甘肃省鹿儿坝金矿流体包裹体研究:对流体演化和成矿机制的探讨  

Fluid Inclusion Study of the Lu’erba Au Deposit in Gansu Province: Discussion on Fluid Evolution and Metallogenic Mechanism

作　　者：常铭 刘家军[1,2] 杨永春[1,2] 翟德高[1,2] 周淑敏[4] 王建平[1,2] CHANG Ming;LIU Jiajun;YANG Yongchun;ZHAI Degao;ZHOU Shuming;WANG Jianping(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 100083,China;School of Earth Science and Resources,China University of Geosciences,Beijing 100083,China;Mudanjiang Natural Resources Comprehensive Survey Center of China Geological Survey,Mudanjiang,Heilongjiang 157000,China;Department of Geological Engineering,Qinghai University,Xining,Qinghai 810016,China)

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国地质调查局牡丹江自然资源综合调查中心,黑龙江牡丹江157000 [4]青海大学地质工程系,青海西宁810016

出　　处：《现代地质》2021年第6期1576-1586,共11页Geoscience

基　　金：国家自然科学重点基金项目(41730426,41030423);中国地质调查局地质调查工作项目(1212011220924)。

摘　　要：西秦岭地区矿产丰富,金资源储量巨大。国内学者对于该区域的众多金矿床开展了大量成矿流体性质及来源的研究工作,但是并没有形成统一的认识;此外,西秦岭礼(县)—岷(县)成矿带,合作—鹿儿坝—崖湾金、汞、锑多金属成矿亚带的成矿流体研究工作比较薄弱。鹿儿坝金矿床为该成矿带的一个代表性金矿床,其赋存于三叠统浊积岩建造中,属于微细粒浸染型金矿。主成矿阶段热液石英脉及方解石脉中流体包裹体主要为H_(2)O气液两相包裹体,少见纯气相包裹体、纯液相包裹体、CO_(2)-H_(2)O三相包裹体。包裹体均一温度范围为81~247℃,盐度范围为1.23%~10.98%。流体包裹体气相成分以水为主,还有少量的CH_(4)、CO_(2)、H_(2)等。氢、氧同位素实验数据表明,流体中δD_(V-SMOW)值变化范围为-84.4‰~-96.0‰、δ^(18)O值的变化范围为-4.20‰~6.45‰,表明成矿流体来源并非单一,可能为岩浆水与大气降水混合来源。此外,构造体制的转换造成流体沸腾,导致了大规模金等物质沉淀、聚集、成矿。The western Qinling Mountains is rich in mineral resources with huge gold reserves.Chinese scholars have carried out a lot of studies on the properties and sources of ore⁃forming fluids in many Au deposits in the region,but there is no unified view on it.In addition,research on ore⁃forming fluids in the Lixian-Minxian gold belt,Hezuo-Lu'erba-Yawan Au⁃Hg⁃Sb polymetallic ore sub⁃belt in the region is relatively weak.The Lu'erba is a typical Au deposit hosted by Middle Triassic turbidite in the ore belt.Fluid inclusions in the main mineralization stage(calcite⁃quartz veins)are dominated by H_(2)O⁃rich vapor⁃liquid inclusions,with minor pure vapor inclusions,liquid inclusions,and CO_(2)⁃H_(2)O three⁃phase inclusions.Homogenization temperatures of the fluid inclusions range from 81 to 247℃,with salinities varying from 1.23%to 10.98%.Vapor phases are mainly composed of H_(2)O,with minor of CH_(4),CO_(2),and H_(2).TheδD_(V-SMOW)values of the ore⁃forming fluids are from-84.4‰to-96.0‰,andδ^(18)O values are from-4.20‰to 6.45‰,indicative of magmatic⁃meteoric fluid mixing.The structural transition may have led to ore⁃fluid boiling,resulting in extensive gold precipitation.

关 键 词：鹿儿坝金矿 流体包裹体 成矿流体 激光拉曼光谱 氢、氧同位素 

分 类 号：P618.51[天文地球—矿床学]