投稿时间：2015-09-15
修订日期：2015-12-15
网络发布日期：2016-08-25
中文摘要:广东大降坪硫（铅锌）矿床位于与岩浆作用有关的大绀山多金属矿田的中部，主矿体为赋存在震旦纪变质岩中的层状、透镜状黄铁矿矿体，最近在两个不同产状的黄铁矿矿体下部又新发现了脉状及层状铅锌矿体。文章通过对铅锌矿体的年龄及硫同位素研究，探讨其与主矿体的成因关系，获得了脉状铅锌矿体中闪锌矿的Rb-Sr等时线年龄为（88.5±3.9）Ma，即晚白垩世，与上部黄铁矿矿体的年龄（约630 Ma）相差较大，而与整个大绀山多金属矿田的成矿作用时限一致。三种不同产状的矿体硫同位素组成差异明显：层状黄铁矿矿体富集硫的轻同位素（δ34S=-10.90‰~-25.55‰），且与围岩的硫同位素范围一致，说明硫来自生物的细菌还原硫；透镜状黄铁矿矿体δ34S组成范围较宽（-9.38‰~22.69‰），具多源性硫的特征；铅锌矿体的δ34S在-7.1‰~6.4‰之间变化，硫可能来自深源岩浆，并受围岩成分混染。多方面的证据表明，大降坪黄铁矿矿体下部的铅锌矿体形成于晚白垩世的岩浆热液成矿作用，透镜状黄铁矿矿体受到岩浆热液的叠加。
Abstract:Dajiangping deposit, Located in the central part of the Daganshan magmatic-related polymetalic orefield,is the largest pyrite deposit in China. The pyrite orebodies occur in the Sinian metamorphic rocks in laminated and lenticular forms. Recently, new veins and layered Pb-Zn orebodies underlying the pyrite orebodies were discovered. The age of sphalerite from the lead-zinc orebody was determined by the Rb-Sr isochron method, which yielded a Rb-Sr isochron age of (88.5±3.9) Ma, completely different from that the pyrite orebody (~630 Ma), but consistent with the metallogenic age of the Daganshan orefield. The sulfur isotope compositions of sulfides from three orebodies were analyzed. The results show that the layered orebody has the δ34S values of (-10.90‰~-25.55‰), suggesting the reduction of the bacteria sulfate. The lenticular orebody has broad δ34S values, ranging from -9.38‰ to 22.69‰, implying that it had complicated sulfur sources, including the mixture of magmatic source. The δ34S values of the lead-zinc orebody are -7.1‰~6.4‰, showing the characteristics of deep source sulfur. These data indicate that the lead-zinc orebody was formed by magmatic hydrothermal mineralization in Cretaceous, and the lenticular pyrite orebody might have been superimposed by it.
keywords:geochemistry sphalerite Rb-Sr isochron age sulfur isotope pyrite orebody lead-zinc orebody Dajiangping S (Pb-Zn) deposit
文章编号：
中图分类号：P597
文献标志码：
基金项目:本文受国家自然科学基金项目（编号：41203036）、国家重点基础研究发展计划"973"课题（编号：2012CB416704）和中央级公益性科研院所基本科研业务专项资金（编号：K1323）共同资助
引用文本：
赵海杰,余长发,韩心巧,郑伟.2016.广东大降坪硫(铅锌)矿床岩浆热液叠加作用——来自闪锌矿Rb-Sr年龄及硫同位素的证据[J].矿床地质,35(4):795~808ZHAO HaiJie,YU ZhangFa,HAN XinQiao,ZHENG Wei.2016.Magmatic hydrothermal superimposition in Dajiangping S (Pb-Zn) deposit, Guangdong Province: Rb-Sr isochron age and sulfur isotope evidence[J].Mineral Deposits35(4):795~808
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