Lying at the junction of the Dabashan, Longmenshan and Qinling mountains, the Micangshan Orogenic Belt coupled with a basin is a duplex structure and back-thrust triangular belt with little horizontal displacement, sm...Lying at the junction of the Dabashan, Longmenshan and Qinling mountains, the Micangshan Orogenic Belt coupled with a basin is a duplex structure and back-thrust triangular belt with little horizontal displacement, small thrust faults and continuous sedimentary cover. On the basis of 3D seismic data, and through sedimentary and structural research, the Micangshan foreland can be divided into five subbelts, which from north to south are： basement thrust, frontal thrust, foreland depression-back-thrust triangle, foreland fold belt or anticline belt, and the Tongjiang Depression. Along the direction of strike from west to east, the arcuate structural belt of Micangshan can be divided into west, middle and east segments. During the collision between the Qinling and Yangtze plates, the Micangshan Orogenic Belt was subjected to the interaction of three rigid terranes： Bikou, Foping, and Fenghuangshan （a.k.a. Ziyang） terranes. The collision processes of rigid terranes controlled the structural development of the Micangshan foreland, which are： （a） the former collision between the Micangshan-Hannan and Bikou terranes forming the earlier rudiments of the structure; and （b） the later collision forming the main body of the structural belt. The formation processes of the Micangshan Orogenic Belt can be divided into four stages： （1） in the early stage of the Indosinian movement, the Micangshan-Hannan Rigid Terrane was jointed to the Qinling Plate by the clockwise subduction of the Yangtze Plate toward the Qinling Plate; （2） since the late Triassic, the earlier rudiments of the Tongnanba and Jiulongshan anticlines and corresponding syncline were formed by compression from different directions of the Bikou, Foping and Micangshan-Hannan terranes; （3） in the early stage of the Himalayan movement, the Micangshan-Hannan Terrane formed the Micangshan Nappe torwards the foreland basin and the compression stresses were mainly concentrated along both its flanks, whereas the Micangshan-Hannan Terrane wedged into the Qinling Orogenic Belt with force; （4） in the late stage of the Himalayan movement, the main collision of the Qinling Plate made the old basement rocks of the terrane uplift quickly, to form the Micangshan Orogenic Belt. The Micangshan foreland arcuate structure was formed due to the non-homogeneity of terrane movement.展开更多
Brittle structures in rock of different ages can be used to establish the tectonic evolution of an orogenic belt through paleostress calculations. Micangshan is located at the southern margin of the Qinling orogenic b...Brittle structures in rock of different ages can be used to establish the tectonic evolution of an orogenic belt through paleostress calculations. Micangshan is located at the southern margin of the Qinling orogenic belt, between the SE-trending Longmenshan fold-and-thrust belt and the arcuate Dabashan thrust-and-fold belt. Structural observations revealed that the dominant structures are reverse and strike-slip faults and folds with E-W and NE-SE trends. To increase knowledge of the tectonic evolution of the Micangshan anticlinorium, faults, joints, veins, and folds were measured at more than eighty sites. On the basis of structural analysis, it emerged that the multiphase paleostress fields became established after the oblique collision between the North and South China plates. The earliest stress field with N-S compression was established during the Micangshan uplift associated with the E-W trending faults and folds. Subsequently, a N-S extension occurred when the Qinling orogenic belt collapsed. Then NW-SE compression developed, with NE trending faults and folds forming in relation to Longmenshan thrusting toward southwest on the eastern margin of the Tibetan plateau. With the development of the arcuate Dabashan orogenic belt, the compression stress orientation of the Micangshan anticlinorium altered from NE-SW to E-W.展开更多
The Micangshan Forest Park is located in the northeast edge of the Sichuan Basin. The wild animals and plants resources are rich and the ecosystem is integrity. There are well-preserved areas of native biological comm...The Micangshan Forest Park is located in the northeast edge of the Sichuan Basin. The wild animals and plants resources are rich and the ecosystem is integrity. There are well-preserved areas of native biological communities. Its strip and the region decided that on the one hand biological diversity is rich; on the other hand, there is its unique ecological fragility. Once it is destroyed, it would be very difficult to restore. In order to protect the ecological environment of wild animal and plant habitats and wild animal and plant resources, this paper uses quadrat survey procedure to carry on the investigation. In the Micangshan Forest Park's typical land sector the author establishes the sample area of 20 m×20 m to invest the tree layer of plant species and builds five 2 m×2 m the small quadrats along the type place's diagonal line machinery to invest bush level and the field layer floristic component. Again according to the Micangshan Forest Park's terrain, the vegetation and the difference humanity interference condition, the autor builds the different quantities separately the line transect to invest the animal type. This article through to eastern Sichuan Province north the Micangshan forest park biodiversity resources investigation, has analyzed the biodiversity protection work present situation and the existence question, and put forward the proposal to the next protection work.展开更多
基金These research results are part of a key project carried out in 2005-2007 and financially supported by the Natural Science Foundation of China (No.40472110).
