投稿时间：2023-09-11
修订日期：2024-06-11
网络发布日期：2024-08-23
中文摘要:黄金洞大型金矿床位于江南造山带湘东北矿集区，矿体主要赋存于沉积黄铁矿发育的新元古代冷家溪群板岩中，含金石英脉为主要的矿化类型。为进一步约束成矿系统中金和硫的来源，揭示赋矿围岩对成矿贡献，深化矿床成因认识，文章以赋矿围岩冷家溪群板岩为研究对象，对其沉积黄铁矿进行了系统的岩相学、电子探针显微结构、激光剥蚀等离子质谱（LA-ICP-MS）原位微量元素和硫同位素分析。研究结果显示，冷家溪群板岩中的沉积黄铁矿主要呈团块状集合体，单个颗粒多为几百~几千微米。微量元素分析结果表明，沉积黄铁矿w(As)变化范围介于796×10-6~10 667×10-6，不可见w(Au)多低于1.0×10-6。沉积黄铁矿的原位δ34S值主要介于-10.7‰~-4.7‰，与矿石中的热液黄铁矿（δ34S=-14.2‰~-0.5‰）具有一定相似性。以上分析结果暗示，沉积黄铁矿提供成矿系统中的金的可能性不大，推测黄金洞金矿床Au主要来自深部过程。成矿流体在与围岩相互作用过程中，沉积成因硫加入成矿系统，为解释热液成因黄铁矿硫同位素组成特征提供关键证据。
中文关键词:沉积黄铁矿 原位和微量元素S同位素 黄金洞 湘东北矿集区 江南造山带
Abstract:The Huangjindong gold large-scale deposit is located in the northeastern Hunan ore cluster, Jiangnan orogenic belt, and the ore bodies mainly occur in the slate of the Neoproterozoic Lengjiaxi Group, and auriferous quartz vein is the main ore type. In order to further restrict the sources of gold and sulfur in the ore-forming system, reveal the role of wallrock to the mineralizing system, and finally make a better understanding of the genesis This paper focuses on the sedimentary pyrite from slate of the Lengjiaxi Group, systematic analyses including petrography, microstructure using electron probe, laser in situ trace elements and sulfur isotope were conducted. The results show that sedimentary pyrite occurs as assemblages and the individuals is mostly of hundreds to thousands of μm in size. LA-ICP-MS trace element analytical results show that w(As) concentrations vary from 796×10-6to 10 667×10-6，and invisible w(Au) is mostly less than 1.0×10-6. In situ S isotope analytical results reveal that δ34S value of sedimentary pyrite mainly ranges from -10.7‰ to -4.7‰, which is similar to the hydrothermal pyrite in the ore (δ34S=-14.2‰ to -0.5‰). All results suggest that the majority of Au is sourced from wallrock, indicating Au is mainly associated with deep processes. During the fluid-rock interaction processes, sedimentary sulfur added to the mineralization system, which gives implications for the interpretation of S isotope composition of hydrothermal pyrite in Huangjindong deposit.
keywords:sedimentary pyrite In-situ trace elements and S isotope Huangjindong northeastern Hunan ore cluster Jiangnan orogenic belt
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基金项目:本文得到国家自然科学基金项目（编号：42272073、42003039）资助
引用文本：
孟亚群,李伟,毛景文,吴圣刚,陈孝刚,阴芳圆.2024.沉积黄铁矿微量元素和硫同位素组成对黄金洞金矿床的成因约束[J].矿床地质,43(4):935~950MENG YaQun,LI Wei,MAO JingWen,WU ShengGang,CHEN XiaoGang,YIN FangYuan.2024.Trace elements and sulfur isotopic composition of sedimentary pyrite on constraining ore genesis of Huangjindong gold deposit[J].Mineral Deposits43(4):935~950
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