南岭东段岩前矽卡岩型钨矿成矿流体研究  

Metallogenic Fluid Study of the Yanqian Skarn Type Tungsten Deposit in Eastern Nanling Region

作　　者：刘畅 赵正[1] 陆丽娜[3] 曾载淋[4] 刘翠辉[4] 许虹 LIU Chang;ZHAO Zheng;LU Lina;ZENG Zailin;LIU Cuihui;XU Hong(MLR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resource,Chinese Academy of Geological Sciences,Beijing 100037,China;Department of Earth Sczence and Resources,China Universzty of Geoscience ,Beijing 100083,China;Institute of Disaster Prevention,Beijing 106101,China;Gannan Geological Party ,JBED GMR ,Ganzhou 341000,China)

机构地区：[1]国土资源部成矿作用与资源评价重点实验室,中国地质科学院矿产资源研究所,北京100037 [2]地球科学与资源学院,中国地质大学,北京100083 [3]防灾科技学院,北京101601 [4]江西省地质矿产勘查开发局,赣南地质调查大队,江西赣州341000

出　　处：《地质学报》2018年第12期2485-2507,共23页Acta Geologica Sinica

基　　金：《南岭崇义-会昌矿集区三维综合探测与深部成矿预测项目》(编号2016YFC0600208);《中国地质调查局华南8000m科学钻探选址预研究项目》(编号JYYWF20180502);《全国主要矿集区找矿预测子项目-江西省西眉坳地区找矿预测》(编号DD2016005206)联合资助成果.

摘　　要：南岭东段以石英脉型钨矿集中产出而闻名于世,岩前钨矿是该地区新近发现的中型矽卡岩型钨矿。本文在详细矿床地质和成矿期次研究基础上,对矽卡岩型矿体各成矿阶段的代表性矿物石榴子石、白钨矿、石英、方解石及矽卡岩附近白钨矿-黑钨矿石英脉中石英的流体包裹体进行了系统的岩相学、显微测温、激光拉曼光谱分析和氢氧同位素地球化学研究。岩前钨矿流体包裹体类型主要为富液相两相水溶液I型包裹体和含CO_2三相水溶液Ⅳ型包裹体,石榴子石和石英中I型包裹体中偶见子晶。白钨矿-黑钨矿石英脉中的石英相比矽卡岩型矿体中的石英具有更多的Ⅳ型包裹体。早期矽卡岩阶段的流体参数为温度300～510℃、压力32～108 MPa、平均盐度7.64%、平均密度0.69g/cm3,白钨矿主成矿阶段(晚期矽卡岩阶段)的流体参数为温度230～300℃、压力21～64MPa、平均盐度6.99%、平均密度0.87g/cm3,石英-硫化物-碳酸盐阶段的流体参数为温度100～230℃、压力10～62MPa、平均盐度5.81%、平均密度0.95g/cm3。白钨矿-黑钨矿石英脉的形成温度集中于110～320℃,其上限高于矽卡岩型白钨矿的温度上限,推断石英脉型黑钨矿形成温度更高。岩前钨矿成矿流体在从高温至低温的演化过程中,盐度逐渐降低、密度逐渐增大、压力逐渐降低,整体为低盐度、低密度的流体。氢氧同位素分析表明,成矿流体来源主要为岩浆水,晚期有少量大气水的加入。岩前钨矿成矿机制主要包括流体不混溶作用、流体与围岩相互反应、流体自然冷却、流体混合和压力下降,其中以CO_2逸失为特征的流体不混溶作用为重要的成矿机制。岩相学观察、显微测温、激光拉曼光谱分析证实了矽卡岩型矿体及白钨矿-黑钨矿石英脉中石英的包裹体中都含有CO_2。I型包裹体与Ⅳ型包裹体共存、高盐度包裹体与低盐度包裹体共存及�The Eastern Nanling region is famous for forming quartz- vein type tungsten deposit. The Yanqian tungsten deposit is a newly discovered middle- scale skarn type tungsten deposit in this area. On the basis of detailed deposit geology and metallogenic period study, petrography, microthermometry, Laser Raman spectroscopy analysis and hydrogen- oxygen isotope geochemistry study are carried out systematically for representative minerals of each metallogenic stage in skarn type orebody including garnet, scheelite, quartz and calcite, and quartz in scheelite- wolframite quartz- vein near the skarn. The type of fluid inclusions in the Yanqian tungsten deposit mainly consists of type I fluid inclusion which is two- phase with rich liquid phase type aqueous solution fluid inclusion, type IV fluid inclusion which is three- phase type containing CO2 type aqueous solution fluid inclusion. In addition, a few type I fluid inclusions contain daughter crystal in garnet and quartz. The quartz in scheelite- wolframite quartz- vein contains more type IV fluid inclusion than the quartz in skarn type orebody. In early skarn stage, the temperature is 300-510℃, the pressure is 32-108 MPa, the average fluid salinity is 7.64%, and the average fluid density is 0.69g/cm3. In main metallogenic stage of scheelite (late skarn stage), the temperature is 230-300℃, the pressure is 21-64 MPa, the average fluid salinity is 6.99%, and the average fluid density is 0.87g/cm3. In quartz sulfide carbonate stage, the temperature is 100-230℃, the pressure is 10-62 MPa, the average fluid salinity is 5.81%, and the average fluid density is 0.95g/cm3. The formation temperature of scheelite wolframite quartz- vein concentrates in 110-320℃, whose upper limit is higher than the temperature upper limit of skarn type scheelite, indicating that the quartz- vein type wolframite has a higher formation temperature. For the Yanqian tungsten deposit, during the evolution of the ore- forming fluid from high temperature to low temperature, the salinity gradually

关 键 词：钨矿 矽卡岩 南岭 流体包裹体 成矿机制 

分 类 号：P618.67[天文地球—矿床学]