河北寿王坟铜矿碳-氧同位素地球化学特征及其意义

C & O ISOTOPIC GEOCHEMISTRY OF SHOUWANGFEN COPPER DEPOSIT,HEBEI PROVINCE

系统研究寿王坟矿区矽卡岩型矿石和斑岩型矿石中热液成因碳酸盐矿物的碳氧同位素组成,结合矿区蚀变白云质围岩地层碳氧同位素组成特征,提出:1)尽管矽卡岩矿床产在碳酸盐地层与中酸性侵入体的接触带上,是碳酸盐地层受热液交代作用的产物,但矽卡岩矿石中热液碳酸盐矿物的碳同位素组成却主要反映了深部岩浆(甚或地幔)来源碳的特征,基本可以排除沉积碳酸盐的碳大规模加入的可能性。2)寿王坟矿田对应着一个与高侵位岩浆岩有关的热液成矿系列,其浅部的下渗大气降水加热环流体系和深部上升的岩浆热液体系,均能在不同部位通过系统的碳氧同位素地球化学研究加以揭示。作为矿山开采主体的矽卡岩型矿体和部分斑岩型矿体都是上升岩浆热液(甚或更深的幔源流体)的产物。

C & O isotope compositions of hydrothermal carbonates in skarn ores and porphyry ores of Shouwangfen copper deposit are systematically studied in this paper Combined with C & O isotope compositions of the altered dolomitic wallrocks, the following points are demonstrated Carbon isotope compositions imply that carbon in the skarn ores were derived mainly from related magma or from mantle Although skarn ores are usually considered as product of interaction between carbonate wallrocks and magmatic fluids, the carbon of the sedimentary carbonate wallrocks seems not involved in the hydrothermal carbonates in the skarn ores The Shouwangfen ore district corresponds to a hydrothermal oreforming system that was promoted by highintruding magmatic rocks Systematic C & O isotopic research can help to reveal the upper part (mainly related to heated and circulating meteoric water) and the lower part (principally related to ascending magmatic fluids) of this hydrothermal oreforming system Both skarn ore and porphyry ore, main targets of the mining activity, are formed by magmatic fluids