贵州大方地区构造特征及构造演化探讨

发布时间：2018-07-21 15:37

【摘要】：大方位于贵州西北部,属黔中隆起部分。区内受多次构造运动影响,区内构造类型齐全,样式复杂。自中生代以来,板块拼接和洋陆俯冲碰撞在区内形成复杂的褶皱系统的断裂体系。特别是自中生代扬子板块和华南板块碰撞拼合以来,区内的构造演化与扬子-华南板块构造演化密不可分。研究区内的构造对研究扬子-华南板块的其他区域地质构造有着现实的科学意义。本文结合现代构造地质学、板块构造学说,通过野外地质调查、室内构造解析等手段,综合前人资料,对其几何学和运动学进行研究,并探讨其古构造应力场和构造演化,取得以下几点认识:1、研究区构造形迹多为北北东向和北东东向,大致沿“鼠场-鸡场-林泉”为界,其北部构造多为北北东向,一般规模较大,褶皱舒缓开阔,发育较多构造穹窿。南部多为北东东向构造,其排列紧密,规模一般不大,见有构造盆地发育。2、研究区褶皱多由弯滑褶皱作用形成,其影响深度有限,为典型的薄皮构造。断层多为逆断层,叠瓦扇式断层组合较为常见,所以本区构造系统应该是由逆冲推覆作用形成的。3、本区构造格局的形成,主要受四个因素控制,一是受区域地质构造背景控制,其总体构造走向与黔中隆起及其邻区相同,其演化历史基本一致;二是本区经历多期次、多性质的构造运动,构造复合-联合作用在本区表现的比较明显;三是构造还受岩石能干性的影响,褶皱多沿二叠系龙潭组泥岩、粉砂岩滑动。四是一定程度上受异常孔隙压力影响。4、燕山中期,受南北向挤压应力,研究区形成一系列近东西向褶皱和断层。燕山末期-喜山早期,研究区主要受到来自太平洋板块和印度板块的共同影响,形成一系列北北东向褶皱和断裂,并叠加于早期北东东向褶皱之上,之后的构造运动使研究区褶皱系统进一步压紧、压扁。
[Abstract]:Generous is located in the northwest of Guizhou, a part of central Guizhou uplift. The area is affected by multiple tectonic movements, the regional structure type is complete, the style is complex. Since the Mesozoic, plate splicing and oceanic subduction collide in the area to form a complex fault system of fold system. Especially since the Mesozoic Yangtze plate and South China plate collided together, the tectonic evolution in the area is closely related to the Yangtze-South China plate tectonic evolution. The tectonics in the study area are of practical scientific significance for the study of other regional geological structures of the Yangtze-South China plate. Combined with modern tectonics and plate tectonics, by means of field geological survey and indoor structural analysis, this paper studies its geometry and kinematics, and discusses its paleotectonic stress field and tectonic evolution. We have obtained the following knowledge: 1: 1. The structural features of the study area are mostly NNE and NW, roughly along the boundary of "rodent farm, chicken farm-Lin Quan," and the northern structures are mostly NNE, generally larger in scale, and generally more relaxed and open in fold. More structural fornix is developed. In the south, most of them are east-west structure, their arrangement is compact, and the scale is not large. There are tectonic basins developed .2. the folds in the study area are mostly formed by curve-slip folds, and their influence depth is limited, which is a typical thin-skinned structure. Most of the faults are reverse faults, and the imbricate fan type fault assemblage is more common. Therefore, the tectonic system in this area should be formed by thrusting and nappe. The formation of the tectonic framework in this area is mainly controlled by four factors, one is controlled by the regional geological tectonic background. Its overall tectonic trend is the same as that of the central Guizhou uplift and its adjacent areas, and its evolution history is basically the same. The third is that the structure is also affected by the rock activity, and the folds slide along the mudstone and siltstone of the Longtan formation of the Permian system. The fourth is influenced by abnormal pore pressure to some extent, and a series of near-east-west folds and faults are formed in the study area during the middle Yanshanian period and under the compression stress of the north-south direction. From the late Yanshanian to the early Himalayan, the study area was mainly influenced by the Pacific plate and the Indian plate, forming a series of NNE folds and faults, which were superimposed on the early east-west fold. The subsequent tectonic movement further compacted and flattened the fold system in the study area.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P542

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