南秦岭银洞沟银金矿床矿相学与成矿时代  

Mineragraphy and ^(40)Ar/^(39)Ar Geochronology of Yindonggou Ag-Au Deposit, South Qinling Mountains, China

作　　者：朱峰[1] 李文博[1] 胡传胜[1] ZHU Feng LI Wen-bo HU Chuan-sheng(Key Laboratory of Orogenic Belt and Crustal Evolution, Peking University, Beijing 100871, China)

机构地区：[1]北京大学造山带与地壳演化教育部重点实验室,北京100871

出　　处：《矿物学报》2017年第4期386-394,共9页Acta Mineralogica Sinica

基　　金：国家自然科学基金项目(批准号:41373043);全国危机矿山接替资源找矿项目(编号:20089934)

摘　　要：湖北银洞沟银金矿床是南秦岭重要的大型银矿床,矿体产于武当群变质火山岩中,受剪切构造控制,矿石类型主要为石英脉型。矿相学研究表明,含银矿物与方铅矿常同脉产出,从早到晚产出的含银矿物分别为银金矿、自然银、辉银矿、辉铜银矿,有从银矿化向铜矿化转变的趋势,反映了成矿流体从早到晚由氧化变为还原。测得与银金矿密切共生的白云母氩-氩坪年龄为231.0±2.0 Ma(MSWD=0.96),反等时线年龄为229.5±1.4 Ma(MSWD=0.73),与前人测得的本区剪切带多硅白云母氩-氩年龄一致,表明成矿作用与区域剪切构造变形有关。Yindonggou Ag-Au deposit is an important large-size silver deposit in South Qinling mountains, central China. Quartz vein type ore bodies are hosted by the metamorphosed volcanic rocks of Wudang Group and controlled by shear zones. According to field observation and laboratory studies, silver-bearing assemblages are electrum, native silver, argentite and jalpaite in sequence, with a trend from silver mineralization to a copper one, indicating a transition from oxidization to reduction of ore-forming fluid environment. The 40Ar/39Ar plateau age of muscovite intergrowth with Ag-Au minerals is 231.0 ± 2.0 Ma （MSWD = 0.96）, and inverse isochron age is 229.5 ± 1.4 Ma （MSWD = 0.73）. These ages are consistent with the 40mr/39Ar ages of phengite in the shear zones of the mining area, implying that the metallogenesisis related to the regional shear deformation. Keywords： Yindonggou; Ag-Au deposit; geological characteristics; geochronology

关 键 词：银洞沟 银金矿床 地质特征 年代学 

分 类 号：P579[天文地球—矿物学] P597[天文地球—地质学]