DEEP STRUCTURAL ANALYSIS IN CENTRAL ANHUI
Liu Deliang (Department of Earth and Space, Chinese University of Science and Technology, Hefei)Li Xiuxin(Headquarters for Petroleum Prospecting, Anhui Province)
By analysing the relations between the features of geophysical field and geologic body of the different levels, the evolution of deep structures may be explored. Based on the data computation of gravitational and magnetic fields, this paper discusses the problems of stratified block structure and slipping tectonics of the upper crust in central Anhui.The central Anhui is a transitional region between the three principal tectonic units of East China, of which the north belongs to the tectonic region of North China, the soutk to the Qinling-Dabie tectonic region and the east to the Yangtze tectonic region. The upper crust in this area may be divided into three basic structural strata and three corresponding main control structures. The lower structural stratum is 10000 m thick and the trend is mainly in SN direction; the middle one is 5000 m thick and mainly in EW direction; the upper one is 3000 m thick and in NNE direction.The structural strato-blocks limited by the boundary faults of the tectonic units and the faults between structural strata, including inner part of the structural strato-blocks and its bounds, have undergone a unified deformation related to each other. Both the thrust between the structural strata and the reversal of the upper boundary faults of the tectonic area are accompanied by nappe structure. The crust movement of this region, including the lower structural stratum of North China tectonic region underthrusting southwards, meanwhile the lower structural stratum of the Yangtze tectonic region upthrusting northwards, have pushed schist series of Qinling-Dabie tectonic region middle structural stratum. Thus a we-idged nappe was formed. A gravitation slip accompanied with pushing uplift has occurred.