Block faults, as the -dominant tectonic framwork of western Shandong, were formed by the linked extensional fault system through two extensional movements during the Meso-Cenozoic. Both of the extensional movements ex...Block faults, as the -dominant tectonic framwork of western Shandong, were formed by the linked extensional fault system through two extensional movements during the Meso-Cenozoic. Both of the extensional movements experienced the same evloutional process: first, the upper crust was pulled apart to form faults; then the Tai-Lu-Yi (Taishan-Lushan-Yishan) fault block occurring in the footwall of the extensional fault was uplifted, which induced the shallow-level detachment movement along the early Precambrian and Palaeozoic unconformity; the ' branching' fault in the upper part of the deep-level detachment layer propagated. As the shallow detachment moved towards the north and the deep one towards the south, the Tai-Lu-Yi fault block acted as the common footwall of both the southern and northern detachment systems. The Tai-Lu-Yi fault block rebounded and uplifted as the overlying material was pulled apart to cause an unloading. Sialic material of the mid-crust below the deep detachment flowed to and accumulated in the free space below the rebounding uplifted body and thickened the body; whereas the mid-crust thinned under the graben systems. The rebounding uplifted body cooled, and then the graben system was occluded, which resulted in the crust-mantle isostatic adjustment and asthenospheric convection. As a result of the two extensional movements, the uplifted central Shandong block with the Tai-Lu-Yi area as the core stands highly above the surrounding plain characterized by graben systems. The present Mount Taishan forms the climax of the uplift.展开更多
The paper focuses on the characteristics of faulting and magmatism of the Okinawa Trough and the relation between them. En-echelon grabens are ranked oblique to the continental shelf edge uplift, and the Longwang upli...The paper focuses on the characteristics of faulting and magmatism of the Okinawa Trough and the relation between them. En-echelon grabens are ranked oblique to the continental shelf edge uplift, and the Longwang uplift, the rifting block ridge in the northern segment and the ＂Mianhua uplift＂ in the southern segment have possibly preserved characteristics of volcanism and magmatism occurring with those rifting phases. The clockwise rotation of the southern Ryukyu Islands, driven by collision between Luzon and Taiwan, has played a key role in the crustal oceanization, enhancing the crustal extension of the southern segment and inducing volcanic magmatism in those grabens, among which the Yaeyama graben is a typical example of the presence of oceanic crust. Faulting and magmatism were mainly migrating towards the island arc asymmetrically. The crustal oceanization of the Okinawa Trough is difficultly interpreted by the linear magnetic anomaly model, which is fit for the symmetric spreading of the mid-oceanic ridges.展开更多
The analysis of Earth’s crust movement vertical velocities was made both for separate regions, and averaged on regions. As input data coordinates and velocities of earth crust points, obtained in International Coordi...The analysis of Earth’s crust movement vertical velocities was made both for separate regions, and averaged on regions. As input data coordinates and velocities of earth crust points, obtained in International Coordinate Systems ITRF2000, ITRF2005,ITRF2008 on the base of processing radio interferometric(VLBI), laser(SLR), Doppler(DORIS) and GPS observations was used. For the purpose of global analysis all input velocity values were averaged in the x trapezoids. For filling trapezoids the spherical function expansion to N=36 was made. Expansion harmonic coefficients allowed determine the global characteristics of earth crust movements both for all Earth, and for separate hemispheres, polar and equatorial regions, continents and oceans. It appears, that polar regions were risen, and equatorial ones were lowered, that can indicate the modern Earth oblateness reduction. The constructed maps of vertical velocities were compared with obtained by us map of earth crust strain distribution. It is appeared, that regions of modern earth surface rising(Fennoscandia, Canada, Antarctica) coincide with regions of vertical extension strain, and the lowering regions-with compression regions. Simultaneously with the determination of harmonious coefficients the mean-square error of approximation for expansion of power n=1 N and power dispersion were determined. Whereas the results converge badly and dispersion increased with the n grows, hence we can concludes, that vertical movements do not characterized global earth crust movement and denotes the unrelated character of these movement. Seemingly, the main cause of such movement origin is the local seismic events(earthquake, volcanic eruption and so on). It confirms by our conclusions about correspondence of vertical strain maximal gradient(and therefore vertical velocities) map of the earthquake distribution. In work the detailed analysis of obtained results for separate Earth’s regions was made.展开更多
