摘要
滇西兰坪盆地是三江成矿带的重要组成部分,金顶铅锌矿是区内重要的超大型矿床。为了查明金顶超大型铅锌矿床的成矿物质来源,对金顶矿区围岩样品进行微量元素地球化学分析。结果显示,稀土总量接近大陆上地壳的平均稀土元素总量值,轻稀土元素相对富集、重稀土元素相对亏损,呈明显的右倾型,具有显著的Eu负异常。微量元素特征显示Cu的平均含量为24.4×10^(-6),未发生明显富集迁移。Pb、Zn平均含量随矿体距离远近变化较大(Pb含量为2.9×10^(-6)~24.7×10^(-6),平均含量为13.1×10^(-6);Zn含量为8.8×10^(-6)~236.0×10^(-6),平均含量为76.6×10^(-6)),与矿体距离呈现出明显的相关性,距离矿体越近,含量越高。稀土元素特征及微量元素相关关系分析表明,矿区围岩古近纪云龙组地层不是提供成矿物质的矿源层。矿区石膏锶、硫同位素地球化学性质显示金顶矿区的石膏为晚三叠世三合洞组蒸发沉积型,且在适当的成矿温度条件下(150~300℃),石膏会发生热化学还原作用(TSR),为金属硫化物矿床提供硫源。
The Lanping basin is an important part of Sanjiang belt,and the Jinding lead-zinc deposit is an important superlarge deposit in this area.In order to find out the source of the metallogenic materials of the Jinding superlarge lead-zinc deposit,the surrounding rock samples of the Jinding mining area were systematically collected for geochemical analysis of trace elements.The results show that the total amount of rare earth elements is close to the average total amount of rare earth elements in the continental upper crust.LREE and HREE have obvious differentiations,LREE is abundant,while HREE is defective,showing obvious right sloping type.Eu is obviously negative anomaly.The characteristics of trace elements show that the average content of Cu is 24.4×10^(-6),no obvious enrichment and migration.The average content of Pb and Zn elements varies greatly with the distance from the ore body(The content of Pb is 2.9×10^(-6)~24.7×10^(-6),with average of 13.1×10^(-6);The content of Zn is 8.8×10^(-6)~236.0×10^(-6),with average of 76.6×10^(-6)).The content of Pb and Zn shows a clear correlation with the distance from the ore body,and the closer the distance from the ore body,the higher the content.The analysis of the characteristics of rare earth elements and the correlation between trace elements show that the surrounding rock in the mining area is not a source bed.The characteristics of strontium and sulfur isotopes of gypsum in the mining area reveal that the gypsum in the Jinding mining area is of evaporative sedimentary type in the late Triassic Sanhedong Formation.Under appropriate metallogenic temperature(150~300℃),the gypsum undergoes thermochemical reduction(TSR),which provides sulfur source for metal sulfide deposits.
作者
朱志军
杨志娟
严锦洁
王何均
ZHU Zhijun;YANG Zhijuan;YAN Jinjie;WANG Hejun(School of Earth Sciences,East China University of Technology,Nanchang 330013,China)
出处
《东华理工大学学报（自然科学版）》
CAS
北大核心
2024年第1期1-12,共12页
Journal of East China University of Technology(Natural Science)
基金
国家自然科学基金项目(42362018,U0933605)。
关键词
兰坪盆地
金顶超大型铅锌矿
围岩
微量元素
Lanping basin
Jinding superlarge lead-zinc deposit
surrounding rocks
trace element
