摘要
Major models for porphyry copper deposits hold that there is always a shallow fertile magma chamber below the ore deposits, which provides ore-forming fluid for the formation of the ore deposits. A lot of recent researches aboard have revealed the characteristics of the chamber: it lies at the depth of about 5 km below the surface, its volume directly controls the size of the ultimate deposit, its shape is flatlying,it is relatively closed, and its life span is comparatively short (generally about 2 Ma). The favorable conditions for the formation of the shallow fertile magma chamber in island arc or continental arc are the middle compression stress field or the stress relaxing period after compression. The Cu-rich magma originates from the deep MASH zone (often mixed with mafic melt), always generated at the end of a long evolved tectono-magmatism cycle.
