白马洞矿床热液隐爆角砾岩的特征及其与铀成矿的关系

发布时间：2018-03-03 20:03

本文选题：铀矿床　切入点：隐爆角砾岩　出处：《成都理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：贵州白马洞铀多金属矿床是我国典型的碳硅泥岩型铀矿之一。前人对该矿床的成矿地质背景和成因已有较深入的研究,认为控矿构造研究是该区下一步找矿突破的关键。通过详细的野外调查研究,发现该矿床存在热液隐爆系统,对成矿有重要的控制作用。本文在野外地质调查的基础上,通过室内镜下鉴定,常量元素地球化学、微量元素地球化学、稀土元素地球化学、碳氧同位素地球化学等方法,研究了白马洞矿床热液隐爆角砾岩的地质地球化学特征,分析了其与铀成矿的关系,得出以下认识：白马洞铀矿床存在大量与成矿关系密切的角砾岩,根据野外地质观察及室内研究认为这些角砾岩为热液隐爆角砾岩。角砾岩体空间上多呈不规则的囊状、筒状分布,在平面上呈近椭圆形分布,在剖面一般呈漏斗状、筒状分布,热液隐爆角砾岩体从中心向外,破碎程度具有由强到弱的趋势。中心可达碎粉岩,向外由于隐爆作用的能量逐渐变小,逐渐过渡到由热液充填形成的震碎碎裂岩带。黑色蚀变、红色蚀变和热液隐爆角砾岩在空间上的耦合是富大铀矿成矿的部位。矿区围岩与热液脉体的微量及稀土元素组成有明显的差异,碳氧同位素显示黑色蚀变、红色蚀变和热液隐爆角砾岩中方解石脉的流体来源是一致的,具有地幔来源特征；这些方解石脉体与围岩的碳氧同位素组成有着明显的差异,说明白马洞矿床不是围岩在浅表层经沉积、淋滤、改造形成的,而是典型的热液矿床。区域上铀汞多金属成矿有一定的分带性,中高温元素组合富集在东南部,中低温元素组合富集在西北部,暗示成矿流体由深部向浅部、由东南向西北运移的特点。矿区东南部深部成矿潜力较大。
[Abstract]:The Baimadong uranium polymetallic deposit in Guizhou is one of the typical carbon-silicon mudstone type uranium deposits in China. It is considered that the study of ore-controlling structure is the key to the next ore-finding breakthrough in this area. Based on the detailed field investigation, it is found that there is a hydrothermal implosion system in the deposit, which plays an important role in the control of ore-forming. The geological and geochemical characteristics of hydrothermal cryptoexplosion breccia in Baimadong deposit were studied by means of indoor microscopic identification, major element geochemistry, trace element geochemistry, rare earth element geochemistry, carbon and oxygen isotope geochemistry, etc. The relationship between uranium mineralization and Baimadong uranium deposit is analyzed. It is concluded that there are a large number of breccia closely related to uranium mineralization in the Baimadong uranium deposit. According to the field geological observation and laboratory study, these breccia are considered as hydrothermal crypto-explosive breccia. The breccia bodies are usually irregular cystic, tubular and nearly elliptical in plane, and generally funnel-shaped and tubular in profile. The degree of breakage of hydrothermal crypto-explosive breccia is from the center to the weak. The center can reach the comminulitic rock, and the energy of the occult explosion gradually becomes smaller, and gradually transition to the seismic fragmentation zone formed by hydrothermal filling. Black alteration, The spatial coupling of red alteration and hydrothermal cryptoexplosive breccia is the metallogenic position of the uranium rich deposit. The composition of trace and rare earth elements in the surrounding rock and hydrothermal vein of the ore area is obviously different, and the carbon and oxygen isotopes show black alteration. The fluid sources of calcite veins in red alteration and hydrothermal cryptoexplosion breccia are consistent and have the characteristics of mantle origin, and the carbon and oxygen isotopic compositions of these calcite veins are obviously different from those of surrounding rocks. It shows that the Baimadong deposit is not formed by sedimentation, leaching and transformation of surrounding rock on the shallow surface, but is a typical hydrothermal deposit. There is a certain zonation of uranium and mercury polymetallic mineralization in the region, and the element assemblage of medium and high temperature is enriched in the southeast. The element assemblages at middle and low temperatures are enriched in the northwest, implying the characteristics of ore-forming fluid migration from deep to shallow and from southeast to northwest. The ore-forming potential in the southeastern part of the mining area is great.
【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】：P619.14

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