年代等制定了冈底斯斑岩铜矿成矿模式。

A Genetic Model for the Gandise Porphyry Copper Deposits

Existing genetic models for porphyry copper deposits are based on B-type subduction. The Indian plate came into collision with the Asian plate 65 Ma ago. Ore-formation for the Gangdise porphyry copper deposits took place during 18 Ma to 12 Ma when early subduction of the Indian continental crust beneath the Asian continental crust occurred. Such a subduction belongs to A-type subduction. Then, Tethyan oceanic crust between the Indian continental crust and the Asian continental crust still existed. Thus, dehydration and partial melting of the upper mantle provided ore matter for the Gangdis6 porphyry copper deposits. This paper deals with relationship between plate subduction and ore-formation of porphyry copper deposits and ore matter sources for the Gangdise porphyry copper deposits based on Nd. Sr isotope compositions for the Qulong and Chongjiang porphyry copper deposits. A genetic model for the Gangdise porphyry copper deposits is advanced on the basis of ore zone structure and ore-forming ages.