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Interactions between hotspots and the Southwest Indian Ridge during the last 90 Ma:Implications on the formation of oceanic plateaus and intra-plate seamounts

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Science China Earth sciences 2011年第8期54卷 1177-1188页

作者： ZHANG Tao 1,2,3,4,LIN Jian 5 & GAO JinYao 3,4 1 institute of geodesy and geophysics,chinese academy of sciences,Wuhan 430077,China 2 Graduate University of chinese academy of sciences,beijing 100049,China 3 The Second institute of Oceanography,State Oceanic Administrator,Hangzhou 310012,China 4 Key Laboratory of Submarine Geosciences,State Oceanic Administrator,Hangzhou 310012,China 5 Department of geology and geophysics,Woods Hole Oceanographic Institution,Woods Hole,MA 02543,USA institute of geodesy and geophysics Chinese Academy of Sciences Wuhan China Graduate University of chinese academy of sciences Beijing China The Second institute of Oceanography State Oceanic Administrator Hangzhou China Key Laboratory of Submarine Geosciences State Oceanic Administrator Hangzhou China

This study investigates the relationship between the hotspot-ridge interaction and the formation of oceanic plateaus and seamounts in the Southwest Indian *** first calculated the relative distance between the Southwest Indian Ridge (SWIR) and relevant hotspots on the basis of models of plate reconstruction,and then calculated the corresponding excess magmatic anomalies of the hotspots on the basis of residual bathymetry and Airy *** results reveal that the activities of the Marion hotspot can be divided into three main phases:interaction with the paleo-Rodrigues triple junction (73.6-68.5 Ma),interaction with the SWIR (68.5-42.7 Ma),and intra-plate volcanism (42.7-0 Ma).These three phases correspond to the formation of the eastern,central,and western parts of the Del Cano Rise,*** magnitude and apparent periodicity of the magmatic volume flux of the Marion hotspot appear to be dominated by the hotspot-ridge *** periodicity of the Marion hotspot is about 25 Ma,which is much longer than that of the Hawaii and Iceland hotspots (about 15 Ma).

关键词： Southwest Indian Ocean hotspot-ridge interaction magmatic volume flux oceanic plateaus seamounts

Ce Anomalies of the Yangtze Region,South China,through the Ordovician and Silurian Transition

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Journal of Earth Science 2009年第6期20卷 941-948页

作者：严德天张丽琴李双建 Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of GeosciencesWuhan institute of geology and geophysics Chinese Academy of Sciences School of geodesy and Geomatics Wuhan University Key Laboratory of Geospace Environment & geodesy of Ministry of Education Wuhan University Petroleum Exploration and Production institute of SINOPEC

Systematic Ce anomalies for whole-rock have been obtained from the shale-dominated, continuous, and pelagic sedimentary sequences spanning the Ordovician/Silurian （O/S） boundary at the Tieshui （铁水） of Xiushan （秀山）, Chongqing （重庆）, South China. Ce anomalies across the O/S boundary are recognized in three intervals, Wufeng （五峰）, Guanyinqiao （观音桥） and Longmaxi （龙马溪）. The calculated Ce/Ce＊ values of Wufeng Formation range from 0.84 to 0.96 （avg. 0.90）. In the Guanyinqiao Formation, the values of calculated Ce/Ce＊ range from 0.73 to 0.85 （avg. 0.79）. The Ce/Ce＊ values of uppermost Longmaxi Formation range from 0.87 to 0.96 （avg. 0.91）. All along the section, the magnitude of the Ce anomaly is always negative, but is more significant in the Guanyinqiao Formation. The relatively higher Ce/Ce＊ values in the Wufeng and Longmaxi shales are likely to be due to the sediments deposited under rather reducing conditions. The Ce anomaly apparently does play some regular roles in the anoxic events that accompany prominent mass extinctions, and this work provides new data of critical importance for constraining models on the end-Ordovician anoxic events and mass extinctions.

关键词： Ce anomaly redox mass extinction Ordovician/Silurian boundary Yangtze platform.

Uppermost mantle structure of the North China Craton:Constraints from interstation Pn travel time difference tomography

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Uppermost mantle structure of the North China Craton:Constra...

