密西西比河谷型(MVT)铅锌矿床：认识与进展  

Some insights and advances in study of Mississippi Valley-type(MVT) lead-zinc deposits

作　　者：刘英超[1] 侯增谦[2] 杨竹森[1] 田世洪[1] 宋玉财[2] 杨志明[2] 王召林[2] 李政[2] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]中国地质科学院地质研究所,北京100037

出　　处：《矿床地质》2008年第2期253-264,共12页Mineral Deposits

基　　金：国家基础研究计划973项目(2002GB41260);“十一五”国家科技支撑计划重大项目课题四(2006BAB01A04);“十一五”国家科技支撑计划重大项目课题八(2006BAB01A08)的资助

摘　　要：MVT铅锌矿床作为一种重要的沉积型铅锌矿床类型一直受到人们的重视,近年来取得了许多重要进展,主要体现在6个方面:①MVT铅锌矿床研究范围逐渐扩大,在全世界发现了诸多相关矿床,多归为其亚类;②提出该类矿床主要分布在造山带的前陆盆地、逆冲推覆带等构造挤压环境,少数产于陆内伸展环境,改变了MVT矿床与板块构造无关的观点;③放射性同位素测年和古地磁测年技术广泛应用,获得了大量成矿年龄数据,表明MVT矿床主要形成在显生宙石炭纪—早三叠纪和白垩纪—第三纪两个时期,与地球演化史上全球尺度的板块会聚时间密切相关;④流体包裹体研究揭示了成矿流体温度主要为90~150℃,盐度w(NaCleq)为10%~30%,成矿流体具有盆地卤水特征,卤水源自近地表蒸发海水或围岩蒸发盐,同位素资料反映Pb来自地壳岩石,S来自地壳岩石或沉积物中残留的硫酸盐。成矿流体驱动机制包括构造挤压和重力驱动两种;⑤古地磁和生物化学标志物判定,单期热液活动可能持续几千到几万年,而整个矿床形成可能持续几个到十几个百万年;⑥矿质沉淀机制主要有3种:流体混合、硫酸盐还原和还原硫机制,不同成矿环境可能受不同机制控制。The Mississippi Valley-type （MVT） Pb-Zn deposits, a significant genetic type of sediments-hosted Pb-Zn deposits, have aroused much interest among geologists. On the basis of researches on such factors of MVT Pb-Zn deposits as their geodynamic settings, geo- logical epochs, fluid-flow syste^a~s, duration of mineralization and precipitation processes, some insights have been obtained and some advances have been made in recent years, which find expression in six aspects： ① Some articles on MVT deposit sub-types were pulished, and these sub-typ. included high-tionperature carbonate replacmnent Pb-Zn deposits, diaper-related deposits, carbonateshosted F-Ba deposits and so on, suggesting that the researches on MVT deposits have become increasingly widespread. ② The idea that plate tectonic movnent had nothing to do with the platform carbonates has been changed. In fact, most of the world＇ s MVT Pb-Zn deposits occur in orogenic forelands, including foreland basins and thrust belts, and a few are located in large-scale extensional environments.③ Remarkable advances in age dating of MVT Pb-Zn deposits provide a new opportunity for understanding the reason and place for the formation of these deposits. The age dating has confirmed the direct connection between the formation of MVT Pb-Zn deposits and the global-scale tectonic events in restricted periods in the geologic history of the earth. The most important period for MVT formation was Devonian-Permian, and the Cretaceous-Tertiary period possessed the second importance, with both of them corresponding to a series of intense tectonic events during the assimilation of some plates. ④The nature of ore fluids is understood more clearly than before. Fluid inclusion determinations show that the temperatures of ore fluids are about 50--250℃ and the salinities are 10--30 wt percent NaCl equiv.. Nevertheless, some detailed reasons remain to be explained in future. Most models for the flow of MVT ore fluids are based on tectonic squeezing or fluid expulsion during

关 键 词：地质学 密西西比河谷型铅锌矿床 构造背景 测年 矿化持续时间 成矿流体 矿质淀积机制 综述 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]