川西里伍式铜矿床早石炭世成矿事件——以里伍和中咀矿床为例  

Early Cretaceous metallogeny of the Liwu-type copper deposit, western Sichuan Province: Case study of the Liwu and Zhongzui deposits

作　　者：唐高林 周清[1] 张惠华[1] 李同柱[1] 马国桃[1] 唐学文[2] 代堰锫[1] 沈战武[1] TANG Gao-lin;ZHOU Qing;ZHANG Hui-hua;LI Tong-zhu;MA Guo-tao;TANG Xue-wen;DAI Yan-pei(Chengdu Center,China Geological Survey,Chengdu 610081,China;Sichuan Liwu Copper Mining Company,Ganzi 626200,China)

机构地区：[1]中国地质调查局成都地质调查中心,四川成都610081 [2]四川里伍铜业股份有限公司,四川甘孜州626200

出　　处：《岩石矿物学杂志》2018年第4期637-645,共9页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金青年基金项目(41202067);四川省科技计划项目应用基础研究面上项目(2018JY0175);中国博士后科学基金面上项目(2018M633407);中国地质调查局区域地质矿产调查项目(DD20179506)~~

摘　　要：川西里伍式富铜矿位于扬子地台西缘和松潘-甘孜造山带接合带的江浪穹窿中。矿体大体上呈层状-似层状或透镜状。前期的矿床地质特征调查及矿相学研究结果表明,里伍铜矿的矿体至少经历了两期富集过程:早期硫化物构造变形特征明显,成典型的条带状构造,而晚期的矿化不具变形特征,主要呈块状、团块-浸染状及脉状矿构造叠加改造于前者之上。本文对里伍和中咀矿床中早期条带状黄铜矿进行了Re-Os同位素定年,获得一个良好的等时线年龄为343±11 Ma(n=4,2σ),初始^(187)Os/^(188)Os比值为~2.37。本文据此认为里伍式富铜矿早期成矿事件始于早石炭世,明显晚于赋矿围岩——元古界里伍岩群,该时期的成矿物质主要来源于大陆上地壳。The Liwu-type copper deposits are located in the Jianglang dome, one of the domes in the southeastern Songpan-Ganzi fold belt. Based on field investigations and detailed observations, the authors identified two metallogenic processes： banded sulfide ores occurred at the early stage, and massive, disseminated and veined ores were undeformed and superimposed on the early mineralizations at the late stage. In this paper, the authors present the first chalcopyrite Re-Os geochronological data for the Liwu and Zhongzui deposits to exactly constrain the formation age and origin of the metallogenic event. The result yielded a good isochrone age of 343 ± 11 Ma（ n = 4, 2σ）,with an initial ^（187）Os/^（188）Os ratio of ~ 2. 37. This study indicates that the early banded（ deformed） copper mineralization was initiated in the Early Carboniferous, later than the Meso-proterozoic surrounding rocks of the Liwu Group. The main ore-forming source should have been derived form the upper continental crust.

关 键 词：黄铜矿Re-Os定年 成矿事件 里伍式铜矿 江浪穹窿 松潘-甘孜造山带 

分 类 号：P618.41[天文地球—矿床学] P597.3[天文地球—地质学]