陕西汉中李洞沟金矿床成矿规律及成矿模式探讨  

Discussion on Metallogenic Regularity and Metallogenic Model of Lidonggou Gold Deposit in Hanzhong,Shaanxi Province

作　　者：王小刚 宇峰 贾飞 刘松柏 邵永勇 WANG Xiaogang;YU Feng;JIA Fei;LIU Songbai;SHAO Yongyong(Regional Geological Survey Academe of Shaanxi Geology and Mining Group Co.,Ltd.,Xianyang 712000,Shaanxi,China;Shaanxi Geological and Mineral Third Team Ltd.,Baoji 721000,Shaanxi,China)

机构地区：[1]陕西地矿区研院有限公司,陕西咸阳712000 [2]陕西地矿第三地质队有限公司,陕西宝鸡721000

出　　处：《黄金科学技术》2024年第6期1002-1015,共14页Gold Science and Technology

基　　金：陕西省地勘基金项目“陕西省南郑县碑坝—南岸山一带铜矿预查”(编号:61201304198)资助。

摘　　要：李洞沟金矿是近年来在陕西汉中碑坝地区基底盖层中发现的首个内生金矿床,已圈出金矿体20余条,矿体长度为70~1400 m,平均厚度为0.31~9.80 m,金品位为0.83×10^(-6)~21.21×10^(-6),已达中型规模。通过开展野外地质调查工作,系统梳理了矿体地质特征,结合矿石镜下鉴定,对李洞沟金矿的矿石类型、矿物组合、成矿期次和成矿阶段进行了细致研究,总结了该矿床的控矿条件和成矿规律。研究结果表明:李洞沟金矿床的矿体主要受NNE向断裂控制,矿石类型以角砾岩型和石英脉型为主,属于构造蚀变岩型+石英脉型金矿床;该金矿经历了赋矿层位形成、早期金矿形成、富集成矿和表生风化剥蚀4个成矿阶段;基于研究结果,提出了新的找矿思路,即浅部在石英绢云母片岩内寻找石英脉型金矿体,中—深部寻找由大理岩层间破碎带控制的角砾岩型和石英脉型金矿体。上述认识能够为矿区探边扩量提供必要的勘查依据,也为区域寻找同类型金矿提供有益参考。The Lidonggou gold deposit represents the first newly identified endogenous gold deposit in recent years within the basement cap rock of the Beiba area in Hanzhong area,Shaanxi Province.Over 20 gold ore bodies have been delineated,with lengths ranging from 70 to 1400 meters,and an average thickness between 0.31 and 9.8 meters.The gold grade varies from 0.83×10^(-6)to 21.21×10^(-6),classifying it as a medium-sized deposit.The gold deposit is predominantly hosted within the marble and sericite quartz schist of the Mawozi Formation,and is controlled by north-northeast trending fault structures.The ore types predominantly consist of breccia and quartz vein,formations,characteristic of a tectonically altered rock and quartz vein-type gold deposit.The principal metallic minerals identified include native gold,pyrite,molybdenite,and chalcopyrite.Mineralization processes are primarily characterized by limonitization,pyrite mineralization,and magnetite mineralization,with sporadic occurrences of malachite and azurite mineralization.Silicification,tourmalinization,and gold mineralization exhibit a close interrelationship.Preliminary analyses suggest that the formation of the Lidonggou gold deposit has undergone four distinct stages:The formation of ore layers encompasses several processes,including early-stage gold formation,ore enrichment and mineralization,as well as supergene weathering and erosion.The mineralization process is categorized into three distinct stages:The post-magmatic hydrothermal mineralization phase occurring during the Jinning epoch,the post-magmatic hydrothermal superimposed transformation mineralization phase during the Chengjiang epoch,and the supergene oxidation phase.The“stage of quartz,native gold,and polymetallic sulfides”constitutes the principal mineralization phase in this region.The mineral assemblage during this stage includes quartz,native gold,pyrite,molybdenite,chalcopyrite,and sphalerite,which collectively signify the primary phase of gold re-enrichment in the area.Drilling verif

关 键 词：成矿规律 成矿模式 李洞沟金矿 汉中地区 陕西省 

分 类 号：P618.51[天文地球—矿床学]