Objective The uplift process and uplift mechanism of the Tibetan Plateau has been a research focus among geologists in recent years. This work put emphasis on the Cenozoic exhumation histories of the blocks bounded by...Objective The uplift process and uplift mechanism of the Tibetan Plateau has been a research focus among geologists in recent years. This work put emphasis on the Cenozoic exhumation histories of the blocks bounded by the major faults at the central segment of the Longmenshan thrust belt, and the vertical faulting history, including the starting time and the total vertical displacement, of the major faults. Then we quantitatively established a complete active process for the central segment of the Longmenshan thrust belt, combining with the previous geophysical data in the deep and geologcial data. This study is critical for deeply and completely understanding the Cenozoic uplift history of the Longmenshan, and also provides thermochronology constraints to the different models for the uplift of the eastern margin of the Tibetan Plateau.展开更多
Objective The occurrence of the devastating Wenchuan earthquake not only caused huge economic loss and deaths but also raised a question whether or not it would trigger any destructive earthquakes on its neighboring s...Objective The occurrence of the devastating Wenchuan earthquake not only caused huge economic loss and deaths but also raised a question whether or not it would trigger any destructive earthquakes on its neighboring segments in the Longmenshan Thrust Zone （LTZ） in the future.展开更多
In order to reveal the nature of the segmentation of Longmen Mountains Thrust Belt caused by the three nappes (Jiaoziding, Jiudingshan, and Baoxing Nappe), several methods are applied in this paper, including field in...In order to reveal the nature of the segmentation of Longmen Mountains Thrust Belt caused by the three nappes (Jiaoziding, Jiudingshan, and Baoxing Nappe), several methods are applied in this paper, including field investigation, seismic explanation and balanced crossed section, etc. Results of research reveal that nappes in Longmen Mountains vary in geometry, kinematics, and dynamics. Jiaoziding Nappe has generally behaved in a ductile manner, whereas Jiudingshan Nappe has been rigid, and the rheology of Baoxing Nappe has been intermediate between that of the other two nappes. The development of nappes has resulted in tectonic segmentation of Longmen Mountains: the main structural style of the northern segment is thrust faulting, with Jiaoziding Nappe representing a giant syncline. Given its ductility, it absorbed lots of stress, with the least amount of tectonic shortening in the SE part of the nappe. In the middle segment, the deformation is controlled by the rigid Jiudingshan Nappe, whose frontal area records lots of tectonic shortening. Deformation in the southern segment is intermediate in character between that of the other two segments, characterized by horizontal zonation, as demonstrated by fault development, and vertical stratification, which indicates that fault development was controlled by lithology.展开更多
The western segment of the East Kunlun Mountains is one of the poorly studied regions in northwestern China. Through a structural analysis of the typical sections, we have the following views: (1) There is a very well...The western segment of the East Kunlun Mountains is one of the poorly studied regions in northwestern China. Through a structural analysis of the typical sections, we have the following views: (1) There is a very well developed fault system in the western segment of the East Kunlun Mountains and thrust propagation, normal slip and decoupling are the chief deformation events in this area. (2) Although the thrusting started in the Late Carboniferous and Late Triassic-Early Jurassic, strong activity took place in the Miocene-Quaternary when the Kumkol basin was strongly downwarped. (3) The tectonic pattern of coexistence of N-directed thrust propagation and S-directed normal slip in this area is consistent with the general tectonic pattern of the northern Qinghai-Tibet plateau and also very similar to that of the Himalayan region on the southern margin of the Qinghai-Tibet plateau, but their directions between the thrust propagation are opposite and all the strong thrust propagations occurred from the Miocene-Pliocene to Quaternary, a period featuring strong collision between the Indian plate and the Eurasian plate and abrupt uplift of the Qinghai-Tibet plateau. This oppositely directed thrust propagation and normal slip reveal such kinematic characteristics as symmetric propagations of deep-seated materials towards the north and south beneath the Qinghai-Tibet plateau and gravitational sliding of superficial materials towards the interior of the plateau. Therefore, the establishment of the fault system in the study area may provide an approach to the study of deep processes of the northern Qinghai-Tibet plateau and the construction of a unified geodynamic model for the uplift of the Qinghai-Tibet plateau.展开更多
Field investigation and seismic section explanation showed that the Longmen Mountain Thrust Belt has obvious differential deformation： zonation, segmentation and stratification. Zonation means that, from NW to NE, th...Field investigation and seismic section explanation showed that the Longmen Mountain Thrust Belt has obvious differential deformation： zonation, segmentation and stratification. Zonation means that, from NW to NE, the Longmen Mountain Thrust Belt can be divided into the Songpan- Garz~ Tectonic Belt, ductile deformation belt, base involved thrust belt, frontal fold-thrust belt, and foreland depression. Segmentation means that it can be divided into five segments from north to south： the northern segment, the Anxian Transfer Zone, the center segment, the Guanxian Transfer Zone and the southern segment. Stratification means that the detachment layers partition the structural styles in profile. The detachment layers in the Longmen Mountain Thrust Belt can be classified into three categories： the deep-level detachment layers, including the crust-mantle system detachment layer, intracrustal detachment layer, and Presinian system basal detachment layer; the middle-level detachment layers, including Cambrian-Ordovician detachment layer, Silurian detachment layer, etc.; and shallow-level detachment layers, including Upper Triassic Xujiahe Formation detachment layer and the Jurassic detachment layers. The multi-level detachment layers have a very important effect on the shaping and evolution of Longmen Mountain Thrust Belt.展开更多
On August 2,a twin-segment solid rocket motor of the largest diameter,grain mass and thrust in China completed its ground test firing with success.The3 m solid motor was independently developed by the Academy of Aeros...On August 2,a twin-segment solid rocket motor of the largest diameter,grain mass and thrust in China completed its ground test firing with success.The3 m solid motor was independently developed by the Academy of Aerospace Solid Propulsion Technology（AASPT）under CASC.展开更多
基金supported by the National Natural Science Foundation of China(grant No.41302159)
文摘Objective The uplift process and uplift mechanism of the Tibetan Plateau has been a research focus among geologists in recent years. This work put emphasis on the Cenozoic exhumation histories of the blocks bounded by the major faults at the central segment of the Longmenshan thrust belt, and the vertical faulting history, including the starting time and the total vertical displacement, of the major faults. Then we quantitatively established a complete active process for the central segment of the Longmenshan thrust belt, combining with the previous geophysical data in the deep and geologcial data. This study is critical for deeply and completely understanding the Cenozoic uplift history of the Longmenshan, and also provides thermochronology constraints to the different models for the uplift of the eastern margin of the Tibetan Plateau.
