The Tectonic Characteristics Of Typical Slope Zones In Jizhong Depression

Slope zone is transitioned from the deep sag zone to the in dustpan-like sag of continental rift basin.It is an overlapping and erosion monoclonal zone,connected to the surrounding salient and subsag by a slope form.It has important meaning for deepen researching the basin mechanism and tectonic evolution.At the same time,it provides theory direction in petroleum prospecting.This paper studies geometry,kinematics and dynamics of slope zones in Jizhong depression as research objects by analyzing the areal geology background,three dimensional seismic data,structure superface data,logging data and so on.According to the geology background,the characteristics of three dimensional seismic data,the planar and profile characteristics of faults in every slope,the type of slope zones in Jizhong depression are redefined.The formation and evolutionary process are restored and the distribution of faults are figured out by calculating extension amount,extension proportion,extension rate and using the method of balanced cross section.Finally,the mechanism and the difference are made definite with the deep tectonic background of Jizhong depression and the combination of structural physical modeling.The conclusions can be stated as follows: The typical slope zones in Jizhong depression include Wen'an slope,Lixian slope and Shulu West slope.Among them,Wen'an slope is a wide-gentle sedimentary slope,Lixian slope is a platform sedimentary slope,Shulu West slope is a narrow steep sedimentary-tectonic complex slope.Because of the influencing factors,such as differences in area stretching and construction of sag,ancient basement tectonics transformation,NE – NNE trending fault zones are the majority in the three slopes.The fault zone has large-scale,long development time and controls the deposition of Paleogene strata.At the same time,the three slopes develop NW or EW faults.These faults are mainly to regulatory effection.The formation and evolutionary process of each period are restored,every slope zone developed from the Cenozoic.The vigorous development of Wen'an slope took place in Es3-Es2,Lixian slope took place in Es1 and Shulu West slope took place in Es1.The deep tectonic background of Jizhong depression and structural physical modeling results show that the boundary faults and some second-grade faults are the main factor of the slope zone formation,basement structure and the development of sag play a key role in the formation of slope zone.