孔南地区中古生界构造特征及其演化

发布时间：2018-05-12 23:37

本文选题：孔南地区 + 中古生界　；参考：《长江大学》2015年硕士论文

【摘要】：本文充分利用三维地震资料,结合钻井、测井解释成果,以构造几何学、地球运动学、动力学等理论观点为指导,运用平衡剖面技术恢复研究区构造演化过程,系统详细解析孔南地区中、古生界逆冲推覆带结构、断裂构造特征、各段典型构造样式及其构造演化与形成机制。在中古生界叠置盆地的构造解析研究中,在过井剖面及网格状地震-地质大剖面的综合解释的基础上,精细解释分析主要构造界面以及不同深度构造图,揭示了中、古生界叠置盆地构造性质、类型、样式的主要特征,共划分出挤压作用、伸展作用、剪切作用、反转作用相关的四种构造类型和十三种基本的构造样式；总结了中古生界逆冲推覆带各段五种典型构造样式；明确了推覆带与乌马营背斜、王官屯潜山等构造之问的相互关系。具体而言,推覆带可分为四段,南段以逆掩推覆为主,中南段以仰冲后展式断展推覆为主,中北段以仰冲前展式断展推覆为主,北段以逆冲推覆与叠瓦背冲交替为主。工区印支期总体构造特征为宽缓背向斜,燕山期具深层叠瓦冲断厚皮构造与浅层滑脱推覆薄皮构造纵向双层变形结构。中古生界具下古生界由南向北高角度远间距叠瓦逆冲拆离夹持背向斜特征,为基底卷入型构造；上古生界-中生界自北西西向南东方向逆冲推覆,形成盖层滑脱型构造。滑脱面为石炭系煤系地层与中奥陶统底部下马家沟组泥页岩层段。新生界构造负反转滑覆断裂与左旋剪切张扭构造对中古生界挤压构造具有改造作用。在对工区构造形成期次和主要构造形成机制的探讨研究中,取得以下几点认识：(1)本论文首次提出转换带之间,还存在四组北西向展布的张扭剪切带,表现为喜马拉雅早期左旋扭动性质,与郯庐断层右行走滑有关。(2)工区中古生界可概括为五大构造演化期次,分别为稳定地台期、宽缓背向斜产生期、盖层滑脱推覆期、张扭剪切改造期、断陷-拗陷沉降改造期。其中乌马营背斜、王官屯背斜主要形成于印支期,为板缘造山板内递进轻微变形结果,燕山期-喜山期构造运动对背斜构造进行了改造：徐黑潜山、王官屯潜山印支期为背斜一部分,喜山期构造负反转断裂切割为断块潜山。(3)上古生界-中生界逆冲推覆带主要产生于燕山陆内造山期,逆冲推覆带各段典型构造样式分布特征与逆冲推覆体发育所处特定构造部位相关。(4)研究区古背斜与推覆体上发育的前新生界重要角度不整合面为印支、燕山两期多幕剥蚀削截的结果。上、下正负向盆地构造以不整合面为界表现为镜像对应叠置关系。
[Abstract]:In this paper, we make full use of 3D seismic data, combined with drilling and logging interpretation results, based on structural geometry, geo-kinematics, dynamics and other theoretical points of view, using balanced section technology to restore the tectonic evolution process in the studied area. The structure of Paleozoic thrust-nappe belt, the characteristics of fault structure, the typical structural styles of each segment and their tectonic evolution and formation mechanism in Gongnan area are systematically analyzed in detail. In the structural analysis of the Middle Paleozoic superimposed basins, on the basis of the comprehensive interpretation of the cross well section and the grid seismo-geological section, the main structural interfaces and the structural maps of different depths are analyzed in detail. The main characteristics of the Paleozoic superimposed basins are the characteristics of tectonic properties, types and styles, which are divided into four tectonic types related to compressional, extensional, shearing and inversion processes and thirteen basic structural styles. Five typical structural styles of the Middle Paleozoic thrust nappe belt are summarized, and the interrelation between the nappe belt and the structures of the Wumaying anticline and the buried hill of Wangguantun are clarified. Specifically, the nappe belt can be divided into four sections, the south segment is mainly overthrust, the central and southern segment is dominated by the upside-thrust extended fault extension nappe, the central northern segment is dominated by the upper-thrust forward extension fault extension nappe, and the northern segment is dominated by the replacement of thrust nappe and brush-back thrust. The general structural characteristics of the Indosinian period in the working area are wide and slow anticlinal, and the Yanshanian period is characterized by deep imbricate thrusting thick crust structure and shallow slippage nappe structure with longitudinal double layer deformation structure. The Middle Paleozoic has the characteristics of the lower Paleozoic from the south to the north, and the upper Paleozoic and Mesozoic are thrust and nappe from NW to E, forming the tectonics of caprock detachment. The detachment surface is the Carboniferous coal series strata and the lower Majiagou formation shale formation at the bottom of the Middle Ordovician. The negative reverse slip fault and the left lateral shear tensional structure of the Cenozoic structure have the function of reforming the Middle Paleozoic compressional structure. In the study of the tectonic formation stages and the main tectonic formation mechanisms in the working area, the following points have been obtained: (1) in this paper, it is the first time that there are four groups of tensional shear belts distributed in the NW direction between the transition zones. The middle Paleozoic in the Tan-Lu fault right strike-slip area can be summed up as five tectonic evolution stages, namely, stable platform stage, wide and slow anticline generation period, caprock detachment and nappe stage, respectively, in the early Himalayan period, which is related to the right strike-slip of the Tanlu fault. The stage of shearing transformation of tensioning and torsion, the period of subsidence reformation of fault depression and depression. Among them, Wumaying anticline and Wangguantun anticline mainly formed in the Indosinian period, resulting in slight deformation in the plate margin orogenic plate. The tectonic movement of Yanshanian to Himalayan epoch reformed the anticline structure: Xu Kuroc buried hill, The Indosinian epoch of Wangguantun buried hill is part of the anticline, and the negative inversion fault of the Himalayan period is cut into the buried hill of fault block. 3) the Upper Paleozoic Mesozoic thrust nappe mainly occurred during the Yanshanian intracontinental orogenic period. The distribution characteristics of typical tectonic styles in each segment of the thrust nappe belt are related to the specific tectonic position in which the thrust nappe develops.) the important angle unconformity surface of the Paleo-anticline and nappe developed on the paleo-anticline and nappe is the Indosinian. The results of two episodes of multi-act denudation in Yanshan. In the upper and lower positive and negative basins, the boundary of the unconformities is mirrored and superimposed.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P548

【参考文献】