| 陕西旬阳地区小河金矿硫铅同位素组成及地质意义 |
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| 引用本文： | 孟五一,刘家军,魏立勇,张振,吴欢欢,范堡程,潘元,李国英,贾彬.陕西旬阳地区小河金矿硫铅同位素组成及地质意义[J].现代地质,2021,35(6):1587-1596. |
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| 作者姓名： | 孟五一 刘家军 魏立勇 张振 吴欢欢 范堡程 潘元 李国英 贾彬 |
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| 作者单位： | 1.中国地质调查局 西安矿产资源调查中心,陕西 西安 7101002.中国地质大学 地质过程与矿产资源国家重点实验室,北京 1000833.中国地质大学(北京) 地球科学与资源学院,北京 100083 |
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| 基金项目： | 中国地质调查局地质调查项目(DD20208009) |
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| 摘 要： | 小河金矿是近年来在南秦岭中带发现的中型金矿床,矿石类型为微细浸染型,矿床受地层和构造双重控制。在野外工作基础上,根据矿物组合及穿插关系划分了4个成矿阶段:Ⅰ,成矿早期少硫化物石英脉成矿阶段;Ⅱ,石英脉、黄铁矿、毒砂成矿主阶段;Ⅲ,石英脉-多金属硫化物成矿主阶段;Ⅳ,方解石、石英脉成矿晚阶段。其中Ⅱ、Ⅲ阶段是主要金矿化阶段。不同阶段样品的原位硫同位素结果显示:成矿早阶段石英脉期的黄铁矿δ34S值为20.80‰~25.77‰,均值为23.59‰;主成矿期II阶段中黄铁矿、毒砂δ34S值为15.46‰~19.12‰,均值为17.5‰;主成矿期Ⅲ阶段中方铅矿、闪锌矿δ34S值为11.35‰~16.78‰,均值为13.88‰。硫同位素特征指示硫以沉积硫为主,成矿过程可能存在低δ34S值热液的持续加入。金属硫化物Pb同位素测试结果显示206Pb/204Pb为17.882 1~18.367 4,207Pb/204Pb为15.614 0~15.674 1,208Pb/204Pb为38.016 3~38.934 2,指示小河金矿铅主要源于地壳,同时伴随幔源铅的混入。综合矿床地质特征及硫、铅同位素地球化学特征,认为小河金矿成矿过程可能存在流体混合作用。
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| 关 键 词： | 南秦岭 小河金矿 成矿阶段 硫同位素 铅同位素 |
| 收稿时间： | 2021-06-04 |
| 修稿时间： | 2021-11-01 |
Sulfur and Lead Isotope Compositions of the Xiaohe Gold Deposit at Xunyang,Shaanxi Province,and Its Geological Significance |
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| MENG Wuyi,LIU Jiajun,WEI Liyong,ZHANG Zhen,WU Huanhuan,FAN Baocheng,PAN Yuan,LI Guoying,JIA Bin.Sulfur and Lead Isotope Compositions of the Xiaohe Gold Deposit at Xunyang,Shaanxi Province,and Its Geological Significance[J].Geoscience——Journal of Graduate School,China University of Geosciences,2021,35(6):1587-1596. |
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| Authors: | MENG Wuyi LIU Jiajun WEI Liyong ZHANG Zhen WU Huanhuan FAN Baocheng PAN Yuan LI Guoying JIA Bin |
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| Institution: | 1. Xi'an Center of Mineral Resources Survey, China Geological Survey, Xi'an,Shaanxi 710100, China2. State Key Laboratory of Geological Processes and Mineral Resource, China University of Geosciences, Beijing 100083, China3. School of Earth Sciences and Resources,China University of Geosciences, Beijing 100083, China |
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| Abstract: | The Xiaohe is a medium-sized gold deposit discovered in the central belt of the South Qinling Orogen in recent years. The ores are fine-disseminated, and the orebodies are controlled by both strata and structures. Based on field work, four metallogenic stages are divided according to mineral assemblages and crosscutting relationships: Ⅰ. Quartz veins with little sulfide in early-ore-stage; Ⅱ. Quartz veins with main-ore-stage pyrite and arsenopyrite in main mineralization stage; Ⅲ. Quartz veins with main-ore-stage polymetallic sulfides; Ⅳ. Late-ore-stage calcite and quartz veins. Stage Ⅱ and Ⅲ are the main gold mineralization stages. In situ sulfur isotope analysis show that the δ34S value of stage Ⅰ pyrite=20.80‰-25.77‰ (avg.23.59‰), stage Ⅱ pyrite and arsenopyrite=15.46‰-19.12‰ (avg.17.5‰), stage Ⅲ galena and sphalerite=11.35‰-16.78‰ (avg.13.88‰). This indicates that the sulfur is mainly sedimentary-sourced, and there is continuous addition of low-δ34S hydrothermal fluid during the ore-forming process. The sulfide Pb isotope analysis yielded 206Pb/204Pb=17.882,1-18.367,4, 207Pb/204Pb=15.614,0-15.674,1, and 208Pb/204Pb=38.016,3-38.934,2, indicating that the lead was derived mainly from the crust with certain mantle input. Based on the deposit geological and S and Pb isotope characteristics, we suggest that fluid mixing occurred in the Xiaohe gold mineralization. |
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| Keywords: | Xiaohe gold deposit metallogenic stage sulfur isotope lead isotope south Qinling Orogen |
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