Tectonic Geological Characteristics And Evolution Of Dejiang Area,Guizhou Province

The study area is located in the southeast margin of the Yangtze platform.the tectonic evolution of the Paleozoic-Cenozoic era is unique,and is closely related to the expansion,subduction and collision of the Yangtze block and the Huaxia landmass.The upper Yangtze and the southeast margin are the key areas reflecting the evolution of the south China tectonic-basin,and also the key oil and gas exploration areas in the lower Paleozoic in south China.Therefore,it has important geological significance to study the stratigraphic characteristics and tectonic deformation characteristics of the main tectonic rocks in the area and the tectonic relationship with the formation of the southeast margin of the Yangtze platform.Based on the latest research results and research progress of Dejiang and its adjacent areas in Guizhou province,based on sedimentology and tectonic geology,the structure and evolution process of Dejiang area in Guizhou province are clarified,and the structural deformation characteristics of Dejiang area in Guizhou province are studied comprehensively through the analysis of structural geometry,kinematics characteristics and regional tectonic setting.Based on the systematic review of previous research achievements and field investigation analysis and indoor comprehensive sorting,the following points are obtained:(1)Through the analysis of formation material composition,stratigraphic sequence,structural characteristics and formation environment of various strata,the formation and evolution of the region and lithofacies palaeogeography,especially the material composition and the representative geological events of the upper Ordovician strata,the parallel unconformity contact relationship between the Permian strata and the underlying strata,and their indicative significance are deeply studied.(2)The basic structure pattern of the research area is established,the geometry characteristics and deformation characteristics of the geological structure in the area are preliminarily recognized,and the structure of the key section is analyzed.According to the structural deformation scale,strength and distribution scale,deformation geometry and other characteristics,with f1 and F2 fracture as the boundary,the research regionalization is divided into two types of deformation zone and three deformation zones.(3)According to the exposed strata and deformation characteristics of the research area and adjacent area,the kinematics and dynamics characteristics of the different tectonic cycles are analyzed.It is believed that under the action of Yanshanian tectonic force eastward,the deformation of the uplifted basement with rigid property is relatively stable(tough),so the overburden deformation(amount)is relatively weak,and the cover relative plasticity(weak)on both sides of rigid basement is formed under the influence of regional tectonic force and boundary fault activity.