In the Langshan region, northwestern China, marked multi-stage intraplate deformation events have occurred since the Mesozoic, including（1） northeast-striking ductile left-lateral strike slip during the Middle-Late ...In the Langshan region, northwestern China, marked multi-stage intraplate deformation events have occurred since the Mesozoic, including（1） northeast-striking ductile left-lateral strike slip during the Middle-Late Triassic, which is closely related to the collision between the North China and the Yangtze plates;（2） top-to-the-southeast thrust with northwest-southeast trending maximum compression during the Late Jurassic;（3） nearly eastward detachment during the Early Cretaceous;（4） top-to-the-northwest thrust with northwest-southeast trending maximum compression during the Late Cretaceous and Early Cenozoic;（5） northeast-striking brittle left-lateral strike slip with nearly north-south trending maximum compression; and（6） northwest-southeast extension during the Middle-Late Cenozoic. All these deformation events belong to the intraplate deformation across the entire Central Asian region and respond to the tectonic events along the plate boundaries or deep tectonics. The structures developed in early events in the crust were the most important factors controlling the later deformation styles, and few new structures have later developed. Based on previous research and our results, the paleostress inversion in the Langshan region shows that the Mesozoic intraplate deformations in the study region mainly resulted from the tectonic events from the Paleo-Pacific region and have no or a weak relation to the Tethys region. During the Late Jurassic, the maximum compression from the Mongolia-Okhotsk region cannot be excluded. The Langshan region is the bridge between southern Mongolia and the western Ordos tectonic belt and is thus important to understand the nature and relationship between both regions.展开更多
The Xining Basin is located in the northeastern Qinghai-Tibetan Plateau, and its continuous Cenozoic strata record the entire uplift and outgrowth history of the Tibetan Plateau during the Cenozoic. The newly obtained...The Xining Basin is located in the northeastern Qinghai-Tibetan Plateau, and its continuous Cenozoic strata record the entire uplift and outgrowth history of the Tibetan Plateau during the Cenozoic. The newly obtained apatite fission track data presented here shows that the Xining Basin and two marginal mountain ranges have experienced multiphase rapid cooling since the Jurassic, as follows. In the Middle-Late Jurassic, the rapid exhumation of the former Xining Basin resulted from collision between the Qiangtang Block and the Tarim Block. During the Early-Late Cretaceous, the former Xining Basin underwent a tectonic event due to marginal compression, causing the angular unconformity between the Upper and Lower Cretaceous. In the Late Cretaceous to the Early Cenozoic, collision between the Qiangtang Block and the Lhasa Block may have resulted in the rapid exhumation of the Xining Basin and the Lajishan to the south. In the Early Cenozoic （ca. 50-30 Ma）, collision between the Indian and Eurasia plates affected the region that corresponds to the present northeastern Qinghai-Tibetan Plateau. During this period, the central Qilian Block rotated clockwise by approximately 24° to form a wedge-shaped basin （i.e., the Xining Basin） opening to the west. During ca. 17-8 Ma, the entire northeastern Qinghai-Tibetan Plateau underwent dramatic deformation, and the Lajishan uplifted rapidly owing to the northward compression of the Guide Basin from the south. A marked change in subsidence occurred in the Xining Basin during this period, when the basin was tectonically inverted.展开更多
基金funded by the National Science Foundation of China (Nos. 41172198, 40702032)China Geological Survey Project (Nos. 12120113096400, 1212011121064)
文摘In the Langshan region, northwestern China, marked multi-stage intraplate deformation events have occurred since the Mesozoic, including（1） northeast-striking ductile left-lateral strike slip during the Middle-Late Triassic, which is closely related to the collision between the North China and the Yangtze plates;（2） top-to-the-southeast thrust with northwest-southeast trending maximum compression during the Late Jurassic;（3） nearly eastward detachment during the Early Cretaceous;（4） top-to-the-northwest thrust with northwest-southeast trending maximum compression during the Late Cretaceous and Early Cenozoic;（5） northeast-striking brittle left-lateral strike slip with nearly north-south trending maximum compression; and（6） northwest-southeast extension during the Middle-Late Cenozoic. All these deformation events belong to the intraplate deformation across the entire Central Asian region and respond to the tectonic events along the plate boundaries or deep tectonics. The structures developed in early events in the crust were the most important factors controlling the later deformation styles, and few new structures have later developed. Based on previous research and our results, the paleostress inversion in the Langshan region shows that the Mesozoic intraplate deformations in the study region mainly resulted from the tectonic events from the Paleo-Pacific region and have no or a weak relation to the Tethys region. During the Late Jurassic, the maximum compression from the Mongolia-Okhotsk region cannot be excluded. The Langshan region is the bridge between southern Mongolia and the western Ordos tectonic belt and is thus important to understand the nature and relationship between both regions.
基金granted by the China Geological Survey Project("Study on the neotectonics of China and its relationship with the earthquake")the Scientific Special Projects of Institute of Geology,CAGS(No.J1121)
文摘The Xining Basin is located in the northeastern Qinghai-Tibetan Plateau, and its continuous Cenozoic strata record the entire uplift and outgrowth history of the Tibetan Plateau during the Cenozoic. The newly obtained apatite fission track data presented here shows that the Xining Basin and two marginal mountain ranges have experienced multiphase rapid cooling since the Jurassic, as follows. In the Middle-Late Jurassic, the rapid exhumation of the former Xining Basin resulted from collision between the Qiangtang Block and the Tarim Block. During the Early-Late Cretaceous, the former Xining Basin underwent a tectonic event due to marginal compression, causing the angular unconformity between the Upper and Lower Cretaceous. In the Late Cretaceous to the Early Cenozoic, collision between the Qiangtang Block and the Lhasa Block may have resulted in the rapid exhumation of the Xining Basin and the Lajishan to the south. In the Early Cenozoic （ca. 50-30 Ma）, collision between the Indian and Eurasia plates affected the region that corresponds to the present northeastern Qinghai-Tibetan Plateau. During this period, the central Qilian Block rotated clockwise by approximately 24° to form a wedge-shaped basin （i.e., the Xining Basin） opening to the west. During ca. 17-8 Ma, the entire northeastern Qinghai-Tibetan Plateau underwent dramatic deformation, and the Lajishan uplifted rapidly owing to the northward compression of the Guide Basin from the south. A marked change in subsidence occurred in the Xining Basin during this period, when the basin was tectonically inverted.