文摘Block faults, as the -dominant tectonic framwork of western Shandong, were formed by the linked extensional fault system through two extensional movements during the Meso-Cenozoic. Both of the extensional movements experienced the same evloutional process: first, the upper crust was pulled apart to form faults; then the Tai-Lu-Yi (Taishan-Lushan-Yishan) fault block occurring in the footwall of the extensional fault was uplifted, which induced the shallow-level detachment movement along the early Precambrian and Palaeozoic unconformity; the ' branching' fault in the upper part of the deep-level detachment layer propagated. As the shallow detachment moved towards the north and the deep one towards the south, the Tai-Lu-Yi fault block acted as the common footwall of both the southern and northern detachment systems. The Tai-Lu-Yi fault block rebounded and uplifted as the overlying material was pulled apart to cause an unloading. Sialic material of the mid-crust below the deep detachment flowed to and accumulated in the free space below the rebounding uplifted body and thickened the body; whereas the mid-crust thinned under the graben systems. The rebounding uplifted body cooled, and then the graben system was occluded, which resulted in the crust-mantle isostatic adjustment and asthenospheric convection. As a result of the two extensional movements, the uplifted central Shandong block with the Tai-Lu-Yi area as the core stands highly above the surrounding plain characterized by graben systems. The present Mount Taishan forms the climax of the uplift.
基金The National Major Fundamental Research and Development Project of China under contract Nos G2000046703 and 2007CB411702the Scientific Research Fund of the Second Institute of Oceanography, State Oceanic Administration under contract No.JT0705
文摘The paper focuses on the characteristics of faulting and magmatism of the Okinawa Trough and the relation between them. En-echelon grabens are ranked oblique to the continental shelf edge uplift, and the Longwang uplift, the rifting block ridge in the northern segment and the ＂Mianhua uplift＂ in the southern segment have possibly preserved characteristics of volcanism and magmatism occurring with those rifting phases. The clockwise rotation of the southern Ryukyu Islands, driven by collision between Luzon and Taiwan, has played a key role in the crustal oceanization, enhancing the crustal extension of the southern segment and inducing volcanic magmatism in those grabens, among which the Yaeyama graben is a typical example of the presence of oceanic crust. Faulting and magmatism were mainly migrating towards the island arc asymmetrically. The crustal oceanization of the Okinawa Trough is difficultly interpreted by the linear magnetic anomaly model, which is fit for the symmetric spreading of the mid-oceanic ridges.
文摘The analysis of Earth’s crust movement vertical velocities was made both for separate regions, and averaged on regions. As input data coordinates and velocities of earth crust points, obtained in International Coordinate Systems ITRF2000, ITRF2005,ITRF2008 on the base of processing radio interferometric(VLBI), laser(SLR), Doppler(DORIS) and GPS observations was used. For the purpose of global analysis all input velocity values were averaged in the x trapezoids. For filling trapezoids the spherical function expansion to N=36 was made. Expansion harmonic coefficients allowed determine the global characteristics of earth crust movements both for all Earth, and for separate hemispheres, polar and equatorial regions, continents and oceans. It appears, that polar regions were risen, and equatorial ones were lowered, that can indicate the modern Earth oblateness reduction. The constructed maps of vertical velocities were compared with obtained by us map of earth crust strain distribution. It is appeared, that regions of modern earth surface rising(Fennoscandia, Canada, Antarctica) coincide with regions of vertical extension strain, and the lowering regions-with compression regions. Simultaneously with the determination of harmonious coefficients the mean-square error of approximation for expansion of power n=1 N and power dispersion were determined. Whereas the results converge badly and dispersion increased with the n grows, hence we can concludes, that vertical movements do not characterized global earth crust movement and denotes the unrelated character of these movement. Seemingly, the main cause of such movement origin is the local seismic events(earthquake, volcanic eruption and so on). It confirms by our conclusions about correspondence of vertical strain maximal gradient(and therefore vertical velocities) map of the earthquake distribution. In work the detailed analysis of obtained results for separate Earth’s regions was made.
