广西大厂矿田构造变形特征及演化过程

发布时间：2018-04-13 13:24

本文选题：演化过程 + 构造剖面恢复　；参考：《昆明理工大学》2017年硕士论文

【摘要】：广西大厂锡多金属矿田位于丹池成矿带的中部,处于滨太平洋和古特提斯喜马拉雅构造域的复合部位,江南古陆的西南缘,海西-印支期被动陆缘裂谷盆地北部的断裂凹陷盆地中。前人对该矿田内的矿床特征、控矿因素及成矿模式进行了深入研究,对矿田构造方面的研究较为薄弱。本文通过对大厂矿田内地表及巷道露头构造形迹的详细调查,以搜集的钻孔资料及前人的研究成果为依据,运用构造解析及古应力状态反演软件对泥盆系各沉积地层内的褶皱、断层及共轭节理进行了解析,揭示了其构造变形特征。因泥盆系地层是加里东期地槽回返后第一个地台沉积盖层,分别从沉积基底和泥盆系盖层两方面对该区的构造演化进行总结,并运用平衡剖面恢复技术对大厂矿田内的泥盆系构造剖面进行了构造演化过程反演,定量分析了矿田的构造运动特征及演化过程。主要认识如下:1.矿田范围内出露的地层主要有泥盆系、石炭系、二叠系及三叠系,其中泥盆系地层分布最为广泛;基本构造格局为北北西向的逆冲断层与紧密褶皱构成的复式褶皱-断裂带、北东向断裂、南北向断裂及东西向褶皱叠加而成的棋盘状构造。2.通过对研究区内的褶皱、断层及共轭节理进行构造解析,可知在地质历史中,该矿田经历了北东向、北北西向、近南北向、北西西向及北北东向的挤压作用,据此划分了两套不同期次的变形样式。其中,北西向线形褶皱、逆冲断层、剪节理等为印支期挤压作用的产物;层间滑脱构造带、石香肠构造、北东向和南北向的张扭性断裂以及近东西向的褶皱构造为燕山期区域拉张作用的产物。3.通过对大厂矿田内的4条构造剖面进行平衡剖面恢复,反演得出在泥盆系纳标组至同车江组沉积期间,大厂矿田所在区域经历的演化过程。即在北东向挤压作用下,整个矿田所在地区长期处于收缩状态。结合莲花山组至塘丁组的拉伸分割阶段及纳标组的平稳沉积阶段,总结出大厂矿田泥盆系地层演化的三步曲。亦即该研究区经历着由动到定,再到动的螺旋状发展的演化过程。
[Abstract]:The Dachang tin polymetallic ore field in Guangxi is located in the middle of the Danchi metallogenic belt, in the composite part of the riparian Pacific Ocean and the PaleoTethys Himalayan tectonic domain, and in the southwestern margin of the Yangtze River.The fault depression in the northern part of the Hercynian-Indosinian passive continental margin rift basin.The ore deposit characteristics, ore-controlling factors and ore-forming model in the ore field have been deeply studied by predecessors, but the study on the structure of the ore field is relatively weak.Based on the detailed investigation of the outcrop structure of the outcrops and the surface of the Dachang Orefield, based on the borehole data collected and the previous research results, this paper applies the software of structural analysis and paleo-stress state inversion to the folds in the depositional strata of the Devonian system.The fault and conjugate joints are analyzed and the structural deformation characteristics are revealed.As the Devonian strata are the first platform sedimentary caprocks after the return of Caledonian geosyncline, the tectonic evolution of the area is summarized from two aspects: sedimentary basement and Devonian caprock, respectively.The structural evolution process of Devonian structural profile in Dachang Orefield is inversed by using balanced section restoration technique, and the tectonic movement characteristics and evolution process of Orefield are quantitatively analyzed.The main ideas are as follows: 1.The strata exposed in the field are mainly Devonian, Carboniferous, Permian and Triassic, in which the Devonian strata are most widely distributed.The chessboard structure formed by NNE fault, NNE fault and EW fold superimposed.Through structural analysis of folds, faults and conjugate joints in the study area, it can be seen that in geological history, the ore field has experienced compressions in the NE, NW, NNE, NW and NNE directions.According to this, two sets of deformation patterns of different periods are divided.Among them, NW linear fold, thrust fault, shear joint and so on are the products of Indosinian compressional process, interlaminar slip zone, stone sausage structure, etc.The tensional and torsional faults and the nearly east-west fold structures in NNE and NNE are the product of regional extension in Yanshanian period.By restoring the balanced sections of four structural sections in the Dachang Orefield, the evolution process of the Dachang Orefield during the depositional period from the Napa formation to the Tongqiejiang formation of the Devonian system is obtained.That is, under the action of N-E compression, the whole ore field is in a long-term contraction state.Combined with the stretching and dividing stage of Lianhuashan formation to Tangding formation and the stable sedimentary stage of Nao-Biao formation, the three-step curve of Devonian stratigraphic evolution in Dachang Orefield was summarized.In other words, the research area has undergone a spiral development from moving to fixed, and then to dynamic.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P613

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