Study On Cenozoic Tectonic Deformation Of The Hulesitai Region In The Western Yinshantectonic Zone

Inner Mongolia Hulesitai area is located in the northern margin of North China Craton,western margin of Yinshan inland deformation zone.The Stratum of the study area includes Zhaertai Group?Dahongshan Group ?Wudanggou Group?ChanghangouGroupand late Hercynian period magmatic rock.The different strata of the era recorded multiple deformation,there are two tectonic movementsin the study area.Early defomaionmodeinHulesitaiarea mainly includes:EW-trendingfaultand the fold formation of stratum.The Wujiahe area,in the east ofstudy area,the trend of theAgulugou Formaion is E-W.Thereis also a various of fold in the Agulugou Formaion.The Yihejiu area,in the west of study area,dveloped a large scale of A-fold,and it`s covered by Permian Dahongshan Formation by the angel unconformity.According to the deformation stratigraphic era and the synthesis of previous research results,it is inferred that the deformation occurred in the Devonian.The deformation may be affected by the Bainaimiao Island arc proliferation to the northern margin of North China or the closed of the Paleo-Asian Oceanic Sea.The late NE-SW tectonics include a series of NE-SW oriented thrust faults,such as Hashatumiao Fault?Wulanhuduge Fault?Harengetele Fault.The Hashatumiao fault is the Mesoproterozoic and the Permian intrusive rocks thrust upon the Jurassic Shigui Group from the NW to the SE.The Harengeteler fault is mainly characterized by the Lower Jurassic Wudanggou Formation thrust upon the Middle Jurassic Changhangou Formation from the NW to the SE.The latest strata involved in the late NW-SE deformation are the middle-lower Jurassic Shiguai Group,the study area lack of the Upper Jurassic Daqingshan Formation,In the northwest of the study area,theLower Cretaceous strata near level,not involved in fold deformation.So,the defomation may be limited to the middle-late Jurassic.The tectonic deformation may be related to the closure of the Mongolian-Okhotsk ocean,andthesouthward moving of the Siberian Block.