新疆西准噶尔宏远钼矿地质特征与成矿流体  

Geological characteristics and mineralization fluid of Hongyuan Mo deposit in the West Junggar,Xinjiang

作　　者：鄢瑜宏 王军年[2] 申萍[1] 潘鸿迪[3] 钟世华[1] 李晶[4] 

机构地区：[1]中国科学院地质与地球物理研究所、矿产资源研究重点实验室,北京100029 [2]新疆地质矿产勘查开发局第七地质大队,乌苏833300 [3]长安大学地质科学与资源学院,西安710054 [4]河北联合大学,唐山063009

出　　处：《岩石学报》2015年第2期491-504,共14页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(U1303293;41390442;41272109);中国科学院重点部署项目(KJZD-EW-TZ-G07);国际科技交流与合作专项(2010DFB23390);国家“305”项目(2011BAB06B01)联合资助

摘　　要：宏远钼矿为新疆西准噶尔地区近年新发现的斑岩型矿床,发育细脉状和浸染状矿化,矿石矿物以辉钼矿为主,其次为黄铜矿、黄铁矿、磁黄铁矿等,热液蚀变发育。本文通过流体包裹体研究,发现宏远钼矿与大多数斑岩钼矿不同,成矿流体含甲烷,属于Na Cl-H2O-CO2-CH4体系,具有还原性。黑云母电子探针研究表明,花岗岩结晶阶段氧逸度较高。成矿流体中甲烷的C同位素值分布于-31.08‰^-26.44‰之间,表明CH4主要是来自地壳有机碳。成矿早阶段流体均一温度集中于340~360℃,此阶段存在中高温-高盐度流体和低盐度流体的不混溶,流体呈弱氧化性,Mo、Cu等金属矿物倾向于向出溶流体中富集,Mo、Cu矿化沉淀较少,发育白云母化围岩蚀变;成矿主阶段均一温度集中于280~300℃,低盐度,在沸腾作用、大气水加入以及还原性增强条件下,Mo、Cu等金属矿物大量沉淀,形成主矿体,伴随绢云母化蚀变;成矿晚阶段均一温度降低为160~180℃,流体演化为低温低盐度流体,成矿作用减弱,围岩蚀变主要为碳酸盐化。The Hongyuan Mo deposit is a newly discovered porphyry-type deposit in the West Junggar region, Xinjiang, which occurs fine vein and disseminated mineralization. Main ore mineral is molybdenite, followed by chalcopyrite and pyrite. It develops hydrothermal alteration. Based on fluid inclusion studies, we find it different from typical porphyry Mo deposit, with the existence of CH4 in ore-forming fluid, belonging to NaC1-H2 O-CO2-CH4 fluid system. Geochemical data of biotite shows a slightly high oxygen fugaeity in the granite crystallization stage. The C isotope data of CH4 in ore-forming fluid is ranging from -31.08%0 to -26.44‰, indicating the source of crustal organic carbon. Stage I , the early stage of mineralization, the homogenization temperature mainly is 340 - 360℃, with high temperature-high salinity and low salinity fluids, weakly reduced fluid, Mo, Cu and other metal minerals are enriched in fluid, with little Mo, Cu mineralization, developing muscovite alteration at high temperature. Stage II, the main stage of mineralization, the homogenization temperature mainly is 280 -300℃, low salinity, the combined action of boiling, atmospheric water and reducing environment causes a large amount of precipitation of Mo, Cu and other metal minerals, forming the main ore body, with sericitization alteration. Stage Ⅲ, the late-mineralization stage, the homogenization temperature mainly is 160-180℃, fluid changes to low temperature and low salinity, with weakened mineralization and earbonatization alteration of wall rock.

关 键 词：流体包裹体 稳定同位素 电子探针 宏远钼矿 西准噶尔 新疆 

分 类 号：P618.65[天文地球—矿床学]