云南金顶铅锌矿床硫同位素地球化学特征及其成矿学意义
发布时间：2018-09-03 13:37
【摘要】：位于云南西北部的金顶铅锌矿床不仅是世界上形成时代最新,而且是唯一的陆相碎屑沉积岩容矿的超大型铅锌矿床,是中国目前最大的铅锌矿床,也是世界上铅锌总储量大于1000×104t的17个超大型铅锌矿床之一。金顶铅锌矿床成矿过程中大约需要317×104m3的H2S。金顶铅锌矿床有别于世界沉积岩容矿铅锌矿床的其他类型,如MVT型矿床、SEDEX型矿床和SST型矿床。对于这样一个矿床,由于其储量巨大,因此对其成矿作用过程中还原性硫的来源,形成机制的研究就显得尤为重要。之前,很多学者认为金顶铅锌矿床还原性的硫主要通过细菌硫酸盐还原作用(BSR)和高温热化学还原作用(TSR)形成,大部分的硫源自三叠纪地层膏岩被还原所产生的硫化氢,矿区的膏岩主要来源于三叠纪海相地层,天青石的SO42-主要来源于石膏的溶解。笔者认为(1)金顶铅锌矿床具备了细菌硫酸盐还原作用(BSR)发生的条件。(2)金顶铅锌矿床硫化物硫同位素δ34S分布于-32‰~0‰,并具有两个峰值,主要分为两组:第一组δ34SVCDT集中在-8‰~0‰区间,第二组δ34SCDT集中在-32‰~-10‰区间。其中大部分主要集中在-32‰~-10‰区间,具有较低的δ34S值。认为金顶铅锌矿床还原性硫通过细菌硫酸盐还原作用(BSR)和硫酸盐高温热化学还原作用(TSR)而形成。(3)金顶矿区不同位置不同矿段和不同成矿阶段形成的硫化物矿石具有不同的硫同位素δ34S值,总体而言,矿区西部和第一成矿阶段(主成矿阶段)形成的硫化物矿物具较低的硫同位素δ34S值,其还原性硫可能主要来源于细菌硫酸盐还原作用;而矿区东部和第二成矿阶段形成的硫化物矿物具较高的硫同位素δ34S值,既显示了BSR的特征,同时也具备TSR的特征。(4)金顶铅锌矿床这种不同位置,不同成矿阶段硫化物具有不同硫同位素δ34S值的特征,表明金顶矿区还原性的硫应该是在金顶穹窿中由硫酸盐原地还原而形成,并非其他地方搬运而来。(5)金顶矿区有机质硫同位素δ34S值分布较分散,从-26‰到-4‰均有分布,且均为负值。认为金顶铅锌矿床中还原性硫可能除了来源于BSR作用和TSR作用之外,也可能来源于含硫有机质的热裂解作用(TDS)。有机质在成矿作用过程主要起到了提供还原性硫源以及催化BSR作用发生的作用。
[Abstract]:The Jinding Pb-Zn deposit, located in the northwest of Yunnan, is not only the latest age of formation in the world, but also the only superlarge Pb-Zn deposit in continental clastic sedimentary rocks. It is the largest Pb-Zn deposit in China at present. It is also one of the 17 super-large lead-zinc deposits with total reserves of 1000 脳 10 ~ 4t in the world. About 317 脳 104m3 H _ 2s are needed in the metallogenic process of the Jinding lead-zinc deposit. The Jinding lead-zinc deposit is different from other types of sedimentary rock bearing lead-zinc deposit in the world, such as MVT type deposit and SST type deposit. For such a deposit, because of its huge reserves, it is particularly important to study the source and formation mechanism of reducing sulfur in the process of mineralization. Previously, many scholars believed that the reducing sulfur of the Jinding Pb-Zn deposit was mainly formed by bacterial sulfate reduction (BSR) and high temperature thermochemical reduction (TSR). Most of the sulfur was derived from hydrogen sulfide produced by the reduction of the gypsum rocks in the Triassic strata. The gypsum is mainly derived from the Triassic marine strata, and the SO42- of the celadite is mainly derived from the dissolution of gypsum. The authors believe that (1) the Jinding Pb-Zn deposit has the conditions for the occurrence of bacterial sulfate reduction (BSR). (2) the sulfur isotope 未 34S of the Jinding Pb-Zn deposit is distributed in -32 鈥，
本文编号：2220126
[Abstract]:The Jinding Pb-Zn deposit, located in the northwest of Yunnan, is not only the latest age of formation in the world, but also the only superlarge Pb-Zn deposit in continental clastic sedimentary rocks. It is the largest Pb-Zn deposit in China at present. It is also one of the 17 super-large lead-zinc deposits with total reserves of 1000 脳 10 ~ 4t in the world. About 317 脳 104m3 H _ 2s are needed in the metallogenic process of the Jinding lead-zinc deposit. The Jinding lead-zinc deposit is different from other types of sedimentary rock bearing lead-zinc deposit in the world, such as MVT type deposit and SST type deposit. For such a deposit, because of its huge reserves, it is particularly important to study the source and formation mechanism of reducing sulfur in the process of mineralization. Previously, many scholars believed that the reducing sulfur of the Jinding Pb-Zn deposit was mainly formed by bacterial sulfate reduction (BSR) and high temperature thermochemical reduction (TSR). Most of the sulfur was derived from hydrogen sulfide produced by the reduction of the gypsum rocks in the Triassic strata. The gypsum is mainly derived from the Triassic marine strata, and the SO42- of the celadite is mainly derived from the dissolution of gypsum. The authors believe that (1) the Jinding Pb-Zn deposit has the conditions for the occurrence of bacterial sulfate reduction (BSR). (2) the sulfur isotope 未 34S of the Jinding Pb-Zn deposit is distributed in -32 鈥，
本文编号：2220126
本文链接：https://www.wllwen.com/kejilunwen/kuangye/2220126.html