TECTONICS AND PALEOGEOGRAPHY OF THE SOUTH CHINA ARCHIPELAGO OROGENESIS IN THE PERMO-TRIASSIC

中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： LI ZhiWei~(1,2),HAO TianYao~(1*) & XU Ya~1 ~1Key Laboratory of Petroleum Resources Research,institute of geology and geophysics,chinese academy of sciences,beijing 100029,China ~2Key Laboratory of Dynamical geodesy,institute of geodesy and geophysics,chinese academy of sciences,Wuhan 430077,China

The uppermost mantle is the key area for exchange of heat flux and material convection between the crust and lithospheric mantle. Spatial variations of lithospheric thinning and dynamic processes in the North China Craton could inevitably induce the velocity heterogeneity in the uppermost *** this study,we used Pn arrivals from permanent seismic stations in North China and surrounding regions to construct a tomographic image of the North China *** tomographic method with Pn travel time difference data were used to study the velocity variations in the uppermost *** velocities in the uppermost mantle varied significantly in the Eastern,Central and Western blocks of the North China *** suggests that the lithosphere beneath different blocks of the North China Craton have experienced distinct tectonic evolutions and dynamic processes since the Paleozoic. The current uppermost mantle has been imprinted by these tectonic and dynamic *** Pn velocities are prominent beneath the Bohai Bay Basin in the Eastern Block of the North China Craton,suggesting residuals of the Archean lithospheric *** the Tanlu Fault Zone and Bohai Sea,slow Pn velocities are present in the uppermost mantle,which can be attributed to significant lithospheric thinning and asthenospheric *** newly formed lithospheric mantle beneath Yanshan Mountain may be the dominant reason for the existence of slow Pn velocities in this ***,the ancient lower crust and lithospheric mantle already have been *** the Central Block,significant slow Pn velocities are present in Taihangshan Mountain,which also extends northward to the Yinchuan-Hetao Rift on the northern margin of the Ordos Block and Yinshan *** characteristic probably is a result of hot asthenospheric upwelling along the active tectonic boundary on the margin of the Western *** protracted thermal erosion and underplating of hot asthenospheric upwelling may induce

关键词： North China Craton Lithospheric thinning Uppermost mantle Pn travel time difference Cratonic destruction

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Scientia Geologica Sinica 1999年第1期 17-29页

作者： Haihong Chen Wenjiao Xiao( Lab. of Lithosphere Tectonic Evolution, institute of geology. chinese academy of sciences, beijing 100029)

The geological and paleomagnetic investigations suggest that the blocks in South China, except for those rifted from late Paleozoic Gondwana such as the Shan-Thai-Malay and Hainan blocks, were separated by restricted back-arc basins not by large oceans. Most of these basins were probably collapsed in the early Mesozoic, leaving a few remnants of deep water sediments in the melange zones. South of the back-arc basins and remnant arcs lies a magmatic frontal arc which could be traced from the Lincang arc in eastern Yunnan to the Malay Peninsula and Borneo, and northward to coastal Fujian and probably to Japan. These arc terranes and back-arc basins might have formed an archipelago in Permo-Triassic time, an ancient analogue of Southeast Asia today.

关键词： Chen TECTONICS AND PALEOGEOGRAPHY OF THE SOUTH CHINA ARCHIPELAGO OROGENESIS IN THE PERMO-TRIASSIC Nature SLM Li

Contemporary crustal movement of continental China obtained by global positioning system(GPS) measurements

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chinese Science Bulletin 2001年第18期46卷 1552-1554,1588页

We obtain a unified horizontal velocity field of continental China and vicinity through measurements at 81 GPS stations provided by the National Key Infrastructure Project, Crustal Movement Observation Network of China. The velocity field delineates patterns of movements and deformation of active crustal blocks in continental China under the Eurasia-fixed reference frame. The space-based geodesy also clearly shows for the first time the horizontal movementand deformation of continental China induced by indentation of the Indian plate. The data provide kinematic constraints for simulating dynamic process of continental litho-spheric deformation.

关键词： crustal movement velocity field tectonic deformation.

Study on the Change of Frozen Soil in Russia （North Asia） Region Based on NOAA Image

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Study on the Change of Frozen Soil in Russia （North Asia） ...

Three-dimensional crustal density distribution beneath North China by sequential inversion of local earthquake traveltimes and gravity anomaly

2010 International Conference on Remote Sensing (ICRS 2010)

作者： Han Xu Sun Yiquan Chen Ying Feng Zhongke Gong Yinxi beijing Forestry University institute of GIS RS & GPS 10083 beijing ChinaCheng Yanpei CAGS institute of Hydrogeology and Environmental geology 050061 Shijiazhuang China

Frozen soil is a widespread kind of soil at high altitudes and high latitudes. It is divided into two parts, permafrost and seasonally frozen soil. It accounts for about 79% of northern hemisphere. As the largest country in the world, the area of Russia frozen soil occupies a large proportion. The use of satellite remote sensing technology has promoted the rapid development of permafrost research since 1970s. In this paper, NOAA remote sensing data preprocessing in Asian part of Russia was done. According to the band characteristics of AVHRR data, split window algorithm was used to calculate surface temperature. Thus, interpreted permafrost and seasonally frozen ground were interpreted, and added up the change of frozen soil area. The conclusion of this research is that permafrost is being degraded to seasonally frozen ground every year. In the end of this paper, the reasons and the hazards were analyzed.

