相山邹家山铀矿床地球化学研究

发布时间：2018-03-14 15:22

本文选题：邹家山铀矿床　切入点：热液蚀变　出处：《东华理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：邹家山铀矿床是我国知名火山岩型相山铀矿田中的最重要矿床之一,也是目前相山铀矿田中铀资源量最多的铀矿床。邹家山矿床位于相山铀矿田西北部,矿床是典型的受构造控制的热液铀矿床。矿床成因复杂,目前在热液来源与成矿物质来源问题上仍然存在较大的争议。本文通过野外地质调查及取样、钻孔岩芯观察,从宏观上对矿床的构造、蚀变特点、矿石特征、矿体赋存部位等进行了分析。通过显微镜下薄片观察研究、扫描电镜观察分析、电子探针分析、化学成分析等,对成矿有利的蚀变类型、铀矿物赋存类型及赋存特征、矿石及围岩的主微量元素地球化学特征等进行了系统研究。总结了该矿床的成矿地质特征和矿床地球化学特征,主要取得以下几点认识:(1)邹家山铀矿床成矿作用受构造裂隙严格控制,热液蚀变见明显分带现象。矿床蚀变种类多样,热液活动频繁,与成矿有关的蚀变现象有:水云母化、萤石化、绿泥石化、黄铁矿化等。酸性蚀变期是主要的成矿期。(2)铀矿物产出主要有沥青铀矿、钛铀矿、铀-钍石等,在野外工作中也可见一些次生铀矿物,但并不是主要的产出形式。与铀矿共存的矿物有磷灰石、磷钇矿、黄铁矿、萤石等,暗色矿物中也存在以吸附形式存在的铀矿物,主要在暗色矿物表面或是边缘产出。(3)从蚀变围岩至矿石,U、Al_2O_3、MgO、CaO、P_2O_5含量逐渐升高,烧失量也呈升高趋势。从未蚀变碎斑熔岩至矿石SiO_2的含量是呈递减趋势,随着深度的增加,MgO的平均含量呈升高的趋势。虽然样品K_2O整体含量要高于Na_2O,但从矿石中Na_2O含量高于其K_2O的含量得出,铀成矿作用可能与钠交代关系更加密切。(4)成矿元素U、Th含量从蚀变围岩到矿石呈递增的趋势,Th的含量随着U的含量升高而升高,两者呈正相关关系。而Rb、Ba、Sr、P、Ti含量变化范围较大,矿石中Th/U比值较蚀变围岩降低,得出成矿过程中Th、U发生了分异,也反应了U发生了活化转移。(5)从蚀变围岩至矿石稀土元素总量呈增加的趋势,矿石相对蚀变围岩重稀土元素更富集,且随深度增加,重稀土元素更为富集。矿石LREE/HREE比值在1.03-6.21之间,平均值为3.20;蚀变围岩LREE/HREE比值在1.17-8.99之间,平均值为5.18;未蚀变碎斑熔岩LREE/HREE比值在4.60-8.34之间,平均值为5.588,表明热液分异演化程度与铀富集存在密切关系。Eu元素的负异常说明成矿热液具有深部来源。
[Abstract]:The Zoujiashan uranium deposit is one of the most important deposits in the well-known volcanic type of Xiangshan uranium ore field in China, and is also the most abundant uranium deposit in the Xiangshan uranium ore field at present. The Zoujiashan uranium deposit is located in the northwest of Xiangshan uranium ore field. The deposit is a typical hydrothermal uranium deposit controlled by structure. The genesis of the deposit is complex and there is still a great deal of controversy on the source of hydrothermal solution and the source of ore-forming material. In this paper, through field geological investigation and sampling, the borehole core is observed. The structure, alteration characteristics, ore characteristics and the occurrence of ore body are analyzed from the macroscopic view. The thin slice observation under microscope, SEM observation and analysis, electron probe analysis, chemical analysis and so on are carried out. The favorable alteration types of mineralization, the occurrence types and characteristics of uranium deposits, the geochemical characteristics of main and trace elements of ore and surrounding rock are systematically studied, and the metallogenic geological characteristics and geochemical characteristics of the deposits are summarized. The main conclusions are as follows: (1) mineralization of Zoujiashan uranium deposit is strictly controlled by tectonic fissures, and obvious zonation of hydrothermal alteration is observed. The alteration types of deposit are various, hydrothermal activity is frequent, and the alteration phenomena related to mineralization are hydromica, hydromica and hydromica. The acid alteration stage is the main metallogenic stage. The uranium deposits are mainly produced from bituminous uranium, titanium uranium, uranium-thorium and so on. Some secondary uranium minerals can also be found in field work. The minerals coexisting with uranium deposits include apatite, yttrium phosphate, pyrite, fluorite, etc. Mainly produced on the surface or edge of dark mineral, the content of SiO_2 from the altered rock to the ore is gradually increasing, and the amount of burning loss is also increasing. The content of SiO_2 from the never altered macular lava to the ore is decreasing. The average content of Na_2O increased with the increase of depth. Although the total content of K _ 2O in the sample is higher than that of NaS _ 2O, it is obtained from the fact that the content of Na_2O is higher than that of K _ 2O in the ore. Uranium mineralization may be more closely related to sodium metasomatism. (4) the content of uranium Th is increasing from altered rock to ore. The content of Th increases with the increase of U content, and there is a positive correlation between them. The ratio of Th/U in the ore is lower than that in the altered rock. It is concluded that there is a differentiation of Thu in the metallogenic process, which also reflects the increasing trend from the altered wall rock to the total amount of rare earth elements in the ore from the altered rock to the total rare earth element of the ore. The ore is relatively enriched in heavy rare earth elements in altered surrounding rock, and the LREE/HREE ratio of ore is 1.03-6.21, the average value is 3.20, and the LREE/HREE ratio of altered surrounding rock is between 1.17-8.99 with the increase of depth, the ore LREE/HREE ratio is between 1.03-6.21, the average value is 3.20, and the LREE/HREE ratio of altered rock is 1.17-8.99. The average value is 5.18 and the LREE/HREE ratio of unaltered patchy lava is between 4.60-8.34 and 5.588respectively, indicating that there is a close relationship between the evolution of hydrothermal differentiation and uranium enrichment. The negative anomalies of EU element indicate that the ore-forming hydrothermal solution has deep source.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P619.14

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