Study On Geological Structure Characteristics And Evolution Process In Huainan Coal Field

The Huainan coalfield is located on the southern margin of the North China plate,and during the long-term geological evolution,complex tectonic systems were formed in the study area.Based on the collection and analysis of Huainan coalfield geological data,the properties,occurrence,shape and dynamics characteristics of the geological structure in the study area were analysied,and the formation mechanism and evolution process of the geological structure in this area were discussed,and obtained research result as follows:1.The folds are mainly developed in the central complex syncline tectonic zone,and most of them strikes near EW,their axial surface sloping S,and their hinge sloping E,they are gently solping domes and tectonic basins.2.Huainan coalfield is affected by multi-phase and multi-directional tectonic movements,and there are various fault structures with different properties,directions and shapes.3.large and medium-sized faults are concerned in the region,the tendency may be divided into five groups,which are mainly SSW orientation faults,followed by N,NWW,SEE,NNE orientation faults,and SSW,N,NWW,SEE orientation normal faults are also more developed,and SSW,NNE orientation reverse faults are also more developed.4.According to the mechanical properties of fault formation,the fault structures are divided into four types,that is,stretching type,extrusion type,strike slip type and inversion type,and the geometric shape,motion characteristics and formation process of the above types of faults are analyzed.5.The existing structural pattern in Huainan coalfield is the result of combined action from the Indosinian movement,Yanshan movement,Himalaya movement and neotectonic movement after coal strata formation,of which the Indosinian movement and Yanshan movement are the most critical two stages in the process of tectonic evolution,that is,Indosinian movement initially formed the near east-west fault distribution in Huainan coalfield,and the structural pattern of the hedging nappe structure and the compressional syncline;Yanshan movement has not only formed a structural pattern,but also formed a positive fault of NNE and NWW,and formed a staircase fault from the east to the West in the coal field.