乌拉尔造山带构造特征与演化历史OA

The Uralian orogenic belt records the multi-stage tectonic evolution of the arc-basin system along the western margin of the Proto-Tethys Ocean(Paleo-Asian Ocean),serving as a key area for deciphering the mechanisms of ocean-continent transformation and continental accretion.Based on plate tectonic theory and integrated with regional geological data and structural analysis,this study proposes a new tectonic subdivision scheme and evolutionary model to elucidate the structural characteristics and evolutionary history of the Uralian orogen.The research results indicate that:(1)The Uralian orogenic belt can be divided into seven major tectonic units:the Pre-Uralian foredeep,West Uralian thrust-nappe belt,Central Uralian basement uplift,Uralian accretionary complex belt,Tagil-Magnitogorsk multi-stage island arc belt,East Uralian granitic belt,and Trans-Uralian zone,exhibiting a westward-to-eastward progressive accretion polarity.(2)The tectonic evolution of the Uralian orogen is divided into six stages:continental rifting from the mid-Neoproterozoic(Riphean)to late Neoproterozoic(Vendian);the Paleo-Uralian Orogeny in the latest Neoproterozoic(Late Vendian);back-arc basin expansion from the Cambrian to Early Carboniferous;closure of the Uralian arc-basin system during the Carboniferous;the Uralian orogeny in the Middle to Late Permian;and intracontinental orogeny from the Mesozoic to Cenozoic.(3)The spatiotemporal differentiation of five arc-basin systems,including Tagil(sialic-basement)and Magnitogorsk(sima-basement),and the subduction-collision mechanisms controlling the multi-stage magmatic responses along the East Uralian granitic belt are revealed.(4)The Late Paleozoic subduction rollback-controlled rifting in the Caspian back-arc basin and the uplift-related molasse sedimentation in the orogenic belt constitute a coupled basin-orogen system.These findings provide new tectonic constraints for understanding the Uralian orogenic processes and the distribution of hydrocarbon resources in Central Asia.