【作者】 周永刚；

【导师】 李三忠；

【作者基本信息】 中国海洋大学 ， 海洋地质， 2009， 硕士

【摘要】 中上扬子地区区内地质构造现象复杂,尤其是中、新生代的复杂褶皱和逆冲推覆构造在该区的展布和组合格局是研究陆内造山活动的天然实例。地质构造的研究是突破整个华南大地构造的关键,然而多年来对该区的研究不够深入,看法各异,尚未形成统一的理论和认识。本文以遥感技术(RS)为手段,以地理信息系统(GIS)为平台,结合有限元分析,充分突出3S(RS、GIS、GPS)技术在地质构造研究中的重要性,选取典型区域进行精细的遥感解析,并建立Shaded Relief Model(SRM),试图通过浅部特征来揭示中上扬子地区浅层构造的几何学和运动学特征,并在此基础上探讨其可能的动力学成因和演化。通过对典型区域褶皱和断裂的研究,得出结论如下:1.通过对典型区域浅层褶皱系统的分析,发现雪峰山东西两侧构造系统各异,筛分出雪峰山东侧各期次对应的褶皱及主要特征:加里东运动在雪峰山东侧形成了东西向的构造;印支运动造就了雪峰山东侧褶皱系统的构造雏形,印支运动主要有两幕,第一幕形成了近东西向的构造;第二幕形成了指向北西的弧形褶皱。雪峰山西侧筛分出的褶皱及特征:主要识别出三幕褶皱都是发生于燕山期,分别为:第一幕形成了一系列东西向构造;第二幕以形成一系列北东向构造为主,局部由于大断裂的控制作用,导致部分地区应力场发生异常,形成网眼状构造等;第三幕主要发育了延伸稳定的南北向构造。2.通过对川东、川东南地区褶皱样式和组合规律的分析,认为在挤压环境下,当发生构造联合,或先存构造线强烈影响后期构造活动时,褶皱的生长和形成过程都表现出明显的趋同性。同样的规律也体现在断裂的生长和形成过程中。3.通过对中上扬子地区典型区域的研究总结出一套通过分析褶皱迹线和节理系统,区分构造复合、联合的遥感地质研究方法。4.通过对中上扬子地区构造几何学和运动学的分析,推测可能的动力学机制,即印支期可能由于华北板块和华南板块沿着商丹带和勉略带斜向碰撞,产生了巨大挤压,在雪峰山东侧产生了东西向的构造线,随后逐渐往西侧闭合,在雪峰山主体及西侧主要表现为沿边界展布的弧形构造线,往南扩展较近。后期扬子地块与华夏地块碰撞又发生了一次北西向的挤压,产生了向北西凸出弧形构造线。燕山二幕的形成与依佐奈琦古板块和古太平洋板块向扬子斜向俯冲有关,在雪峰山东侧仍然表现为弧形构造,而在雪峰山西侧表现为一系列沿雪峰山边界展布的弧形构造及西侧的北东向构造。燕山三幕的形成可能与太平洋板块变换方向和角度,由东向西向扬子板块俯冲有关。更多还原

【Abstract】 There are lots of complex geological structures in the Middle and Upper Yangtze (carton) region. This is one good natural laboratory to study intra-continental orogeny, especially for complex folds and thrust belts. The researches to them are keys to reveal structures in South China. However, there are a little study in this important area to oil-gas exploration. Different scientific ideas are split. Therefore, this thesis tries to reveal structural geometry and kinematics by the superficial characteristics using method of remote sensing technology which is based on Geographics Information System platform and finite element analysis. This paper stresses an importance of 3S technologies in structure geology. In order to do this, this research chooses some typical structural regions and creates the Shaded Relief Model to the study of folds and fractures in those typical regions. Finally, four conclusions as follows have been made.1. There are some different structures between the east and west sides of the Xuefeng mountain after analyzing the fold-systems of typical regions in detail. In the east side of the Xuefeng mountain, EW-trending folds formed in the Caledonian movement, then being superposed in the Indosinian movement which can be subdivided into two stages: the first-stage were EW-trending folding, and the second-stage northwestward-convexed thrusting to form arc-like structures; On the other hand, deformation in the west side of the Xuefeng mountain can be also subdivided into two-stage folding and one-stage strike-slipping, which occured in the Yanshanian movement. Of which the NW-trending structure was formed in first-stage Yanshanian and a series of SN-trending structure were formed in the second-stage Yanshanian. Finally, the sinistral strike-slipping happened in the Yanshanian movement. In some areas, there are some abnormal deformation such as rhombic-shaped fold superposition being controlled by border faults.2. The processes of both fold growth and formation show convergently-developed features at the conjunction point of structures or at the region of pre-existing structures strongly influencing later structures, based on the analysis of fold styles and patterns in the eastern and southeastern Sichuan Province. Moreover, the same phenomenon can be also found in the course of fault growth.3. Some new methods in this paper are proposed to distinguish the superposed structures and combined structure, including analysis fold’s axial line and joint system for classical and regional deformation in the Middle to Lower Yangzte block.4. The dynamic mechanism are discussed based on analysis of the structural geometry and kinematics. However , the collission of the Yangtze block with the Indochina block and the North China block resulted in the formation of Indosinian structures. In the later Triassic, intracontinental collission of the Yangtze block with the Cathaysian block produced the NE-SW-trending arc structures. The NE-trending structures maybe be related to the NW-directed subduction of the Izanaqi and Pacific plates under the Yangtze block. At last,the subduction of the Pacific plate to the Yangtze block changed toward NWW direction and produced the SN-trending structures.更多还原