Study On The Geometrical Characteristics,Kinematic Properties And Dynamic Creep Mechanism Of Faulted Structures In Langshan Area,Inner Mongolia Province

The Langshan Mountain area of Inner Mongolia is located in the northeast margin of the Alashan block,connected with the Central Asian orogenic belt in the north,and connected with the Ordos block(The North China Craton)in the east.It is separated from the North-easterly,left-sliding Bayanwula-Langshan Mountain fault,and is a transition area between the Alashan block and the North China Craton.The tectonic position is very important.Langshan mountain geological history and tectonic activity and the north of the central Asian orogenic belt,the east to the west of north China craton,the qilian orogenic belt and the tarim craton,tianshan orogenic belt,beishan orogenic belt and so on have the close relation,and tianshan tectonic belt,xing and the interaction between Siberian plate and north China plate craton in key areas,for a long time,a lot of research has been focused on the northeast,Inner Mongolia region in the eastern part of central Asian orogenic belt and the western tianshan mountains-beishan area,research on la shan in the central part of the plot is relatively small,especially in the northern margin of north China plate palaeo-ocean contentious issue of the closing time,The dynamic mechanism of the closure of the ancient ocean and the principal stress axial bearing caused by it are rarely mentioned.Combined with field investigation and measurement,this study on a large number of fault and fold form of geometry,kinematics,dynamics mechanism and characteristics of tectonic stress field of study,this paper use a shot plane projection method,find out the formation of tectonic stress field of orientation of principal stress axes,and tectonic evolution of this area are discussed in this paper.The fault structure in The Wolushan area of Inner Mongolia is very complex,and there are mainly north-south,east-west,nNE and NW trending fault structures.Through a lot of field observation and measurement,after the plane projection after statistical analysis that received at least two phase of the tectonic stress field in the study area,the first stage is in late Permian,as north China carat,leads to the north to the south,Siberia plate activity GuYaZhou ocean closed to form a collision collage movement produced nearly ns-trending horizontal compressional tectonic stress field,the principal compressive tectonic stress field of the principal stress axis sigma 1 to 9° north by east,north of pitching,pitching Angle of 11°.Under the action of this tectonic stress field,a set of rupture systems developed in The Wolf Mountain area,which were respectively manifested as compressional tectonic belts and thrust faults near east-west strike,left-trending strike-slip faults near NE strike,right-trending strike-slip faults near NW strike,and extensional faults near South-North strike.These early fault systems also restricted subsequent tectonic activity in the region.The second tectonic stress field is caused by the subduction of the Paleo-Pacific plate to the Asian continent since the Jurassic.The main compressive stress axis 1 of the tectonic stress field is 138°,and it plunges to the south east with a dip Angle of 19°.Under the influence of tectonic stress field,the early north-south fault changed from the original tensional fracture plane to the left strike-slip,the early east-west fault to the right strike-slip,the early NE left-lateral slip plane to the compressive plane and the axial direction of fold,and the early NW fault plane to the tensional fracture property.