湖南瑶岗仙复式花岗岩岩石成因及与钨成矿关系  

Petrogenesis of the Yaogangxian granites and implications for W mineralization Hunan Province

作　　者：董少花[1,2] 毕献武[1] 胡瑞忠[1] 陈佑纬[1] 

机构地区：[1]中国科学院地球化学研究所,矿床地球化学国家重点实验室,贵阳550002 [2]中国科学院大学,北京100049

出　　处：《岩石学报》2014年第9期2749-2765,共17页Acta Petrologica Sinica

基　　金：国家重点基础研究发展计划(973)项目(2007CB411404);国家自然科学基金项目(40373020)联合资助

摘　　要：瑶岗仙复式花岗岩体位于南岭复杂构造带北端,赋存着大型瑶岗仙钨矿床。瑶岗仙花岗岩高硅、富碱,属于高钾钙碱性系列,为分异的S型花岗岩。系统的单颗粒锆石LA-ICP-MS U-Pb同位素年龄测定表明,瑶岗仙复式花岗岩体有多期成岩事件,分别为：170Ma形成的粗粒二云母花岗岩,162Ma形成的中细粒二云母花岗岩,157Ma形成的细粒白云母花岗岩,表明花岗质岩浆经历了多期脉动侵位。元素地球化学及Sr-Nd同位素特征表明,瑶岗仙花岗岩成岩物质来源于古元古代的泥质岩。瑶岗仙花岗岩成岩年龄为170~157Ma,处于燕山期陆内伸展-减薄的构造环境。瑶岗仙花岗岩的成岩事件与钨矿床成矿事件在时空上高度吻合,花岗岩岩浆经历了高度分离结晶并产生富挥发分的流体,表明花岗岩可能为岩浆期后热液阶段成矿作用提供了原始流体和物质来源。The Yaogangxian composite granitic pluton is located in the north of Nanling complex structural belt, hosting the giant Yaogangxian tungsten deposit. The Yaogangxian granites are differentiation S-type granite with the characters of highlyacid, hyperalkaline and peraluminous, belonging to the high-K cale-alkalie series granite. LA-ICP-MS zircon U-Pb dating method was applied to obtain the ages of different types of the Yaogangxian granites. The Yaogangxian composite granitic pluton can be divided into three stages according to their emplacement ages, including coarse-grained two-mica granite forming at 170Ma, medium- to fine-grained two-mica granite forming at 162Ma, and fine-grained muscovite granite forming at 157Ma, indicating that the granitic magma had undergone multi-epoch pulsating emplacement. The element geochemistry and Sr-Nd isopotic characters show that source materials of the Yaogangxian granites might come from pelite in the Paleoproterozoic Era. The Yaogangxian granites formed at 170Ma to 157Ma belonging to the Yanshannian Period, occurring in a continental crustal extension and thinning setting. The diagenetic events of the Yaogangxian granites and the metallogenetic events of tungsten deposits were highly consistent in time and space. The granitic magma had experienced high fractional crystallization and produced volatile-rich fluid. So it was indicated that the granites may provide original fluid and material source to mineralization in post-magmatic hydrothermal stage.

关 键 词：SR-ND同位素 锆石LA-ICP-MS U-PB定年 岩浆演化 瑶岗仙花岗岩 瑶岗仙钨矿床 湖南 

分 类 号：P588.121[天文地球—岩石学] P597.3[天文地球—地质学]