关键词： Russia Frozen soil Split-window algorithms Land surface temperature

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Earthquake Science 2011年第2期24卷 135-141页

作者： Xinsheng Wang Jian Fang Houtse hsu Key Laboratory of Dynamic geodesy Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Graduate University of the chinese academy of sciences Beijing 100049 China

A three-dimensional crustal density model beneath North China is determined using P-wave traveltimes and gravity datum by sequential inversion method in this paper. To improve the uniqueness of the solution, we used a linear relationship between velocity and density to achieve mutual conversions and constraints between velocity difference and density difference. Algebraic reconstruction technique （ART） was used in density inversion, which highly improved the calculation speed comparing with common least squares method. The inversion results indicate that the crustal density beneath North China is extremely inhomogeneous with its distribution coherent with regional tectonics. The lower crust of Taihang mountain tectonic zone shows an obvious low density characteristic. We proposed that it may be an indicator of upwelling of mantle materials or partial melting of lowermost crust.

关键词： density distribution sequential inversion ART seismic tomography

Observations and modeling of flat subduction and its geological effects

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Science China Earth sciences 2020年第8期63卷 1069-1091页

作者： Zhiyong YAN Lin CHEN Xiong XIONG Kai WANG Renxian XIE Hou Tze hsu MOE Key Laboratory of Fundamental Physical Quantities Measurement&Hubei Key Laboratory of Gravitation and Quantum Physics PGMF and School of PhysicsHuazhong University of Science and TechnologyWuhan 430074China institute of geophysics and PGMF Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of geodesy and Earth s Dynamic Institute of Geodesy and GeophysicsChinese Academy of SciencesWuhan 430077China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China institute of geophysics and Geomatics China University of GeosciencesWuhan 430074China

Flat subduction refers to low-angle(<10°) or sub-horizontal subduction of oceanic slabs. Flat subduction is only recognized in ~10% of present-day subduction zones, but its impact on the behavior of the overriding plate is particularly *** example, flat subduction zones are typically associated with stronger earthquakes. The deformation caused by typical flat subduction will transfer from the trench to the overriding continental interior and form a broad magma belt. The formation mechanism of flat subduction has been linked to the relative buoyancy of subducted oceanic plateaus, overthrusting of the overriding plate, hydrodynamic suction, and trench retreat. However, these mechanisms remain debated. This paper systematically analyzes and summarizes previous studies on flat subduction, and outlines the possible geological effects of flat subduction, such as intracontinental orogeny and magmatism. Using examples from numerical modeling, we discuss the possible formation mechanisms. The most important factors that control the formation of flat subduction are associated with overthrusting of the overriding plate and the arrival of an oceanic plateau at the subduction zone. In addition, trench retreat is necessary to enable flat subduction. Hydrodynamic suction contributes to the reduction of the slab dip angle, but is insufficient to form flat subduction. Future numerical modeling of flat subduction should carry out three-dimensional high-resolution thermo-mechanical simulation, considering the influence of crustal eclogitization(negative buoyancy) and mantle serpentinization(positive buoyancy) of oceanic lithosphere, in combination with geological and geophysical data.

关键词： Flat subduction Magmatism Intracontinental orogeny Formation mechanism Numerical modeling

Effect of different inter-satellite range on measurement precision of Earth’s gravitational field from GRACE

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geodesy and Geodynamics 2012年第1期3卷 44-51页

作者： Zheng Wei hsu Houtse Zhong Min Yun Meijuan Zhou Xuhua State Key Laboratory of geodesy and Earth＇ s Dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Disaster Prevention Research institute Kyoto University Uji Kyoto 611-001l Japan Department of Applied Physics Wuhan University of Science and Technology Wuhan 430081 China Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China

The precision of Earth＇s gravitational field from GRACE up to degree and order 120 was studied for different inter-satellite ranges using the improved energy conservation principle. Our simulated result shows that： For long wavelength （L≤20） at degree 20, the cumulative geoid-height error gradually decreased with increasing range, from 0. 052 cm for 110 km to 1. 156 times and 1. 209 times as large for 220 km and 330 kin, respectively. For medium-wavelength （ 100 ≤ L ≤ 120） at degree 120, the cumulative geoid-height error de- creased from 13. 052 cm for 110 km, to 1. 327 times and 1. 970 times as large for the ranges of 220 km and 330 km, respectively; By adopting an optimal range of 220 ± 50 km, we can suppress considerably the loss of precision in the measurement of the Earth＇ s long-wavelength and medium-wavelength gravitational field.

关键词： GRACE inter-satellite range colored noise Earth' s gravitational field energy conservation principle