百顺铀矿田构造应力场特征及其与铀成矿关系

发布时间：2018-04-11 21:06

本文选题：百顺铀矿田 + 构造应力场　；参考：《东华理工大学》2016年硕士论文

【摘要】：通过百顺矿田主要成矿构造野外露头蚀变构造岩观察、钻孔岩心构造岩观察、脉体和胶结物穿插关系的分析,系统地划分了它们的活动期次。在野外对研究区内各不同时代岩体和断裂带中的节理和擦痕滑动面进行了大量观测和分析,共获得26个节理统计点配套的64组次生共轭节理和50余组节理面或断裂面擦痕矢量数据,主要利用共轭剪节理法和擦痕矢量数据反演法,通过吴氏网分析和计算机软件计算,反演三维点应力状态。将研究区的构造应力场划分为4个期次,结合区域构造演化和矿区地质特征,探讨了各期次构造应力场与铀成矿作用关系。主要取得以下几点结论和认识。(1)NE向区域导矿和控矿断裂构造早期主要为左行压扭构造,形成了磨圆度较好的碎裂岩;中期为2~3次的NW-SE向伸展正断作用,形成张性角砾岩,伴随有多期次灰白色—红色或杂色的玉髓胶结;晚期断裂面擦痕和阶步显示右行压扭特征,形成未胶结或胶结不好的断层泥和断层泥砾。近SN向的储矿和容矿构造总体经历了早期张扭性和晚期张性两次主要构造活动,早期局部有一定磨圆度的角砾显示张扭性特征;晚期张性构造活动控制了带内铀矿化产出。(2)百顺铀矿田地区先后至少经历了NW-SE向近水平构造挤压作用、近SN向近水平的构造挤压作用、NW-SE向伸展构造作用和近EW向近水平的构造挤压作用4期构造应力场作用。早期NW-SE向挤压构造作用对应为燕山早期(晚侏罗世)的挤压构造事件;近SN向挤压构造作用对应为燕山晚期(早晚白垩世之交时期)的挤压构造事件;NW-SE向伸展构造作用对应为燕山晚期(晚白垩世)的伸展构造事件;晚期近EW向挤压构造作用对应为喜山期的挤压构造事件。(3)在NW-SE向挤压构造作用下,产生的NE向区域性断裂等为后期区内铀成矿提供了必要的构造通道条件;在近SN向挤压构造作用下,区内NE向断裂构造产生左行压扭,派生了一系列近SN向张性构造,并使得近SN向构造产生早期张扭活动,为成矿期含铀热液富集成矿提供了有利条件;NW-SE向伸展构造作用,使区域性NE向断裂产生拉张,近SN向断裂产生晚期的再次拉张,该期导通断裂深部的构造和流体作用是形成区内铀矿化的最重要阶段;近EW向挤压构造作用可能对早已期形成的铀矿化产生破坏或改造作用。(4)牛澜断裂带是区域性的控矿构造,也为导矿、储矿构造;次级烟筒岭断裂是区内主要导矿构造,也为储矿构造;更次一级的近SN向张性构造是区内最主要的储矿构造。近SN向构造遭受了多次张性构造活动,使其成为区内铀成矿最有利的构造部位,可作为区内下一步铀矿勘查找矿的主攻方向。
[Abstract]:Based on the observation of the main ore-forming structures in the Baishun Orefield, the observation of the outcrop altered tectonics in the field, the observation of the tectonic rocks in the borehole core, and the analysis of the relationship between the veins and the cementation, the active periods of the main ore-forming structures are systematically divided.In the field, a large number of joint and scratch sliding surfaces of rock masses and fault zones in different ages in the study area were observed and analyzed.A total of 64 groups of secondary conjugate joints and more than 50 sets of scratch vector data of joint or fault surface were obtained from 26 statistical points of joint. The method of conjugate shear joint and the inversion method of scratch mark vector data were mainly used, and the analysis of Wu's net and the calculation of computer software were carried out.Inversion of three dimensional point stress state.The tectonic stress field in the study area is divided into four periods. The relationship between the tectonic stress field and uranium mineralization is discussed in combination with the regional tectonic evolution and the geological characteristics of the mining area.The main conclusions and understandings are as follows: the early stage of the ore-conducting and ore-controlling faults in the NE trending area is mainly left-lateral compression-torsional structure, which formed a good grinding roundness of clastic rock, and the NW-SE extensional positive fault in the middle stage of 2 times, resulting in tensional breccia, is the main one in the early stage of the ore-controlling fault structure.The grayish-red or variegated chalcedony cementation is accompanied by several phases, and the late fracture surface marks and steps show the characteristics of right-line compression and torsion, resulting in uncemented or poorly cemented fault gouges and gouge.The ore-storage and ore-bearing structures in the near SN direction generally experienced two main tectonic activities: the early tension-torsion and the late tensionality, and the early local breccia showed the characteristics of tension-torsion with a certain degree of grinding roundness.The late tensional tectonic activity controlled uranium mineralization in the belt.The NW-SE extensional tectonics and the near-EW near-horizontal tectonic compressions in the near SN direction of tectonic compressions are responsible for the tectonic stress field in the fourth stage.The early NW-SE compressional tectonics correspond to the early Yanshanian (late Jurassic) compressional tectonic events.The NW-SE extensional tectonic event corresponds to the late Yanshanian (late Cretaceous) extensional tectonics. The NW-SE extensional tectonic event corresponds to the late Yanshanian (late Cretaceous) extensional tectonic event.The late EW compressional tectonics correspond to the compressional tectonic event of the Himalayan period. Under the action of NW-SE compressional tectonics, the NE trending regional faults provide the necessary tectonic channel conditions for uranium mineralization in the late area.Under the action of the near SN compression structure, the NE trending fault structure in the area produces a series of near SN trending tensional structures, resulting in the early tensional activity of the near SN trending structures.This provides favorable conditions for the enrichment and mineralization of uranium-bearing hydrothermal solution during the metallogenic period, resulting in the extension of regional NE trending faults and the reextension of the late stage of the near SN trending faults, and the NW-SE extensional tectonics.The tectonic and fluid processes in the depth of the conducting fault are the most important stage of uranium mineralization in this area, and the near EW compressional tectonism may destroy or transform the uranium mineralization formed in the early period. The Niulan fault zone is a regional ore-controlling structure.The sub-Yanchongling fault is the main ore-conducting structure in the area and is also the ore-storage structure, and the next order near-SN tensional structure is the most important ore-storage structure in the area.The near SN trending structure has been subjected to many tensional tectonic activities, which makes it the most favorable tectonic position for uranium mineralization in this area, and can be regarded as the main direction of uranium exploration and prospecting in this area.
【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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