文摘Lying at the junction of the Dabashan, Longmenshan and Qinling mountains, the Micangshan Orogenic Belt coupled with a basin is a duplex structure and back-thrust triangular belt with little horizontal displacement, small thrust faults and continuous sedimentary cover. On the basis of 3D seismic data, and through sedimentary and structural research, the Micangshan foreland can be divided into five subbelts, which from north to south are： basement thrust, frontal thrust, foreland depression-back-thrust triangle, foreland fold belt or anticline belt, and the Tongjiang Depression. Along the direction of strike from west to east, the arcuate structural belt of Micangshan can be divided into west, middle and east segments. During the collision between the Qinling and Yangtze plates, the Micangshan Orogenic Belt was subjected to the interaction of three rigid terranes： Bikou, Foping, and Fenghuangshan （a.k.a. Ziyang） terranes. The collision processes of rigid terranes controlled the structural development of the Micangshan foreland, which are： （a） the former collision between the Micangshan-Hannan and Bikou terranes forming the earlier rudiments of the structure; and （b） the later collision forming the main body of the structural belt. The formation processes of the Micangshan Orogenic Belt can be divided into four stages： （1） in the early stage of the Indosinian movement, the Micangshan-Hannan Rigid Terrane was jointed to the Qinling Plate by the clockwise subduction of the Yangtze Plate toward the Qinling Plate; （2） since the late Triassic, the earlier rudiments of the Tongnanba and Jiulongshan anticlines and corresponding syncline were formed by compression from different directions of the Bikou, Foping and Micangshan-Hannan terranes; （3） in the early stage of the Himalayan movement, the Micangshan-Hannan Terrane formed the Micangshan Nappe torwards the foreland basin and the compression stresses were mainly concentrated along both its flanks, whereas the Micangshan-Hannan Terrane wedged into the Qinling Orogenic Belt with force; （4） in the late stage of the Himalayan movement, the main collision of the Qinling Plate made the old basement rocks of the terrane uplift quickly, to form the Micangshan Orogenic Belt. The Micangshan foreland arcuate structure was formed due to the non-homogeneity of terrane movement.
基金the China Geological Survey Program (Grant No.1212011220748 and 1212011220761)the Project of the National Natural Science Foudation of China (Grant No.40802049)
文摘Brittle structures in rock of different ages can be used to establish the tectonic evolution of an orogenic belt through paleostress calculations. Micangshan is located at the southern margin of the Qinling orogenic belt, between the SE-trending Longmenshan fold-and-thrust belt and the arcuate Dabashan thrust-and-fold belt. Structural observations revealed that the dominant structures are reverse and strike-slip faults and folds with E-W and NE-SE trends. To increase knowledge of the tectonic evolution of the Micangshan anticlinorium, faults, joints, veins, and folds were measured at more than eighty sites. On the basis of structural analysis, it emerged that the multiphase paleostress fields became established after the oblique collision between the North and South China plates. The earliest stress field with N-S compression was established during the Micangshan uplift associated with the E-W trending faults and folds. Subsequently, a N-S extension occurred when the Qinling orogenic belt collapsed. Then NW-SE compression developed, with NE trending faults and folds forming in relation to Longmenshan thrusting toward southwest on the eastern margin of the Tibetan plateau. With the development of the arcuate Dabashan orogenic belt, the compression stress orientation of the Micangshan anticlinorium altered from NE-SW to E-W.
文摘The Micangshan Forest Park is located in the northeast edge of the Sichuan Basin. The wild animals and plants resources are rich and the ecosystem is integrity. There are well-preserved areas of native biological communities. Its strip and the region decided that on the one hand biological diversity is rich; on the other hand, there is its unique ecological fragility. Once it is destroyed, it would be very difficult to restore. In order to protect the ecological environment of wild animal and plant habitats and wild animal and plant resources, this paper uses quadrat survey procedure to carry on the investigation. In the Micangshan Forest Park's typical land sector the author establishes the sample area of 20 m×20 m to invest the tree layer of plant species and builds five 2 m×2 m the small quadrats along the type place's diagonal line machinery to invest bush level and the field layer floristic component. Again according to the Micangshan Forest Park's terrain, the vegetation and the difference humanity interference condition, the autor builds the different quantities separately the line transect to invest the animal type. This article through to eastern Sichuan Province north the Micangshan forest park biodiversity resources investigation, has analyzed the biodiversity protection work present situation and the existence question, and put forward the proposal to the next protection work.
