Features Of Structure Deformation And Evolution In The North Siziwangqi, Inner Mongolia

Study on the regional tectonics of the northern margin of North China Craton isone of the important contents in the research of regional tectonics in China.Theboundary of the geosyncline and the platform of the northern margin of North ChinaCraton attracts a massive amount of geologists’attention.The tectonic evolution,fromthe Mesoproterozoic Era to the Paleozoic,has experienced strong tectonic deformationof multi period. Study of the accretion and tectonic evolution of northern margin ofNorth China Craton the collision zone will provide some foundation for the study ofXing’an Mongolian orogenic belt.It also plays a key role in the solution of manygeological problems of the northern margin of North China Craton.The paper is based on the guiding ideology of tectonics analysis.Throughgeological investigation, profile mapping work,to get a comprehensive collection oftectonic geometry and kinematics data.Through field geological work, establish thesequence of tectonic evolution.and finally get the following conclusion.1.The stratum of research area is Bayan Obo group which property indicates thenorthern margin of the North China Craton.This study considers Bayan Obo groupunderwent three stages of tectonic deformation from the Neoproterozoic to the MiddlePermian.The first phase of fold, mainly developes in the Bilute group andperformance as an early intraformational fold.It is formed in the period of theNeoproterozoic Jinning movement.The second phase of fold is mainly the regionalhomoclinal overturned fold.It formed in the Silurian during the late Caledonianmovement.The third phase of fold is the main one of the research area.It extendsalong the direction of EW.It formed in the period of early Middle Permian, lateHercynian movement.It starts at the same period with the Longtoushan trust nappestructure.2.A trust nappe structure is first found in the research area.It consists of thestratum of Bayan Obo group and early Permian volcanic rock and middle Permianigneous rock.The trust nappe structure was acted280~264Ma.It is the product of Platemarginal orogeny.It also means that the boundary of the northern margin of the North 3.China Craton goes through the research area.4.Through the partitioning of fold deformation period,and the magma andvolcano eruption event,I established the tectonic deformation sequence and clarifiedthe tectonic evolution history.