斑岩型铜、金、钼矿床成岩成矿特征差异的原因和意义

文中简要总结了斑岩型金矿、铜矿和钼矿在产出的构造环境，岩石地球化学特征和出溶流体的温度、压力、盐度、蚀变等方面的异同点，重点从元素的地球化学性质、岩浆的源区和过程(熔体和流体演化)3个方面解释了上述差异。Au、Cu和Mo在地球化学性质尤其是亲硫性上的差异决定了元素在不同的大地构造环境下的岩浆作用过程中的分布、迁移和富集特征，最终控制了矿床的分布。岩浆的源区及其温压条件、熔体上升过程中矿物的分离结晶和中上地壳岩浆房内的演化程度控制了成矿岩浆的地球化学特征，进而影响其就位时的压力和温度，从而导致出溶流体在p-T-X上的变化。结合岩浆岩中大离子亲石元素和SiO2的含量，可以评估斑岩型矿床的类型：高的Rb含量是斑岩型钼矿的特征，高的Ba含量是斑岩型钼+铜矿的特征，高的Sr含量是斑岩型铜+金矿的特征。相对于俯冲环境，后俯冲环境下的成矿岩体具有更高的大离子亲石元素含量。矿区中酸性岩石的结构(斑状、似斑状、不等粒和等粒结构)可以用来初步指示成矿的潜力。

The origin and significance of the differences in petrogenesis and mineralization of porphyry gold,copper and molybdenum deposits

In this paper, we compare the similarities and differences among porphyry Au, Cu, and Mo deposits in tectonic setting, whole rock geochemical characteristics due to ore-causative intrusion, and in temperature, pressure and salinity of exsolved fluid and related alteration. To expound these differences, we reviewed metal geochemistry and magma/fluid source and evolution, which explained the collected whole rock geochemical data and p-T-X of exsolved fluid. The differences in geochemical behavior, especially sulfophile affinities of Au, Cu and Mo, control the elements distribution, transport and enrichment in the magmas. And various magmatism in different tectonic settings control the distribution of ore metals. Factors, such as magma source region, fractional crystallization during ascent, and intra-chamber magma evolution in the middle and upper crust, shape the magmas geochemical characteristics which affect the pressure and temperature of emplacement to cause fluid exsolution at various p-T-X. The contents of LILEs (Rb, Sr, Ba) and SiO2 in magmatic rocks can be used to determine mineralization types in general: porphyry Mo deposits prefer high Rb content; Ba is enriched in porphyry Mo-Cu deposits; and Sr content will be the highest in porphyry Cu-Au deposits. Compared to subduction setting, LILE content in ore-causative magmatic rocks should be higher in post-subduction environment, where ore potential can be indicated initially from the textures (porphyry, weakly porphyry, heterogranular, equigranular, etc.) of intermediate to silicic rocks.