兰坪盆地白秧坪铜钴银多金属矿床成矿物质来源研究

利用白秧坪矿床的S、Pb、C、O、H同位素组成特征和辉砷钴矿的Co/Ni比值特征,对成矿物质来源进行了分析.认为金属硫化物的硫源可能属含有基性火山岩的盆地基底变质岩来源硫和盆地沉积硫酸盐来源硫的混合硫;铅由赋矿地层下伏沉积岩和盆地基底岩石所提供;成矿流体中的CO2具有两种来源,可能分别由蚀变海相碳酸盐岩和正常海相碳酸盐岩热解形成或者沉积有机质脱羧基作用形成,成矿流体属SO4-Cl-Na-Ca型、大气降水演化而成的盆地热卤水;矿床中钴可能也源自含有基性火山岩的盆地基底变质岩.

ORE -FORMING MATERIAL SOURCES OF THE BAIYANGPING COPPER- COBALTSILVER POLYMETALLIC DEPOSIT IN LANPING BASIN, WESTERN YUNNAN

The ore-forming material sources of the Baiyangping copper-cobalt-silver polymetallic deposit have been studied by the characteristics of isotopic compositions of S, Pb, C, O, and H, and the Co/Ni ratio of cobaltite. The results show that sulfur of metallic sulfides may comes from a mixed sulfur-source consisted by the sulfur-source of metamorphic rock of basin basement with basic volcanic rock and the sulfur-source of basin sulfate; lead of ores is provided by the sedimentary rocks and basement rocks; CO_2 in ore-forming fluids have two sources which derived from thermolysis of altered and normal marine facies carbonate or decarbonxylation of sedimentary organic matters, respectively; ore-forming fluids belong to SO_4- Cl-Na-Ca type basin thermal brine which derived from paleo-meteoric water. Cobalt in the deposit may also derive from metamorphic rock of basin basement with basic volcanic rock.