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1.
Based on the former workers study results such as numerical simulation of fluid mechanics,seismic tomography of the whole earth and igneous rocks,the basic characteristics of mantle plumes are summarized in detail,namely the mantle plume,from the D″layer near the core-mantle bouundary(CMB)of 2900 km deep,is characterized by the spape of large head and thin narrow conduit,by the physical property of high temperature and low viscosity.The LIP(large igneous province)is the best exhibition when the mantle plume ascends to the surface.According to the basic characteristics of the mantle plumes and the LIP,as well as the temporal-spatial relationships between the mantle plume and continental breakup,the detailed research on petrology,geochemistry,temporal-spatial distribution,tectonic background of the Cenozoic-Mesozoic igneous rocks and gravity anomaly distribution in East China has been done.As a result,the Mesozoic igneous rocks in Southeast China should not be regarded as an example of typical LIP related to mantle plumes.for their related characteristics are not consitent with those of the typical LIPs related to mantle plumes.The Cenozoic igneous rocks in Northeast China have no the typical characteristics of mantle plumes and hotspots,so the Cenozoic volcanism in Northeast China might have no the direct relationships with the activity of mantle plumes. 相似文献
2.
Tectonics of South China continent and its implications 总被引：36，自引：0，他引：36
ZHANG GuoWei GUO AnLin WANG YueJun LI SanZhong DONG YunPeng LIU ShaoFeng HE DengFa CHENG ShunYou LU RuKui YAO AnPing 《中国科学:地球科学(英文版)》2013,56(11):1804-1828
This paper aims at exploring the tectonic characteristics of the South China Continent(SCC)and extracting the universal tectonic rules from these characteristics,to help enrich the plate tectonic theory and better understand the continental dynamic system.For this purpose,here we conduct a multi-disciplinary investigation and combine it with the previous studies to reassess the tectonics and evolution of SCC and propose that the tectonic framework of the continent comprises two blocks,three types of tectonic units,four deformation systems,and four evolutionary stages with distinctive mechanism and tectonic characteristics since the Neoproterozoic.The four evolutionary stages are:(1)The amalgamation and break-up of the Neoproterozoic plates,typically the intracontinental rifting.(2)The early Paleozoic and Mesozoic intracontinental orogeny confined by plate tectonics,forming two composite tectonic domains.(3)The parallel operation of the Yangtze cratonization and intracontinental orogeny,and multi-phase reactivation of the Yangtze craton.(4)The association and differentiation evolution of plate tectonics and intracontinental tectonics,and the dynamic characteristics under the Meso-Cenozoic modern global plate tectonic regime. 相似文献
3.
《中国地震研究》1994,(1)
Mantle convection results in plate movement.Large-scale mantle convection causes the migration of materials between the mantle and the crust,which leads to the variation of Earth's rotation following the law of conservation of angular momentum.When the Earth's rotation varies,relative movements occur among the plates due to their inertia and different degrees of coupling with the mantle.These relative movements inevitably cause tensile development of fractures,folds,faults and earthquakes along plate boundaries.As a result,several seismic belts have formed along these boundaries.The boundary of the Pacific Plate is the largest seismic belt in the world.Each plate has been cut up into blocks of various sizes by faults.It is the relative movement of the blocks that acts as the major driving force of intraplate earthquakes.These earthquakes are distributed mainly in areas of intermediate latitudes in the Northern Hemisphere.In short,mantle convection,variation of the Earth's rotation and plate movement are 相似文献
4.
Preface to special issue on relationship between continental tectonics and the seismic activities of China,research techniques and methods 
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下载免费PDF全文 Rui Gao 《地震科学（英文版）》2016,29(2):57-59
正As an essential element in studying Earth Sciences,plate tectonics provides the scientific basis for understanding movement and tectonic interactions among different plates and related tectonic consequences,i.e.,natural hazards.The theory of plate tectonics was introduced to China in the early 1970s,about 10 years after this,scientific theory was firstly developed in the western 相似文献
5.
Introduction Mantle convection is thought to be the most effective way of heat transportation in the earth and the source of driving lithospheric plates (Elasser, 1971). The velocity field of plate motion can be split into poloidal and toroidal parts, which are corresponding to the vertical (i.e. radial) and horizontal motions, respectively, in global model. The toroidal component is manifested in the existences of transform faults and the poloidal one in the presences of convergence and diver… 相似文献
6.
