Geological studies indicate that Qinghai\|Tibet plateau crust has shortened at least 2500km and the thickness was increased to 60～70km in the past 45Ma. Different researchers advocate different views to explain the s...Geological studies indicate that Qinghai\|Tibet plateau crust has shortened at least 2500km and the thickness was increased to 60～70km in the past 45Ma. Different researchers advocate different views to explain the shortening according to their studies.( Tapponnier,1977;Chang et al,1986;England et al,1986;Murphy,1997;Y.Pan,1999),however it is still unresolved on how much shortening in upper crustal especially in Qiangtang terrain.Qiangtang terrain is located in the center of Qinghai\|Tibet plateau, the tectonic deformation has been resulted from intracontinental convergence and collision of India plate with Eurasian plate.The deformation style of Qiangtang terrain shows east\|west\|trending folds and thrusts which formed in the shallow tectonic level during collisional\|intracontinental period. The folds type is characterized by nonpenetrative\|foliation parallel fold, the hinges have the same trend with the thrusts. These traits are favourable for restoring the balanced cross\|section and measuring the shortening. The balanced reconstruction is based on line balancing on three different stratigraphic sections (A,B and C)across the Northern Qiangtang basin in the area between 85°E and 87°E.The sections are all north\|south\|trending in accordance with the moving direction of thrusts.展开更多
文摘Geological studies indicate that Qinghai\|Tibet plateau crust has shortened at least 2500km and the thickness was increased to 60～70km in the past 45Ma. Different researchers advocate different views to explain the shortening according to their studies.( Tapponnier,1977;Chang et al,1986;England et al,1986;Murphy,1997;Y.Pan,1999),however it is still unresolved on how much shortening in upper crustal especially in Qiangtang terrain.Qiangtang terrain is located in the center of Qinghai\|Tibet plateau, the tectonic deformation has been resulted from intracontinental convergence and collision of India plate with Eurasian plate.The deformation style of Qiangtang terrain shows east\|west\|trending folds and thrusts which formed in the shallow tectonic level during collisional\|intracontinental period. The folds type is characterized by nonpenetrative\|foliation parallel fold, the hinges have the same trend with the thrusts. These traits are favourable for restoring the balanced cross\|section and measuring the shortening. The balanced reconstruction is based on line balancing on three different stratigraphic sections (A,B and C)across the Northern Qiangtang basin in the area between 85°E and 87°E.The sections are all north\|south\|trending in accordance with the moving direction of thrusts.
