江西省大余县高坪地区构造与铀成矿关系研究

发布时间：2018-03-29 17:40

本文选题：构造控矿　切入点：晚期脉岩　出处：《核工业北京地质研究院》2015年硕士论文

【摘要】：论文在前人研究工作的基础上,突出了断裂构造对区内铀成矿的影响,着重对断裂构造进行了野外地质调研和室内显微构造分析,大致查明了区内主要断裂的几何学、运动学特征。通过本区古构造应力场、同构造期脉岩和构造样式及穿插关系等的研究,分析了区内主要断裂的演化过程。利用断裂带内构造岩地球化学特征,大致阐明了区内黄溪断裂和成功坳断裂物质组分的迁移特征。结合深部钻探工程获得的钻孔资料及近些年最新研究成果,对区内断裂活动时序与铀成矿关系进行初步探讨。通过两年的研究工作,取得以下主要成果和认识:(1)高坪石寨地区分布着两条较大规模的NNW向断裂蚀变带(6号带和8号带)及其次级断裂,而不是几组小规模的NNW向裂隙。其中,石寨地区6号带西侧250米处沿沟发育一条NNW向硅化带,即8号带,该条硅化带与石寨地区近SN向铀分量高值异常晕相吻合,具有较好的找矿前景。(2)高坪地区中部近SN向断裂蚀变带,即9号带,该处构造活动次序较为复杂,近SN向断裂蚀变带被NEE向黄溪次级断裂错断,且产状变化较大。(3)利用锆石LA-ICP-MS U-Pb同位素定年法和晶质铀矿U-Pb同位素定年方法对高坪地区钻孔揭露的细粒花岗岩脉进行“平行定年”。研究结果表明,该区大多数钻孔揭露的细粒花岗岩脉形成于印支早期,而不是前人所认识的燕山晚期,并证实该区受印支期SN向挤压构造活动的影响。(4)结合野外地质调查和室内综合分析成果,从三个方面分析了高坪地区断裂构造对铀成矿的控制作用。①构造活动序次对铀成矿阶段的控制,即矿液在不同构造应力场下运移的方向不同;②NEE向黄溪断裂扭性构造结构面有利于矿液的运移与沉淀,后期若伴随张性活动,更利于富大铀矿体的形成;③近SN向断裂力学性质及运动方式因构造应力场的变化而改变,形成有利于铀成矿的地段。最后,充分利用已有的各种地质、物化探等资料,在野外综合地质调查的基础上,预测黄溪断裂带东段深部、黄溪断裂带中段和石寨地区NNW向断裂蚀变带为铀成矿有利远景区,建议开展钻探揭露与查证工程。
[Abstract]:On the basis of previous research work, this paper highlights the influence of fault structure on uranium mineralization in the area, and focuses on the field geological investigation and indoor microstructural analysis of the fault structure, and roughly finds out the geometry of the main faults in the area. Based on the study of paleotectonic stress field, dike rock and tectonic style and intercalation relationship in the same tectonic period, the evolution of major faults in this area is analyzed. The geochemical characteristics of tectonite in the fault zone are used. The migration characteristics of material components of Huangxi fault and Chengde depression in this area are described, combined with the drilling data obtained from deep drilling projects and the latest research results in recent years. The relationship between the sequence of fault activity and uranium mineralization in this area is discussed. Two large scale NNW trending fault-alteration zones (zone 6 and zone 8) and their secondary faults are distributed in the Gaoping Shizhai area, instead of several small scale NNW trending fissures. In Shizhai area, a NNW silicification zone is developed along the gully 250m to the west of the No. 6 belt in Shizhai area. The silicification zone coincides with the high value anomaly halo of uranium in the near SN direction in Shizhai area. In the middle of Gaoping area, near SN trending fault alteration zone, I. e., zone 9, where the sequence of tectonic activity is more complicated, the near SN trending fault alteration zone is faulted by NEE direction Huangxi secondary fault. LA-ICP-MS U-Pb isotopic dating method of zircon and U-Pb isotopic dating method of crystalline uranium ore are used to determine the "parallel dating" of granitic veins exposed by boreholes in Gaoping area. Most of the fine-grained granite veins exposed by boreholes in the area were formed in the early Indosinian period rather than in the late Yanshanian known by previous people, and it is confirmed that this area was influenced by the SN compressional tectonic activity in the Indosinian period. From three aspects, the controlling effect of fault structure on uranium mineralization in Gaoping area is analyzed. 1 the control of tectonic activity order on uranium metallogenic stage is analyzed. In other words, the direction of migration of ore fluid under different tectonic stress fields is different. The torsional structural plane of Huangxi fault is favorable to the migration and sedimentation of ore fluid, and if it is accompanied by tensional activity in the later stage, It is more favorable for the formation of large uranium orebodies to change the mechanical properties and movement patterns of the near SN direction faults due to the change of tectonic stress field, and to form a favorable uranium metallogenic area. Finally, the available geological, geophysical and geochemical exploration data are fully utilized. On the basis of comprehensive geological investigation in the field, it is predicted that the deep part of the eastern section of the Huangxi fault zone, the NNW trending fault alteration zone in the middle section of the Huangxi fault zone and the Shizhai area are favorable areas for uranium mineralization. It is suggested that the project of drilling disclosure and verification should be carried out.
【学位授予单位】：核工业北京地质研究院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P619.14;P548

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