广西博白三叉冲钨矿床地质特征与成因分析

发布时间：2018-03-11 04:35

本文选题：广西博白三叉冲　切入点：复式花岗岩体　出处：《成都理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：广西博白三叉冲钨矿位于广西陆川米场-博白三滩多金属成矿带内,此成矿带隶属于广西博白-岑溪多金属成矿带的一部分,总体上属于钦杭成矿带的西南段。三叉冲钨矿与矿区燕山期三叉冲复式花岗岩体有密切的成因关系,本文对三叉冲复式岩体和三叉冲钨矿床进行了详细研究,重点探讨了三叉冲复式岩体的地球化学性质、岩浆演化及其与三叉冲钨矿床之间的成因关系。提出了三叉冲钨矿体主要产于岩体与奥陶系中统东冲组(O2d)含灰岩地层的接触带内的矽卡岩体矿化体中,该矿床属于典型的矽卡岩钨矿床,受F5断层控制,矿体呈似层状、脉状产出。围岩蚀变有云英岩化、矽卡岩化、角岩化、硅化等。根据锆石U-Pb同位素测年,可将矿区出露的三叉冲复式花岗岩体可分为两种时代,即主体花岗岩体与补体花岗岩体。其中主体的岩性为中粒黑云母花岗岩,岩体形成时代约为105Ma,补体的岩性为细粒二云母花岗岩,岩体形成时代约为103Ma。三叉冲复式花岗岩体为早期白垩纪的晚期岩浆作用的产物。细粒二云母花岗岩的Na2O和K2O演化趋势岩明显不同于中粒黑云母花岗;且具有更高的CaO和Sr含量;并且,细粒二云母花岗岩的La/Lu比值更高。这些证据证明细粒二云母花岗岩并非中粒黑云母岩通过分离结晶形成,而是玄武岩质岩浆底侵下地壳,引起基底岩石发生新的一次部分熔融的产物,并与幔源基性岩浆发生混合作用后形成的。根据野外地质调查、矿床学、岩石学及地球化学证据,三叉冲钨矿床在成因上与三叉冲复式岩体中的细粒二云母花岗岩密切相关;三叉冲钨矿床是由三叉冲复式岩体岩浆热液活动引发的,同时受北东向断裂造和地层的联合控制形成的矽卡岩型钨矿床。三叉冲钨矿床成矿年龄应该在103Ma或者略为晚点,为早白垩世晚期。
[Abstract]:Bobai Sanchachong tungsten deposit in Guangxi is located in the polymetallic metallogenic belt of Michang-Bobai Santan in Luchuan, Guangxi, which belongs to a part of the polymetallic metallogenic belt of Bobai and Cenxi in Guangxi. Generally speaking, it belongs to the southwestern section of the Qinghang metallogenic belt. There is a close genetic relationship between the Sanjiachong tungsten ore deposit and the Yanshanian Triford-thrust composite granite body in the mining area. In this paper, a detailed study has been carried out on the Sanchangchong complex rock mass and the Sanjianchong tungsten ore deposit. The geo-chemical properties of the trichromatic composite rock mass are discussed in detail. The evolution of magma and its genetic relationship with the Sanjianchong tungsten deposit. It is suggested that the Sanjianchong tungsten orebody mainly occurs in the skarn mineralization in the contact zone between the rock body and the Ordovician middle Ordovician Dongchong formation (O2d) limestone bearing strata. The deposit is a typical skarn tungsten deposit, controlled by F5 fault, and the orebody is stratiform and vein-like. The surrounding rock is altered by quartz, skarn, hornstone, silicification, etc. According to zircon U-Pb isotopic dating, It can be divided into two ages: the main granite body and the complement granite body, in which the lithology of the main body is medium-grained biotite granite. The age of formation of the rock body is about 105 Ma.The lithology of the complement is fine-grained dimite granite. The age of formation of the granites is about 103 Ma.These granites are the product of the late Cretaceous magmatism. The Na2O and K 2O evolution trend rocks of the fine-grained dimicite granites are obviously different from the medium-grained biotite granitic granites and have higher CaO and Sr contents. Moreover, the La/Lu ratio of the granites is higher than that of the granites. These evidences indicate that the granites are not formed by the separation and crystallization of the mesomorphic biotite, but are basaltic magmatic submergence into the lower crust. Resulting in a new partial melting of the basement rock and mixing with the mantle derived basic magma. According to the field geological survey, evidence of ore deposit, petrology and geochemistry, The Sanjianchong tungsten deposit is closely related to the fine-grained dimicite granite in the tri-thrust complex rock mass, which is caused by the magmatic hydrothermal activity of the tri-thrust complex rock mass, the Sanjianchong tungsten ore deposit is closely related to the fine-grained dimicite granite in the tri-thrust complex rock mass. At the same time, the skarn type tungsten deposit formed by the combination of NE fault and strata. The mineralization age of the Sanjianchong tungsten deposit should be at 103 Ma or slightly later, and it is late in the early Cretaceous.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.67

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