湖北随州黑龙潭金矿石英Rb-Sr同位素年龄及其地质意义  

Rb-Sr isochron age of the Heilongtan Au-deposit in Suizhou,Hubei Province,and its geological significance

作　　者：彭三国[1,2] 胡俊良[1,2] 刘劲松[1,2] 朱江[1,2] 龚银杰[1,2] PENG Sanguo;HU Junliang;LIU Jinsong;ZHU Jiang;GONG Yinjie(Wuhan Center of Geological Survey, CGS, Wuhan 430205, Hubei, China;Research Center for Petrogenesis and Mineralization of Granitoid Rocks,CGS, Wuhan 430205, Hubei, China)

机构地区：[1]中国地质调查局武汉地质调查中心,湖北武汉430205 [2]中国地质调查局花岗岩成岩成矿地质研究中心,湖北武汉430205

出　　处：《地质通报》2017年第5期867-874,共8页Geological Bulletin of China

基　　金：中国地质调查局项目<武当-桐柏-大别成矿带资源远景调查评价>(编号:1212011220515)

摘　　要：通过矿物流体包裹体Rb-Sr同位素测年,获得鄂北黑龙潭金矿石英Rb-Sr等时线年龄为132.6±2.7Ma,表明该金矿床形成于早白垩世中期。矿石石英中流体包裹体Sr同位素初始比(^(87)Sr/^(86)Sr)i平均值为0.710798,小于陆源硅酸盐的值(0.720),高于地幔Sr的初始值(0.707),暗示成矿物质来源于壳幔混合。结合各类岩矿石Au丰度变化,S、Pb、H、O等同位素组成,以及稀土和微量元素特征、成矿流体等研究,认为该矿床的形成可能与燕山期持续伸展阶段大规模构造-岩浆活动有关,燕山期中酸性岩浆活动为金矿成矿提供了主要矿源和热源。The age of the Heilongtan gold deposit in northern Hubei Province was determined by the Rb-Sr isochron method.Sixsamples of quartz-hosted fluid inclusions yielded a Rb-Sr isochron age of132.6±2.7Ma,suggesting that the Heilongtan gold depositwas formed in the Late Cretaceous.The(87Sr/86Sr)i initial ratio of the isochron is0.710798,which is lower than that of the terrige?nous silicates(0.720)but higher than that of the mantle(0.707),implying that ore-forming materials were derived from a mixture ofcrust and mantle components.Combined with the reported S and Pb isotopes,the authors hold that the ore-forming process of theHeilongtan gold deposit was probably related to the Late Mesozoic magmatism in an extensional setting.The magmatism might haveprovided sufficient heat energy,fluid,sulfur and gold for the mineralization of the Heilongtan gold deposit.

关 键 词：石英 RB-SR 定年 成矿时代 黑龙潭金矿 地球化学 

分 类 号：P597.3[天文地球—地球化学] P618.51[天文地球—地质学]