江西武山矽卡岩铜矿床的成矿作用

THE GENESIS OF WUSHAN SKARN COPPER DEPOSITS

武山铜矿由矽卡岩型矿床和块状硫化物矿床组成。本文只讨论矽卡岩型矿床。 区内由北向南依次出露志留系——三叠系地层,走向近东西,倾向165°,倾角60°—70°。按岩性。

Genetically the skarn mainly controled by the structure of the contact zone between granodiorite-porohvrv and wall rock and diopiays a ring structure. Mineralization and skarn are basically coincide in spacial distribution. Qutwardly the skarn may be divided into six zones, wits transitional relationship from one to the another.The temperature of mineralization of the skarn deposits is between 200-452℃, of which the copper mineralization is between 310-350℃.The character of the sulfur isotopic composition of the skarn deposits is that the δS34 values are nearly zero.From granodiorite-porphyry to the skarn deposits, the ratios of element pairs in pyrite and the crystalization temperatures of minerals decrease but δS34 values ncrease gradually.The formation of skarn copper deposits is closeiv connected with the granodiorite-porphry. Along contact zone between granodiorite-porphyry and limestone ore solution had carries out diffusive metasomatism and infiltration metasomatism, and a large skarn copper deposits was formed.