冀北张麻井铀钼矿床地质特征及成矿规律

发布时间：2018-01-30 16:50

本文关键词： 铀矿床火山机构流纹斑岩成矿规律　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：张麻井铀钼矿床是我国北方重要的铀矿床,位于华北陆块北缘,属于燕辽成矿带的西段。本文依托《华北陆块北缘铀多金属矿综合评价技术研究》项目,对张麻井矿床进行地质特征及成矿规律研究。在野外地质调查及前人资料基础之上,对矿床的赋矿围岩、构造格架、矿体特征、矿石学特征、围岩蚀变特征及元素地球化学特征进行了系统研究;厘定了成矿时代,讨论成矿物质来源与矿床成因,总结成矿规律。主要研究成果如下:(1)张麻井矿床的铀主要来源于张家口组三段火山熔岩及碎屑岩与流纹斑岩,二者同为壳源重熔产物,为矿床的主要赋矿围岩。(2)构造格架是矿床形成的重要前提条件。断裂F45控制区域地层、矿床及火山机构的分布,与次级断裂F3交汇部位的火山机构有流纹斑岩体侵入,也为成矿流体提供运移通道及容矿空间。(3)张麻井矿床围岩蚀变有多种类型,中低温矿物共存,且具有分带特征,大致可以划为钾化带、泥化带和硅化-褐铁矿化带。(4)矿石中Fe、Ti、Mn、P元素相对富集,U与In、Bi、Be、Cr、Co、Ni、V、Cu、Sc、Cs、Ga、Th、Zn等元素具有一定的相关性,与流纹岩及流纹斑岩相比矿石具有更为明显的Eu异常。(5)张麻井矿床铀分为三个成矿期:第一期铀成矿与流纹斑岩的形成密切相关;第二期铀成矿属于热液脉型;第三期铀成矿是对第一期铀矿体的次生富集,属淋滤型。(6)控矿主断裂与次级断裂结点上的火山机构+(超)浅成斑岩体+张家口组三段火山岩系这种多地质要素的耦合是张麻井矿床铀成矿的关键。
[Abstract]:The Zhangmajing uranium and molybdenum deposit is an important uranium deposit in the north of China, which is located in the northern margin of the North China continent and belongs to the western section of the Yanliao metallogenic belt. On the basis of field geological investigation and previous data, the ore-bearing surrounding rock, tectonic framework, orebody characteristics and mineralogical characteristics of the deposit are studied. The alteration characteristics and element geochemical characteristics of surrounding rock are systematically studied. The metallogenic age is determined and the source of ore-forming material and the genesis of the deposit are discussed. The uranium of Zhangmajing deposit is mainly derived from volcanic lava, clastic rock and stream porphyry in the third member of Zhangjiakou formation, both of which are the product of crust-source remelting. The tectonic framework is an important prerequisite for the formation of the deposit. The fault F45 controls the distribution of regional strata, deposits and volcanic bodies. The volcanic mechanism at the junction of the secondary fault F3 has the intrusions of the fluvial porphyry, and also provides the migration passage and the ore-bearing space for the ore-forming fluid. There are many types of alteration in the surrounding rock of the Zhangma well deposit, and the intermediate-low temperature minerals coexist. The ore is characterized by zonation, which can be divided into potassium zone, mudding zone and silication-limonitization zone. There is a certain correlation between the elements such as CsGa-Th Zn and so on. Compared with rhyolite and rhyolitic porphyry, the ore has more obvious EU anomaly. 5) uranium deposit in Zhangmai well is divided into three metallogenic periods: the first stage of uranium mineralization is closely related to the formation of fluid porphyry; The second stage of uranium mineralization belongs to hydrothermal vein type; The third stage of uranium mineralization is secondary enrichment of the first stage uranium orebody. The coupling of the volcanic rocks of the third member of Zhangjiakou formation is the key to uranium mineralization in the Zhangmajing deposit, which belongs to the leaching type. The volcanic mechanism (ultra) on the node of the main fault and the secondary fault is the coupling of the volcanic rock series of the third member of Zhangjiakou formation.
【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;P618.65

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