西藏扎西康多金属矿床成矿过程中的流体性质演化初探  

Preliminary Study on Fluid Evolution in the Ore Forming Process of the Zhaxikang Polymetallic Deposit,Tibet,China

作　　者：李应栩[1] 李光明[1] 董随亮[1] 夏祥标[1] 吴建阳[1] 周清[1] 

机构地区：[1]中国地质调查局成都地质调查中心,成都610081

出　　处：《矿物岩石地球化学通报》2015年第3期571-582,共12页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家重点基础研究发展计划项目(2011CB403105);中国地质调查局地质调查项目(12120114050701;12120113036000)

摘　　要：扎西康铅锌银锑多金属矿床是北喜马拉雅成矿带中重要的铅锌锑多金属矿床,对其成矿过程的研究对其深部资源预测具有重要的指导意义。本文通过野外地质调查结合成矿流体包裹体研究,获得该矿床成矿前硅化、成矿早期铁锰碳酸盐化、中早期毒砂黄铁矿化、中期含铅锌硅化、晚期含锑硅化和成矿后硅化方解石化的流体温度分别为297、280、264、251、215-247和183-237℃,盐度分别为17.80%、8.39%、6.50%、5.98%、2.75%-5.29%和4.28%Na Cleq（wt）。研究表明,成矿流体为顺断裂运移的具有显著岩浆贡献的中高温、中等盐度、较高硫逸度含CO2、CH4和N2的热液与中温低盐度下渗大气降水在断裂中混合的产物。两者的混合改变了流体温度、盐度和硫逸度等进而沉淀金属矿物形成矿体。锑矿化温度低于铅锌矿化温度,下部-247℃锑矿化的发现暗示深部有进一步找矿的空间。The Zhaxikang polymetallic deposit is an important deposit in the Northern Himalayan Metallogenic Belt. Research on its mineralization process is important in guiding prediction of its resources. On the basis of field surveys,fluid inclusion was studied in this paper. The temperatures of the ore-forming fluids at silicification without mineralization stage,Fe,Mn carbonatization stage,silicification with arsenopyrite and pyrite,silicification with Pb-Zn mineralization stage,silicification with Sb mineralization stage and calcite-quartz post mineralization stage are 297,280,264,251,215-247 and183-237℃ respectively,and the salinities are 17. 80%,8. 39%,6. 50%,5. 98%,2. 75% - 5. 29% and 4. 28% Na Cleq（ wt） respectively. These results showed the ore forming fluids are mixtures of mid-salinity mid-temperature and lowsalinity low-temperature fluids. The mid-salinity fluid contained ore forming materials,CO2,CH4 and N2were contributed by magma and the fluid migrated along the NS-NNE fault zone. The low-salinity fluid was penetrated groundwater and circulated along fault zones. When the two types of fluid were mixing in the fault zones,temperature,salinity,activity of S were changed,and veined and lentoid ore bodies were formed in the fault zones. The temperature of Sb mineralization is lower than that of Pb-Zn mineralization,and the temperature of Sb mineralization in the lower position is about 247℃ suggested that the further exploration should be conducted at deeper sites.

关 键 词：扎西康 铅锌锑银多金属矿床 成矿流体 成矿过程 

分 类 号：P618.2[天文地球—矿床学]