百顺铀矿田矿床地球化学特征及成因探讨

发布时间：2018-04-26 09:58

  本文选题：诸广岩体 + 百顺矿田　； 参考：《东华理工大学》2015年硕士论文

【摘要】：百顺矿田位于诸广岩体南部,是华南花岗岩型铀矿的典型代表。本文在野外地质调查、取样和分析的基础上,结合前人的研究成果,系统分析了区内主要铀矿床的主量、微量、稀土元素,氢、氧、碳、硫以及铅等同位素的组成特征,对百顺铀矿田矿床的成矿流体和成矿物质来源进行了探讨,主要取得了以下几点认识:(1)对比围岩花岗岩、近矿蚀变岩石、富矿石以及辉绿岩的主量元素组成,发现他们之间存在着一定的规律性,矿石中的物质成分对围岩有良好的继承性,其主量元素组成与花岗岩关系更相似,而与辉绿岩明显不同,这表明矿石与花岗岩的组成物质具有同源性;稀土、微量元素分析显示,区内花岗岩U含量较高,有较强供铀能力;对比矿田内不同地质体的稀土、微量元素组成,花岗岩、蚀变岩、碎粉岩、硅质脉、富矿石的微量元素标准化曲线一致性较好,但与辉绿岩脉差异明显,认为成矿物质很来自围岩花岗岩;(2)采集了区内多个矿床和矿点中无矿化新鲜辉绿岩、含矿破碎辉绿岩、含矿硅质脉以及花岗质碎裂岩富矿石等24个黄铁矿样品,并测试了样品中黄铁矿的硫同位素组成,其中富矿石中黄铁矿的δ34SCDT值为-18.9‰~-17.3‰,破碎的矿化辉绿岩为-6.5‰~-10.9‰,两者与新鲜辉绿岩中黄铁矿的δ34SCDT值(-0.5‰~-0.2‰)明显不同,表明成矿流体中硫来自幔源的可能性很小,而与花岗岩中的硫或生物成因硫一致;(3)收集了41个样品的氢氧同位素数据,δD-δ18OH2O投图结果显示所有氢、氧同位素值均落于地幔水、岩浆水、变质水与大气降水线之间,进一步判别表明成矿流体来自大气降水;(4)测试的30个方解石样品的碳同位素分析表明,各矿床成矿期流体的δ13CPDB值为-10.25‰~-4.56‰,接近于华南花岗岩或地幔碳同位素组成,进一步的碳氧同位素投图表明碳也可以来自花岗岩;(5)富矿石和花岗岩的铅同位素组成特征显示它们均来自上地壳。综上所述,百顺铀矿田的成矿物质和流体可能主要来源于大气降水沿深大断裂的循环并萃取围岩花岗岩中各种成矿元素而形成。
[Abstract]:The Baishun Orefield is located in the southern part of the Guang rock mass and is a typical representative of the granitic uranium deposits in South China. On the basis of field geological survey, sampling and analysis, and combining with the previous research results, this paper systematically analyses the main quantities, trace, rare earth elements, hydrogen, oxygen, carbon, sulfur and lead isotopes of the main uranium deposits in the area. The source of ore-forming fluid and ore-forming material in the Beshun uranium ore field is discussed. The main contents of ore-forming fluids and ore-forming materials in the Beshun uranium deposit are compared as follows: (1) the main elements of the surrounding rock granite, the near-ore altered rock, the rich ore and the diabase. It is found that there is a certain regularity between them. The mineral composition in the ore has a good inheritance to the surrounding rock, and its principal element composition is more similar to that of the granite, but it is obviously different from the diabase. The analysis of rare earth elements and trace elements shows that the U content of granites in the area is relatively high and the uranium supply ability is strong, and the composition of rare earth, trace elements, granites, and granites in different geological bodies in the ore field are compared with each other. The standardized curves of trace elements in altered rocks, crushed rocks, siliceous veins and rich ores are consistent, but are different from those of diabase veins. It is considered that the ore-forming material is derived from the surrounding rock granitoids.) Twenty-four samples of pyrite, such as non-mineralized fresh diabase, ore-bearing broken diabase, ore-bearing siliceous vein and granitic clastic rock rich ore, have been collected from several deposits and ore sites in the area. The sulfur isotopic compositions of pyrite in the samples were tested. The 未 34SCDT values of pyrite in rich ores were -18.9 鈥，

本文编号：1805529