基金jointly supported by the National Natural Science Foundation of China(grant No.41602206)the International Science&Technology Cooperation Program of China(grant No.2011DFG23400)
文摘Objective The occurrence of the devastating Wenchuan earthquake not only caused huge economic loss and deaths but also raised a question whether or not it would trigger any destructive earthquakes on its neighboring segments in the Longmenshan Thrust Zone （LTZ） in the future.
文摘In order to reveal the nature of the segmentation of Longmen Mountains Thrust Belt caused by the three nappes (Jiaoziding, Jiudingshan, and Baoxing Nappe), several methods are applied in this paper, including field investigation, seismic explanation and balanced crossed section, etc. Results of research reveal that nappes in Longmen Mountains vary in geometry, kinematics, and dynamics. Jiaoziding Nappe has generally behaved in a ductile manner, whereas Jiudingshan Nappe has been rigid, and the rheology of Baoxing Nappe has been intermediate between that of the other two nappes. The development of nappes has resulted in tectonic segmentation of Longmen Mountains: the main structural style of the northern segment is thrust faulting, with Jiaoziding Nappe representing a giant syncline. Given its ductility, it absorbed lots of stress, with the least amount of tectonic shortening in the SE part of the nappe. In the middle segment, the deformation is controlled by the rigid Jiudingshan Nappe, whose frontal area records lots of tectonic shortening. Deformation in the southern segment is intermediate in character between that of the other two segments, characterized by horizontal zonation, as demonstrated by fault development, and vertical stratification, which indicates that fault development was controlled by lithology.
文摘The western segment of the East Kunlun Mountains is one of the poorly studied regions in northwestern China. Through a structural analysis of the typical sections, we have the following views: (1) There is a very well developed fault system in the western segment of the East Kunlun Mountains and thrust propagation, normal slip and decoupling are the chief deformation events in this area. (2) Although the thrusting started in the Late Carboniferous and Late Triassic-Early Jurassic, strong activity took place in the Miocene-Quaternary when the Kumkol basin was strongly downwarped. (3) The tectonic pattern of coexistence of N-directed thrust propagation and S-directed normal slip in this area is consistent with the general tectonic pattern of the northern Qinghai-Tibet plateau and also very similar to that of the Himalayan region on the southern margin of the Qinghai-Tibet plateau, but their directions between the thrust propagation are opposite and all the strong thrust propagations occurred from the Miocene-Pliocene to Quaternary, a period featuring strong collision between the Indian plate and the Eurasian plate and abrupt uplift of the Qinghai-Tibet plateau. This oppositely directed thrust propagation and normal slip reveal such kinematic characteristics as symmetric propagations of deep-seated materials towards the north and south beneath the Qinghai-Tibet plateau and gravitational sliding of superficial materials towards the interior of the plateau. Therefore, the establishment of the fault system in the study area may provide an approach to the study of deep processes of the northern Qinghai-Tibet plateau and the construction of a unified geodynamic model for the uplift of the Qinghai-Tibet plateau.
基金support from:National Natural Science Foundation of China (Grant no.40672143,40472107,40172076)National Major Fundamental Research and Development Project (Grant no.2005CB422107,G1999043305)+1 种基金Development Foundation of Key Laboratory for Hydrocarbon Accumulation of Education Ministry (Grant no.2003-01)Project of Southern Exploration and Development Division Company,SINOPEC (2003-04).
文摘Field investigation and seismic section explanation showed that the Longmen Mountain Thrust Belt has obvious differential deformation： zonation, segmentation and stratification. Zonation means that, from NW to NE, the Longmen Mountain Thrust Belt can be divided into the Songpan- Garz~ Tectonic Belt, ductile deformation belt, base involved thrust belt, frontal fold-thrust belt, and foreland depression. Segmentation means that it can be divided into five segments from north to south： the northern segment, the Anxian Transfer Zone, the center segment, the Guanxian Transfer Zone and the southern segment. Stratification means that the detachment layers partition the structural styles in profile. The detachment layers in the Longmen Mountain Thrust Belt can be classified into three categories： the deep-level detachment layers, including the crust-mantle system detachment layer, intracrustal detachment layer, and Presinian system basal detachment layer; the middle-level detachment layers, including Cambrian-Ordovician detachment layer, Silurian detachment layer, etc.; and shallow-level detachment layers, including Upper Triassic Xujiahe Formation detachment layer and the Jurassic detachment layers. The multi-level detachment layers have a very important effect on the shaping and evolution of Longmen Mountain Thrust Belt.
文摘On August 2,a twin-segment solid rocket motor of the largest diameter,grain mass and thrust in China completed its ground test firing with success.The3 m solid motor was independently developed by the Academy of Aerospace Solid Propulsion Technology（AASPT）under CASC.
