宁芜南段和睦山铁矿床矿物学特征及其成因意义  

Mineralogy of Hemushan iron deposit in southern part of Ningwu ore concentration area and its genetic significance

作　　者：江勇卫 张智宇[2] 杜杨松[1] 罗淦[1] 张彦文[1] 郑泽军[1] 任春雷[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国地质科学院地质研究所,北京100037

出　　处：《矿床地质》2015年第1期163-178,共16页Mineral Deposits

基　　金：国家青年自然科学基金项目(编号:41302062);中央高校基本科研业务费专项资金项目(编号:2011YYL125);中国地质调查局项目(编号:12120113069900)联合资助

摘　　要：位于宁芜矿集区南部钟姑矿田内的和睦山铁矿床是长江中下游成矿带内的一个典型的中型玢岩铁矿床,其主矿体呈似层状或透镜状产于闪长(玢)岩体与中-上三叠统地层接触带及其附近的灰岩中。近矿围岩蚀变矿化强烈,并具有显著的分带特征。岩(矿)相学研究表明,该矿床的形成经历了成矿前期(钠长石阶段)、主成矿期(阳起石-磷灰石-Ⅰ型磁铁矿阶段、浅闪石-金云母-Ⅱ型磁铁矿阶段和赤铁矿阶段)和成矿后期(石英-黄铁矿阶段和碳酸盐阶段)。矿物学研究表明,热液浅闪石较早阶段阳起石更富Al和Na、而贫Si;晚阶段Ⅱ型磁铁矿较早阶段Ⅰ型磁铁矿更富Ti和Al、而贫Mg。由岩体到矿体方向,金云母中Mg O含量逐渐富集,而Fe O和Ti O2含量逐渐降低,说明浅闪石-金云母-Ⅱ型磁铁矿阶段的成矿温度高于阳起石-磷灰石-Ⅰ型磁铁矿阶段,且阳起石-磷灰石-Ⅰ型磁铁矿阶段成矿热液在演化过程中,温度是逐渐降低的。综合研究表明,和睦山铁矿床为中-高温气液交代充填成因,Ⅰ型磁铁矿的形成以热液交代作用为主,Ⅱ型磁铁矿的生成则以热液充填作用为主,钠化对铁的活化和迁移起了重要作用。The Hemushan iron deposit, which is located in the Zhonggu orefield within the southern part of the NanjingWuhu large ore concentration area, is a typical medium-sized porphyrite iron deposit in the Yangtze River metallogenic belt. The major orebodies occur as layers and lens in the contact zones between dioritic pluton and volcanic rocks and limestone near the contact zones. Alteration and mineralization are intense in the country rock close to the orebody, and exhibit significant zoning： Albitophyre → actinolite-apatite-Ⅰ type magnetite ore →（ tourmaline）-edenite-phlogopite altered rock→edenite-phlogopite-Ⅱ type magnetite ore→marbleized limestone with magnetite→albitophyre. Petrographic and mineragraphic observations support division of the ore-forming process of the deposit into pre-metallogenic, major metallogenic, and post-metallogenic periods. The pre-metallogenic period consists of albite stage, the major metallogenic period comprises actinolite-apatite-Ⅰ type magnetite, edenite-phlogopite-Ⅱtype magnetite, and hematite stages, and post-metallogenic period is composed of quartz-pyrite and carbonate stages. Mineralogical studies indicate that, in comparison with actinolite of the early stage, hydrothermal edenite contains more Al, Na, and less Si, whereas late stage Ⅱ type magnetite contains more Ti, Al, and less Mg than the magnetite of stage Ⅰ type. From rock mass to orebodies, Mg O is gradually concentrated in phlogopite while Fe O and Ti O2 tend to decrease. It is shown that the metallogenic temperature of edenite-phlogopite-Ⅱ type magnetite stage is higher than that of actinolite-apatite-Ⅰ type magnetite stage. And, the temperature of ore-forming fluids in actinolite-apatite-Ⅰ type magnetite stage is gradually reduced. Integrated studies indicate that the Hemushan iron deposit is a medium-high temperature gas-liquid metasomatic-filling deposit. Hydrothermal metasomatism formed Ⅰtype magnetite, and hydrothermal filling produced Ⅱ type magnetite. Ⅰ n the process of

关 键 词：地球化学 矿物学 阳起石-磷灰石-磁铁矿矿石 浅闪石-金云母-磁铁矿矿石 成矿过程 宁芜和睦山铁矿床 

分 类 号：P618.31[天文地球—矿床学]