粤西大降坪黄铁矿床硫、铅同位素组成初步研究  

PRELIMINARY DISCUSSION ON SULFUR AND LEAD ISOTOPE COMPOSITIONS OF THE DAJIANGPING PYRITE DEPOSIT IN WESTERN GUANGDONG PROVINCE

作　　者：张乾[1] 张宝贵[1] 曹裕波[1] 潘家永[1] 曾天育[1] 郝淑芝 

机构地区：[1]中国科学院地球化学研究所

出　　处：《地质学报》1993年第3期232-243,共12页Acta Geologica Sinica

基　　金：中国科学院矿床地球化学开放研究实验室资助项目

摘　　要：大降坪黄铁矿床是产于云开隆起中段偏北震旦系海相碎屑岩-细碎屑岩中的层状硫化物矿床,矿床成因和海底喷气热水沉积作用有关,局部经受了后期热液的叠加改造。黄铁矿的δ^(34)S值在-25.55‰—+21.07‰之间,与矿石及黄铁矿中的有机碳含量呈反比。从条带状细粒黄铁矿到块状粗粒黄铁矿,亦即从南到北,硫同位素组成从富轻硫变为富重硫。条带状矿石的铅同位素组成与矿体围岩一致,为富放射成因上地壳源铅,块状矿石铅同位素组成较均一,三组铅同位素比值较条带状矿石略低,为原始沉积的矿石铅与热液带来基底混合岩铅的混合铅。The Dajianping pyrite deposit is a stratiform sulfide deposit occurring in the Sinian marine clastic and fine clastic rocks in western Guangdong. A part of orebody Ⅳ was reformed by late hydrothermal solutions. There are two types of ores: one is striped ore and the other is massive one. δ~3_fS values of the former are from -25.55‰ to-9.35‰, and the Pb isotope composition is consistant with those of the country rock. δ^(34)S values of the latter ranye from+12.60‰ to+21.07‰, and the Pb isotope ratios are lower than those of the striped ore. Passing from the striped ore of orebody Ⅲ to the massive one of ore body Ⅳ from south to north, organic carbon contents of ore and pyrite decrease and δ^(34)S values of pyrite increase gradually. Different types of ores have different sources of sulfur and lead. Sulfur of the striped ore was derived from the biolochemical reduction of sea-water sulfate in an open environment and lead is synsedimentary upper crust lead. Sulfur of the massive ore was derived from the biolochemical reduction of sea-water sulfate in relative close environment, and lead probably resulted from mixing of synsedimentary lead with that from the basement migmatite brought by later hydrothermal solutions.

关 键 词：黄铁矿床 硫 同位素 铅 组成 

分 类 号：P618.310.4[天文地球—矿床学]