扬子板块北缘米仓山地区野猪塘金矿地质特征及成矿时代  

Geological Characteristics and Mineralization Age of Yezhutang Gold Deposit in Micangshan Area,the Northern Margin of Yangtze Block,China

作　　者：尼加提·伊里 高阳 黄岗 贾飞 宇峰 刘芯佟 徐骏 YILI Nijiati;GAO Yang;HUANG Gang;JIA Fei;YU Feng;LIU Xin-tong;XU Jun(College of Earth Sciences,Jilin University,Changchun 130061,Jilin,China;Military Civil Integration Geological Survey Center,China Geological Survey,Chengdu 610036,Sichuan,China;Regional Geological Survey Academy of Shaanxi Geology and Mining Group Co.,Ltd.,Xianyang 712000,Shaanxi,China)

机构地区：[1]吉林大学地球科学学院,吉林长春130061 [2]中国地质调查局军民融合地质调查中心,四川成都610036 [3]陕西地矿区研院有限公司,陕西咸阳712000

出　　处：《地球科学与环境学报》2024年第6期746-757,共12页Journal of Earth Sciences and Environment

基　　金：陕西地矿集团有限公司科研专项资金项目(KY202213)。

摘　　要：扬子板块北缘米仓山地区在新元古代早期发生了强烈的板块相互作用及深部岩浆活动,但区域上同时期的成矿作用发育程度尚不清楚。野猪塘金矿是近年来在米仓山地区新发现的中型金矿床,在矿床地质特征详细调查的基础上,对成矿期热液白云母进行了原位Rb-Sr定年,对其成矿时代进行厘定,并探讨其成矿构造背景。野猪塘金矿体主要赋存在中元古界麻窝子组变质沉积岩中,矿体分布受NEE向朱家坝断裂的次级断裂带控制。金矿体呈脉状和透镜状产出,矿体围岩主要为大理岩、石英岩和千枚岩。矿区内可划分出3条金矿化蚀变带,带内硅化、白云母化与金矿化关系最为密切。野猪塘金矿石按矿物共生组合关系可划分为3种类型,分别为黄铁矿矿石、黄铁矿-褐铁矿矿石及褐铁矿矿石。矿石中的金属矿物主要有黄铁矿、褐铁矿和自然金等,脉石矿物主要为石英、白云母和绢云母等。金成矿过程可划分为热液期和表生期两期,其中,热液期可进一步划分为石英-黄铁矿阶段和石英-白云母-硫化物阶段(主成矿阶段)。热液白云母原位Rb-Sr定年获得的等时线年龄为(850±20)Ma,表明金成矿发生在新元古代早期。这一结果与米仓山地区新元古代早期岩浆作用时代相一致,矿床形成于该时期扬子板块北缘的板块俯冲背景。通过金成矿时代和构造背景的对比认为,扬子板块周缘具有较大的与罗迪尼亚超大陆聚合和裂解有关的金成矿潜力。Intense plate interactions and deep magmatic activities occur in Micangshan area,the northern margin of Yangtze Block during Early Neoproterozoic.However,the extent of contemporaneous mineralization in the region remains unclear.Yezhutang gold deposit is a newly discovered medium-sized gold deposit in Micangshan area in recent years.Based on the detailed investigation of deposit geological characteristics,in-situ Rb-Sr dating on hydrothermal muscovite that formed in the mineralization period was carried out to determine its metallogenic age,and its tectonic setting was discussed to provide support for studying the deposit genesis and regional gold exploration.Yezhutang gold ore bodies are mainly hosted in the metamorphic sedimentary rocks of Mesoproterozoic Mawozi Formation,and controlled by secondary fault zones of the NEE-trending Zhujiaba Fault.The gold ore bodies occur in vein and lens-like forms,with marble,quartzite,and phyllite as the main wall rocks.Three gold mineralization alteration zones can be identified in the ore district,with silicification and muscovitization closely related to gold mineralization.The gold ores in Yezhutang deposit can be classified into three types based on mineral assemblages,including pyrite ore,pyrite-limonite ore,and limonite ore.The ore minerals are mainly pyrite,limonite,and native gold,while the gangue minerals are primarily quartz,muscovite,and sericite.The gold mineralization process can be divided into two periods,including the hydrothermal period and the supergene period.The hydrothermal period can be further divided into the quartz-pyrite stage and the quartz-muscovite-sulfide stage(the main mineralization stage).The isochron age of in-situ Rb-Sr dating on hydrothermal muscovite is(850±20)Ma,indicating that the gold mineralization occurs in Early Neoproterozoic.It is consistent with Early Neoproterozoic magmatic activity in Micangshan area,suggesting that the deposit forms in the subduction setting in the northern margin of Yangtze Block during this time.Comparison

关 键 词：金矿 热液脉型 RB-SR定年 变质沉积岩 成矿时代 构造背景 扬子板块 

分 类 号：P612[天文地球—矿床学]