| The North China Craton is one of the oldest craton in the world,a large number of ductile shear zones are developed in the northern margin.These ductile shear zones indicate very important geological tectonic evolution information,so the study of these ductile shear zones can reveal the Proterozoic tectonic changes in the northern margin of the North China Craton,and provide some bases for the study of the North China Craton's participation in the reconstruction and disintegration of the Columbian Supercontinent.In this paper,a number of ductile shear structures have been discovered in the north margin of North China Craton in Siziwangqi area of Inner Mongolia.According to its distribution location and spatial distribution characteristics,it is mainly divided into three ductile shear zones.The deformation characteristics and deformation time of three ductile shear zones are discussed through field observation and indoor testing,and the Proterozoic tectonic movement in the north margin of North China Craton indicated by them is discussed.In this paper,research has shown that the ductile shear zone of Xiaojinggou is mainly ductile deformation under the background of the north-south extensional structure,deformation temperature is about 450550?,the differential stress value is about22.53 Mpa,strain rate is about 2.632.63×10-12 s-1,and its deformation time is about 1.86Ga,all of them indicate the extensional structure of late Paleoproterozoic and the stretch began shortly after it was judged that the Columbian Supercontinent had come together;The ductile shear zone of ear camp is judged to be the tectonic background of nearly north-south extension the deformation temperature is about 500550?,the differential stress is about 13.97 Mpa,the strain rate is less than 7.66×10-13 s-1,similar to the regional strain rate,and the deformation age is about1.80Ga.All of them indicate the extensional structure was developed in the same time as the Bayan obo rift zone in Mesoproterozoic.The deformation of the ductile shear zone of kundulun is the background of the NE-SW extensional structure,the deformation temperature is about550600?,the differential stress is about 20.86mpa,the strain rate is between3.29×10-11 s-11 and 1.68×10-12 s-1,the deformation rate is fast,and the ductile deformation time is between 1.71.6Ga,These indicate the continuous stretching movement of the Colombian Supercontinent after the initial extensional structure. |
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