百顺矿田铀矿床地质体地球化学特征研究

发布时间：2018-05-04 03:26

本文选题：百顺铀矿田 + 地质体　；参考：《东华理工大学》2017年硕士论文

【摘要】：本文初步研究了百顺矿田的铀矿床的主量元素、微量元素、稀土元素、稳定同位素的特征,主要取得以下几点认识:主量元素地球化学:通过主量元素地球化学研究,正常花岗岩围岩→蚀变花岗岩→碎裂岩→碎粉岩→硅质脉→富矿石的过程表现为:碱质组分依次逐渐减少,而硅质组分逐渐增加,硅质脉中含量达到最高,然后再减少,表明Si元素在构造带内分布不均。对比8类地质体主量元素组成及其变化规律,除碎粉岩外,其他不同地质体中Al_2O_3、Na_2O、K_2O、MgO、TiO_2、P_2O_5与SiO_2表现较为明显的正相关关系;TFe_2O_3、FeO与SiO_2表现为明显的负相关关系;CaO与MnO含量基本保持平稳。辉绿岩与其他地质体的物质成分明显不同。除辉绿岩外,其他地质体物质成分与围岩具有良好的相似性和继承性。微量元素地球化学:正常花岗岩围岩、蚀变花岗岩、碎裂岩、碎粒岩、碎粉岩、硅质脉、富矿石、萤石、方解石中高度相容元素Cr、Co和Ni的含量很低,与富集Cr、Co、Ni等高度相容元素相比差异明显。这些高度相容元素组分主要来源于花岗岩而不是地幔,暗示百顺矿田铀矿床成矿物质和成矿热液可能来自围岩花岗岩。稀土元素地球化学:地质体的稀土元素特征曲线大致可分为四类:1、正常花岗岩、蚀变花岩石、碎裂岩、碎粒岩、萤石和方解石的曲线呈右倾型,轻稀土元素富集;Eu负异常,铕亏损明显;轻、重稀土元素之间的分馏程度较高;2、富矿石:稀土元素总量是所有地质体中最高的;Eu负异常,铕亏损明显;与图中其他曲线均呈明显右倾不同,富矿石的稀土元素特征曲线接近水平,表明重稀土元素趋于富集,轻、重稀土元素之间的分馏作用大为减弱。3、硅质脉和碎粉岩:二者的曲线呈右倾型且稀土元素总量最低;Eu负异常,铕亏损明显;与其他曲线不同的是,二者均呈现明显的Ce亏损。4、辉绿岩:辉绿岩稀土配分模式曲线呈右倾型,但无Eu异常,这点表明它与其余几种地质体在来源方面有着本质的不同。萤石和方解石稀土元素的特征表明,铀矿床中的成矿物质和热液流体主要来源于Eu相对亏损的围岩花岗岩。稳定同位素:氢氧同位素组成特征,百顺矿田铀矿床成矿的热液流体主要来自于大气降水补给的地下水演化形成,并与周围的岩石发生氧同位素的交换反应;方解石中碳氧同位素特征表明成矿热液流体中的碳来源于花岗岩,并混入了部分的沉积有机碳。
[Abstract]:In this paper, the characteristics of principal elements, trace elements, rare earth elements and stable isotopes of uranium deposits in Baishun Orefield have been preliminarily studied. The main conclusions are as follows: principal element geochemistry: through the study of principal element geochemistry, The process of alteration of granitic rock in normal granite rock is as follows: the alkali component decreases gradually, while the siliceous component increases gradually, the content of siliceous vein reaches the highest and then decreases. The results show that Si is unevenly distributed in the tectonic zone. Comparing with the principal element composition and its variation law of 8 kinds of geological bodies, with the exception of comminuted rocks, there is an obvious positive correlation between the contents of Cao and MnO in other geological bodies, except for the crushed rocks, the positive correlation between the contents of Cao and MnO is obvious, the relationship between the contents of Cao and MnO is basically stable. The material composition of diabase is obviously different from that of other geological bodies. With the exception of diabase, other geological bodies have good similarity and inheritance with surrounding rock. Trace element geochemistry: the contents of highly compatible elements Cr-Co and Ni in normal granite surrounding rock, altered granite, cataclastic rock, granulite, shredded rock, siliceous vein, rich ore, fluorite and calcite are very low. The difference is obvious compared with the enrichment of highly compatible elements such as Cr-Co-Ni. These highly compatible elements are mainly derived from granites rather than the mantle suggesting that the ore-forming minerals and ore-forming hydrothermal fluids of the Beshun Orefield uranium deposit may come from the surrounding granite. REE geochemistry: the REE characteristic curves of geological bodies can be roughly divided into four categories: 1: 1. The curves of normal granite, altered rock, clastic rock, granulite, fluorite and calcite are right-dip, and the REE is enriched with negative EU anomaly. Europium depletion is obvious, the fractionation degree between light and heavy rare earth elements is higher than 2, rich ore: the total amount of rare earth elements is the highest negative anomaly of EU in all geological bodies, and the EU depletion is obvious, which is different from the other curves in the diagram. The REE characteristic curve of the ore is close to the level, indicating that the heavy REE tends to be enriched and light. The fractionation between heavy rare earth elements is greatly weakened. 3. Siliceous veins and crushed rocks. The curves of the two have the right dip type and the lowest EU negative anomaly in the total amount of rare earth elements, and the europium depletion is obvious, which is different from the other curves. The REE distribution pattern curve of diabase: diabase is right dip, but there is no EU anomaly, which indicates that it is essentially different from other geological bodies in source. The characteristics of rare earth elements in fluorite and calcite indicate that the ore-forming materials and hydrothermal fluids in the uranium deposit are mainly derived from the EU depleted surrounding rock granites. Stable isotopes: the characteristics of hydrogen and oxygen isotopic composition, the hydrothermal fluid of uranium deposit in Baishun Orefield mainly comes from the evolution of groundwater recharge by atmospheric precipitation and the exchange reaction of oxygen isotopes with surrounding rocks; The carbon and oxygen isotopic characteristics of calcite indicate that the carbon in ore-forming hydrothermal fluid originated from granite and mixed with part of sedimentary organic carbon.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P619.14

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