广西全州矿田铀成矿过程

发布时间：2018-04-01 07:57

本文选题：矿床地质　切入点：矿床地球化学　出处：《中国地质大学(北京)》2015年硕士论文

【摘要】：广西全州铀矿田为华南铀成矿区一处典型的碳硅泥岩型铀矿田。本文在广泛收集前人资料的基础上,对该矿田中的典型铀矿床进行了详细的矿床地质和地球化学研究,重点论述了全州铀矿田的成矿条件和形成过程,取得了一些有意义的成果和认识。野外调研和镜下观察结果表明,全州铀矿田主要赋矿地层为中泥盆统信都组近陆源碎屑岩和唐家湾组浅海相碳酸盐岩以及上泥盆统榴江组浅海相碳酸盐岩地层。矿体主要呈似层状和透镜状沿F1和F3层间破碎带分布,其产状与地层和构造产状基本一致。在全州铀矿田各铀矿床中主要有泥质粉砂岩和白云岩两种类型矿石,另有少量构造泥型矿石。泥质粉砂岩型矿石的矿石矿物主要是沥青铀矿、白钨矿和少量晶质铀矿等,脉石矿物主要是石英、绿泥石、高岭石和蒙脱石等;白云岩型矿石的矿石矿物主要为沥青铀矿和白钨矿等,脉石矿物主要为白云石和方解石。钻孔剖面和岩相学资料表明,全州铀矿田内的铀矿床围岩蚀变分布一般较窄,分带不明显。蚀变往往集中于断裂带附近,自矿床边缘往中心部位明显增强。与矿化密切相关的围岩蚀变有赤铁矿化、黄铁矿化、方铅矿化、碳酸盐化、绿泥石化等。根据相互穿插关系、矿物组合和结构构造,可将全州铀矿田铀矿成矿过程分为沉积成岩期、热液期和表生期三个成矿期,其中的热液期又可以进一步分为赤铁矿—沥青铀矿、沥青铀矿—硫化物—方解石、方解石三个阶段。从论文获得的资料来看,全州铀矿田中的铀矿床是典型的沉积-低温热液叠加矿床。在沉积成岩期,加里东期含铀花岗岩的风化、剥蚀和沉积导致区内中上泥盆统地层初步富铀。在热液期,大气降水和地下水通过对富铀地层的淋滤形成了含矿热液,当含矿热液运移到F1、F3层间破碎带时,由于Eh、温度和压力等的改变,铀最终沉淀下来。
[Abstract]:The Quanzhou uranium ore field in Guangxi is a typical carbon-silicon mudstone type uranium ore field in southern China. Based on the extensive collection of previous data, this paper makes a detailed geological and geochemical study of the typical uranium deposit in this ore field. The metallogenic conditions and forming process of Quanzhou uranium ore field are emphatically discussed, and some meaningful results and understandings are obtained. The field investigation and microscopic observation show that, The main ore-bearing strata in Quanzhou uranium ore field are the proximal continental clastic rocks of the Xindu formation of the Middle Devonian, the shallow marine carbonate rocks of the Tangjiawan formation and the shallow marine carbonate rocks of the Upper Devonian Yujiang formation. The orebodies are mainly stratiform and lenticular along F1. And F3 interlaminar fracture zone distribution, Its occurrence is basically consistent with stratigraphic and tectonic occurrence. There are mainly argillaceous siltstone and dolomite ores in each uranium deposit in Quanzhou uranium ore field. In addition, there are a few structural muddy ores. The ore minerals of argillaceous siltstone type are mainly bituminous uranium, scheelite and a small amount of crystalline uranium, etc. The gangue minerals are mainly quartz, chlorite, kaolinite and montmorillonite. The ore minerals of dolomite type ore are mainly bituminous uranium ore and scheelite, while gangue minerals are mainly dolomite and calcite. The borehole profile and petrographic data show that the alteration distribution of surrounding rock of uranium deposit in Quanzhou uranium ore field is generally narrow. The zonation is not obvious. The alteration is usually concentrated near the fault zone and obviously strengthened from the margin to the center of the deposit. The wall rock alteration closely related to mineralization is hematitization, pyrite, galena mineralization, carbonization, etc. According to the intercalation relationship, mineral assemblage and structural structure, the uranium mineralization process in the Quanzhou uranium ore field can be divided into three metallogenic periods: sedimentary diagenetic stage, hydrothermal stage and epigenetic stage. The hydrothermal period can be further divided into three stages: hematite-asphaltene uranium ore, bituminous uranium ore-sulphide-calcite, calcite. The uranium deposit in Quanzhou uranium ore field is a typical deposition-low temperature hydrothermal superposition deposit. During the sedimentary diagenetic period, weathering, denudation and sedimentation of the Caledonian uraniferous granites resulted in the initial enrichment of uranium in the middle and upper Devonian strata in the area. The precipitation and groundwater formed ore-bearing hydrothermal solution by leaching the uranium-rich strata. When the ore-bearing hydrothermal fluid moved to the F _ 1 / F _ 3 interlayer fracture zone, uranium precipitated eventually due to the changes of Eh, temperature and pressure.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P619.14

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