湖南包金山金矿床围岩蚀变特征及成矿流体来源研究  

Study on the Characteristics of Wall Rock Alteration and the Sources of Ore-forming Fluids in the Baojinshan Gold Deposit,Hunan Province

作　　者：丁海洋 周林[1] 鲁玉龙 王鹏[1,2] 汪飞 Ding Haiyang;Zhou Lin;Lu Yulong;Wang Peng;Wang Fei(Schoal of Earth Sclences and Spatial Information Engineering,Hunan University of Science and Technology,Xiangtan Hunan 411201;Geological Survey Institute of Hunan,Changsha Hunan 410114)

机构地区：[1]湖南科技大学地球科学与空间信息工程学院,湖南湘潭411201 [2]湖南省地质调查所,湖南长沙410114

出　　处：《国土资源导刊》2024年第4期45-55,共11页Land & Resources Herald

基　　金：湖南省地质院科研项目(编号:HNGSTP202302)

摘　　要：湖南包金山金矿床位于湘中白马山—龙山—紫云山金矿带的东段,为赋存于前寒武纪浅变质岩中的金矿床。在野外调查的基础上,利用详细显微镜和扫描电镜BSE观察、能谱分析、全岩微量元素分析和Nd同位素分析等多种测试手段,查明包金山金矿床的围岩蚀变特征,并揭示其成矿流体来源。根据蚀变程度,包金山金矿床围岩蚀变可分为外带、中带和内带,自外带至内带蚀变程度逐渐强烈;围岩蚀变主要类型为绢云母化、硅化、碳酸盐化及少量绿泥石化,其中绢云母化、硅化和碳酸盐化蚀变与金成矿的关系最为密切;包金山金矿围岩(板溪群板岩)Rb、La、Nd等元素相对富集,Nb、Sr元素相对亏损;稀土元素总量∑REE为90.58~109.87 mg/kg,REE配分图显示向右倾斜特征,LREE元素富集,δEu值为0.79~0.87,δCe值为0.86~0.97;?Nd(t)值为-12.23~-11.75。通过综合分析包金山金矿围岩、白钨矿及紫云山花岗岩的微量元素和Nd同位素的组成特征,认为成矿流体来自紫云山岩体的早期岩浆活动,并且在成矿过程中有部分围岩成分的加入,进而丰富了对包金山金矿床成矿作用的认识。The Baojinshan gold deposit in Hunan province is located in the eastern section of the Baimashan-Longshan-Ziyunshan gold belt in central Hunan.It is a gold deposit that occurs in shallow metamorphic rocks of the pre-cambrian period.Based on field investigations,this article uses various testing methods such as detailed microscopy and scanning electron microscopy BSE observation,energy spectrum analysis,whole rock trace element analysis,and Nd isotope analysis to identify the rock alteration characteristics of the Baojinshan gold deposit and reveal its source of ore-forming fluids.According to the degree of alteration,the wall rock alteration of the Baojinshan gold deposit can be divided into outer zone,middle zone,and inner zone,with the degree of alteration gradually increasing from the outer zone to the inner zone;The main types of rock alteration are sericitization,silicification,carbonation,and a small amount of chloritization,among which sericitization,silicification,and carbonation alteration are most closely related to gold mineralization;The wall rock of Baojinshan gold mine(Banxi group slate)is relatively enriched in elements such as Rb,La,Nd,while Nb and Sr elements are relatively deficient;The total amount of rare earth elements(REE)ranges from 90.58 to 109.87 mg/kg,and the REE distribution map shows a rightward sloping feature.LREE elements are enriched,withδEu values ranging from 0.79 to 0.87 andδCe values ranging from 0.86 to 0.97;The Nd(t)value is-12.23~-11.75.By comprehensively analyzing the composition characteristics of trace elements and Nd isotopes in the wall rock,scheelite,and Ziyunshan granite of the Baojinshan gold deposit,it is believed that the ore-forming fluid originated from early magmatic activity in the Ziyunshan rock mass,and some wall rock components were added during the mineralization process,thereby enriching the understanding of the mineralization of the Baojinshan gold deposit.

关 键 词：成矿流体 围岩蚀变 ND同位素 包金山 湖南 

分 类 号：P612[天文地球—矿床学] P614[天文地球—地质学]