Structural Characteristics And Evolution Of Shungengshan-Luoshan Nappe In Huainan

The Shungengshan-Luoshan nappe in Huainan is located in the southern margin of the North China plate,which formed the present tectonic style in the long-term geological evolution.The purpose of this paper is to enrich the study of nappe structure in Huainan area and to provide reference for resource exploration in Huainan area.For the purpose of providing guidance for coal mining and development,and providing theoretical basis for coal mine safety production,through field geological survey,structural statistics and evolution,micro-analysis and other methods,in this paper,it is explored in the geological structure type,geometric shape,structural evolution history and formation mechanism of the study area from the aspects of typical section characteristics,macro and micro geological structural characteristics,and dynamic characteristics.The conclusions are as follows:(1)The study area spreads in the E-W direction,mainly composed of the Shungengshan block and the Luoshan block,and is a "klippe" formed by the thrust nappe structure.The Shungengshan block mainly exposes the Cambrian and Ordovician strata,and the stratigraphic occurrence is inverted;the Luoshan block is mainly the Proterozoic and Archean strata,and the stratigraphic occurrence are normal.(2)The study area has extensively developed fault structures,and the Shungengshan fault controls the structural pattern of the entire area;the fold structures in the area are not large-scale,and mostly appear as small interlayer folds.The structure of the study area is linearly distributed in the E-W direction.The Shungengshan fault is the main structure that controls the entire area.It is a thrust fault.There are also several sets of N-S trending translational faults in the area.Rock slices show that the study area has experienced at least three tectonic movements with different directions and hydrothermal activity.(3)By restoring the paleo-tectonic stress field in the study area,it is concluded that the nappe in the study area has mainly experienced four phases of tectonic movement,namely:phase ? movement near the N-S direction,and phase ? near the NW-SE direction,phase ? movement in the NE-SW direction,and phase ?movement in the near E-W direction.(4)The Shungengshan-Luoshan nappe was formed during the Indosinian Movement.Under the N-S direction compressive stress in the study area,the strata inverted,and the Shungengshan fault formed,which then formed the Shungengshan nappe;in the early Yanshan Movement,the area was compressed from the NW-SE direction to the NWW-SEE direction,and the Precambrian strata of the Shungengshan nappe occurred twice,forming the Luoshan nappe.The structure of the Shungengshan-Luoshan nappe is preliminary formation;from the middle and late stages of the Yanshan Movement to the Himalayas Movement,the Shungengshan-Luoshan nappe was transformed by extensional movement and influenced by the sedimentation of the strata,and gradually developed into the present structural appearance.Figure[31]Table[8]Reference[83]...