黑龙江高岗山斑岩型钼矿床地球化学特征及成因探讨

发布时间：2018-03-13 13:48

  本文选题：成矿流体　切入点：岩石地球化学　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：小兴安岭-张广才岭成矿带是我国重要的钼成矿带之一,主要成矿类型为斑岩型和矽卡岩型,其成矿主要与燕山早期太平洋板块俯冲作用有关。高岗山斑岩型钼矿床是小兴安岭-张广才岭成矿带上首次发现的早三叠世成矿的斑岩型钼矿床,研究程度很低。本文在野外调查的基础上,对高岗山钼矿床进行了一定室内研究,主要包括光薄片鉴定、岩矿石地球化学分析、成矿流体包裹体测试,并进一步探讨了该矿床的成因。高岗山钼矿赋矿岩体为晚二叠世花岗岩小岩株,受岩浆岩、地层、构造和围岩蚀变的复合控制,显示典型斑岩型钼矿床特点。区内主要侵入岩为花岗斑岩、似斑状花岗岩、花岗闪长岩,成矿岩体属于过铝质、橄榄粗玄岩系列的S型花岗岩。区内斑状花岗岩为成矿提供了有利的围岩条件。硅化、钾化等围岩蚀变控制了矿石类型,空间展布以及矿化强度。矿床结构主要有斑状结构、似斑状结构、环带结构等,矿石构造主要为片麻状构造、脉状构造、浸染状构造、细脉浸染状构造、星点状构造和角砾状构造等。高岗山钼矿床床与典型斑岩型钼矿床成矿阶段相似,分为4期,分别为:(Ⅰ)石英-钾长石阶段;(Ⅱ)石英-黄铁矿-磁黄铁矿±辉钼矿阶段;(Ⅲ)石英-黄铁矿-辉钼矿阶段;(Ⅳ)石英-方解石±萤石阶段。成矿岩体岩石地球化学特征显示其形成环境为大陆碰撞环境。成矿地球动力学背景可能与 佳蒙地块‖与华北地块北段东缘的碰撞拼合作用有关。对各成矿阶段的矿物中的流体包裹体进行测试,测试结果显示高岗山钼矿床的成矿流体具有中-高温、中-低盐度的特征,其成矿深度属于中浅成。各成矿阶段包裹体均一温度、成矿流体盐度、成矿流体密度随着成矿作用的进行都具有降低的趋势。在石英中可以发现包裹体沸腾的证据,辉钼矿、黄铁矿等金属矿物沉淀主要是由于流体包裹体的沸腾作用。高岗山钼矿床在矿体特征、矿物组成、矿物组构以及围岩蚀变特征均显示出斑岩型钼矿床的特征。
[Abstract]:The Xiaoxinganling-Zhang Guangxiling metallogenic belt is one of the important molybdenum metallogenic belts in China. The main metallogenic types are porphyry type and skarn type. The porphyry molybdenum deposit in the early Yanshanian early Yanshanian Pacific plate is the first discovered porphyry molybdenum deposit in the Xiaoxinganling-Zhangguangciling metallogenic belt. On the basis of field investigation, a laboratory study of the Gaogangshan molybdenum deposit has been carried out, including the identification of thin sheets, geochemical analysis of rocks and ores, and fluid inclusions testing of ore-forming fluids. The genesis of the deposit is further discussed. The host rock body of the Gao Gang Mountain molybdenum deposit is a small granite rock strain of late Permian, which is controlled by the composite of magmatic rocks, strata, structures and wall rock alteration. The main intrusive rocks in the area are granitic porphyry, porphyry like granite, granodiorite, and ore-forming rock mass is peraluminous. The porphyry granites in the area provide favorable surrounding rock conditions for metallogenesis. The alteration of surrounding rock such as silicification and potassium mineralization controls the ore type, spatial distribution and mineralization strength. The deposit structure is mainly porphyry structure. The ore structure mainly consists of lamellar structure, vein structure, disseminated structure, vein-like structure, vein-like structure, and vein-like structure. The deposit of the Gao Gang mountain molybdenum deposit is similar to the metallogenic stage of typical porphyry molybdenum deposits and is divided into four stages. They are respectively: (I) quartz-potassium feldspar stage (鈪，

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