Abstract:Porphyy copper deposits, an important type of copper resources in China, are widely distributed in the country: the Yenshanian metallogenic belt along coastal region of eastern China makes up part of the mega-metallogenic belt around the Pacific Ocean; the Hercynian metallogenic belt in northern China extends into the metallogenic belt in central-northern Mongolia and eastern U.S. S. R.; the Himalayas-Alpine metallogenic belt in southwestern China might be correlated in time with porphyry copper deposits in Balkan Pen., western Asia, and some other regions. This fully shows that mineral exploration for porphyry copper deposits are quite promising in China. Mineralization of porphyry copper frequently took place in the geosynclinal area during the late stage of orogenic cycle and at the edge of the volcanic basin in the tectonically stable block. The mineralized intrusives, being essentially hypabyssal bodies at shallow or very shallow depths are generally controlled by anticlinal axis, structural nose or two sets of faults. Mineralization seems to concentrate largely in the forefront of an intrusive body or Where the slope of a body turns from steep to gentle; it also occurs at the apex or on both sides of a stock or a kupola, it might even be found in the upper part of a gently-dipping intrusion, in the concave part of a tongue-shaped body, and in the neck or the overlapping part of a mushroom-shaped body. The structural conditions as a rule had much to do with mineralization, and ore-bearing fluids not only accumulated at the contact zone, but made their may in large quantities into the country rock as well. They could even concentrate in the zone of joints, suggesting that their cooling was later than that of the magma. The quartz-sericitization alteration zone, therefore, is essential for ore occurrence. The ore-bearing fluids had undergone complicated process before they finally got concentrated, and this process was proved by abundant data to have been closely related to the magmatic differentiation at depth; the ore-forming process was invariably associated with mantle-crustal mixed magma; the ore-bearing fluids were often concentrated during the middle or late stage of the repeated magmatic intrusion; the hydrothermal alteration zoning and the geochemical zoning of elements are often observed surrounding the intrusive body; metallogenic elements and mineral assemblages are usually rather simple and ore-grade has no significant variation. Mefasomatism and assimilation were likely much more intense previous to the magmatic intrusion than following the intrusion. A good many isotopic data indicate that sulphur came from a mixture of mantle material and lower part of crustal material. The porphyry copper deposit is analogous to the skarn copper deposit and the volcanic copper deposit in source materials but different from them in ore-forming conditions. Porphyry copper deposits almost unexceptionally occur within the inter-mediate-acid rock suite consisting of diorite formation in island arc and quartz -diorite, granodiorite, monzonite-porphyry and quartz-porphyry formations at the continental margin. These bodies of rock are frequently found lying in a transitional zone between the oceanic crust and the continental crust. The island arcs in western Pacific Ocean and the continental margin, therefore, are areas where one may expect porphyry copper deposits to occur.
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周作侠.1983.我国斑岩铜矿特征及其成矿物质来源[J].矿床地质,2(4):43~51.1983.Characteristics And Source Material Of Porphyry Copper Deposits In China[J].Mineral Deposits2(4):43~51
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