摘要
者桑金矿床赋存于上二叠统吴家坪组沉积碎屑岩中,矿体受构造破碎带控制,呈似层状、透镜状产出,是滇东南金成矿带上一个典型的卡林型金矿床。硫铅同位素地球化学研究显示,沉积黄铁矿和热液硫化物(黄铁矿和毒砂)的δ34S值均为正值,变化范围较窄(8.4‰～11.3‰),与二叠纪沉积时期海水硫酸盐δ34S值一致,具有地层硫的特征。矿石中的硫主要通过地层中有机质与海水硫酸盐的热还原作用(TSR)提供。铅同位素组成中,206Pb/204Pb变化范围较宽,207Pb/204Pb和208 Pb/204 Pb较为稳定,计算获得的模式年龄变化范围大(-62～389Ma),甚至出现"负年龄",表明除正常铅外,还有较多的放射性成因铅的混入。铅主要来自于上地壳,有少量岩浆物质的混入。矿石与围岩的硫铅同位素具有一定的继承性,成矿物质主要来自地层。
The Zhesang gold deposit hosted in the Upper Permian sedimentary clastic rocks of the Wujiaping Formation is a typical Carlin-type gold deposit in Southeast Yunnan metallogenic belt. Bed-like and lenticular ore bodies are restricted to fractured zone. The studies of sulfur isotopes indicate that the δ34 S values of hydro- thermal sulfides （pyrite and arsenopyrite） range from 8.3‰ to 11.3‰, which is generally similar to that of di agenetic pyrite and Permian marine sulfates, suggesting the sulfur was mainly derived from strata. Sulfur dynamic fractionation was mainly controlled by organic thermochemical sulfate reduction （TSR）. The research of lead isotope shows that 206Pb/204pb values have a relatively wide variation range, while 207pb/204Pb and 208Pb/204Pb values have little change. The calculated model ages of lead have a great varying range （-62 Ma to 389 Ma）, and even contain negative age, showing that there was an addition of radiogenic lead to common lead. The lead of ore and ore-bearing strata was mainly provided by upper crust, with a little mixed source of magma. In brief, both sulfur and lead isotopic data show an inheritance between ore and ore-bearing strata, that is, ore-forming materials mainly came from strata.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2013年第1期32-39,共8页
Earth Science Frontiers
基金
国家自然科学基金重点项目(40930423)
国家重点基础研究发展计划“973”项目(2009CB421003-01)
长江学者和创新团队发展计划、高等学校学科创新引智计划项目(B07011)
关键词
硫铅同位素
成矿物质来源
者桑金矿床
卡林型金矿床
云南富宁
sulfur and lead isotopes
ore-forming materials
Zhesang gold deposit
Carlin-type gold deposit, Funing County of Yunnan
