东昆仑东段哈陇休玛斑岩型钼矿成矿流体特征及成矿机制探讨  

CHARACTERISTICS OF ORE-FORMING FLUID AND METALLOGENIC MECHANISM OF HALONGXIUMA PORPHYRY MOLYBDENUM DEPOSIT IN THE EASTERN PART OF EAST KUNLUN

作　　者：何书跃 李玉龙[2] 陈静[2] 许庆林[3] 王亚栋[2] 白宗海[2] 舒树兰[2] HE Shuyue LI Yulong CHEN Jing XU Qinglin WANG Yadong BAI Zonghai SHU Shulan(The Third Institute of Geology and Mineral Resources Prospecting in Qinghai Province ,Xining 810029,China Qinghai Geological Survey Institute,Northern Qinghai-Tibet Plateau Geological Processes and Mineral Resources Laboratory,Xining 810012,China Shandong University of Science and Technology,Qingdao 266590,China)

机构地区：[1]青海省第三地质矿产勘查院,青海西宁810029 [2]青海省地质调查院青藏高原北部地质过程与矿产资源重点实验室,青海西宁810012 [3]山东科技大学,山东青岛266590

出　　处：《矿物岩石》2017年第3期22-30,共9页Mineralogy and Petrology

基　　金：青海省应用基础研究(2016-ZJ-719);青海省科技厅重大科技专项(2016-SF-A3)

摘　　要：哈陇休玛钼矿位于东昆仑造山带东段,是近年来新发现的斑岩型钼矿床,规模已达中型。与成矿有关的岩体是晚三叠世花岗闪长斑岩流体包裹体的研究表明,石英-辉钼矿阶段流体包裹体类型主要有气液两相和含CO_2三相包裹体两种类型,前者盐水溶液盐度集中在6NaCI.eqv^12 NaCI.eqv间,后者盐度较大主要集中在16%NaCI.eqv^20%NaCI.eqv,该阶段包裹体均一温度集中于260℃~360℃;石英-多金属硫化物阶段流体包裹体主要以气液两相为主,包裹体均一温度集中于200℃~260℃,盐度集中在6%NaCI.eqv^10%NaCI.eqv。成矿流体由中高温、中-低盐度、富CO_2的流体向中低温、低盐度、低CO_2流体演化。沸腾流体包裹体组合的存在暗示了成矿流体的沸腾作用,可能由于压力急剧降低而形成。通过等容线相交法获得沸腾包裹体组合捕获时的压力为84MPa^120 MPa之间,成矿深度估算为3.2km^4.5km。总体上,成矿流体由中高温、中-低盐度、富CO_2的流体向中低温、低盐度、低CO_2流体演化。该矿床形成于东昆仑造山带印支晚期后碰撞环境,成矿花岗闪长斑岩体主要源自下地壳的部分熔融,金属Mo主要来源于下地壳底部,部分萃取于上部地壳,成矿流体中含CO_2组分是大陆环境含Mo岩浆系统的普遍特征。Halongxiuma Mo deposit in the eastern section of East Kunlun Orogenic Belt is a me- dium-sized porphyry molybdenum deposit and the late Triassic granodiorite porphyry has close re- lation with mineralization. Studies of the quartz-molybdenite indicate that there are two types of fluid inclusion,gas-liquid two-phase type and COz-containing three-phase type. The salinity of the former type is in the range of 6-12 NaC1. Eqv and the latter type is 16%-20% NaCl. eqv with the homogenization temperature focused on the 260 ℃-360℃. The fluid inclusions in the quartz- polymetallic sulfide are mainly composed of two phase of gas and liquid and the homogenization temperature ranges from 200 ℃ to 260 ℃ ,salinity ranges from in 6% to 10% NaCl. eqv. The ore- forming fluid is evolved from medium-high-temperature, medium-low-salinity, COz-rich to medi- um-low-temperature,low-salinity and low COz. Boiling fluid inclusion assemblage is formed by the sharply pressure reduction and captured when the pressure is between 84 MPa-120 MPa through isometric line intersection method with depth of 3.2 km to 4.5 km. It is considered that the deposit was formed in the post-collision environment during the Late Indosinian period, and the metallogenetic-related granodiorite porphyry was mainly derived from the partial melting of lower crust. Metal Mo mainly comes from the bottom of the lower crust, while part of it from the extraction in the upper crust. Ore-forming fluid containing CO2 component is the common charac- teristics of the Mo magmatic system in the continental environment.

关 键 词：东昆仑东段 哈陇休玛矿床 流体包裹体 激光拉曼 成矿机制 

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