Introduction The intraplate stresses are affected by two types of forces: one is called the first-order stresses (Zoback, 1992) or the long-wave components of stresses, which are closely related to the driving mechanism of the plate motions such as ridge push, continental collision resistance, slab pull (suc-tion) and mantle drag force (Richardson, 1992; WEI, 2000). This type of stress field is character-ized by a uniform feature in very large horizontal scale with 50 times or more of the th… 相似文献
7.
Subduction is the core process of plate tectonics. The mantle wedge in subduction-zone systems represents a key tectonic unit, playing a significant role in material cycling and energy exchange between Earth's layers. This study summarizes research progresses in terms of subduction-related peridotite massifs, including supra-subduction zone(SSZ) ophiolites and mantle-wedge-type(MWT) orogenic peridotites. We also provide the relevant key scientific questions that need be solved in the future. The mantle sections of SSZ ophiolites and MWT orogenic peridotites represent the mantle fragments from oceanic and continental lithosphere in subduction zones, respectively. They are essential targets to study the crust-mantle interaction in subduction zones. The nature of this interaction is the complex chemical exchanges between the subducting slab and the mantle wedge under the major control of physical processes. The SSZ ophiolites can record melt/fluid-rock interaction, metamorphism,deformation, concentration of metallogenic elements and material exchange between crust and mantle, during the stages from the generation of oceanic lithosphere at spreading centers to the initiation, development, maturation and ending of oceanic subduction at continental margins. The MWT orogenic peridotites reveal the history of strong metamorphism and deformation during subduction, the multiple melt/fluid metasomatism(including silicatic melts, carbonatitic melts and silicate-bearing C-HO fluids/supercritical fluids), and the complex cycling of crust-mantle materials, during the subduction/collision and exhumation of continental plates. In order to further reveal the crust-mantle interaction using subduction-zone peridotites, it is necessary to utilize high-spatial-resolution and high-precision techniques to constrain the complex chemical metasomatism, metamorphism,deformation at micro scales, and to reveal their connections with spatial-temporal evolution in macro-scale tectonics. 相似文献
8.
Xiaobin Cao Huiming Bao Caihong Gao Yun Liu Fang Huang Yongbo Peng Yining Zhang 《Acta Geochimica》2019,(3):327-334
Understanding the origin of ocean island basalts(OIB) has important bearings on Earth's deep mantle.Although it is widely accepted that subducted oceanic crust, as a consequence of plate tectonics, contributes material to OIB's formation, its exact fraction in OIB's mantle source remains ambiguous largely due to uncertainties associated with existing geochemical proxies. Here we show, through theoretical calculation, that unlike many known proxies, triple oxygen isotope compositions(i.e.D^(17 )O) in olivine samples are not affected by crystallization and partial melting. This unique feature, therefore, allows olivine D^(17 )O values to identify subducted oceanic crusts in OIB's mantle source. Furthermore, the fractions of subducted ocean sediments and hydrothermally altered oceanic crust in OIB's mantle source can be quantified using their characteristic D^(17 )O values. Based on published D^(17 )O data, we estimated the fraction of subducted oceanic crust to be as high as 22.3% in certain OIB, but the affected region in the respective mantle plume is likely to be limited. 相似文献
9.
Luo Wei Luo Zhuoli and Chen ShangpingNational Center for Seismic Data Informanon SSB Beijing China Center for Analysis Prediction SSB Beijing China 《中国地震研究》1996,(3)
In this work,the vertical deformation,horizontal displacement,and stress fields of arcuate tectonics are theoretically derived from the horizontal tectonic stress; then the characteristics of tectonic movement,seismicity,and focal mechanism of arcuate tectonics of the entire world are explained.It is pointed out that the island arc and other arcuate tectonics are gradually developed under the displacement and stress fields of the arcuate tectonics and that the under-thrusting action of the ocean plate is secondary.The distance formulas between the volcanic arc and the trench are suggested and also that theoretical results are consistent with actual data. 相似文献
10.
Based on the polarization analysis of teleseismic SKS waveform data recorded at 49 seismic stations in Capital Area Seismograph Network,the SKS fast-wave direction and the delay time between the fast and slow shear waves at each station were determined by using the grid searching method of minimum transverse energy and the stacking analysis method,and then we acquired the image of upper mantle anisotropy in Capital area.In the study area,the fast-wave polarization direction is basically WNW-ESE,and the delay time falls into the interval from 0.56 s to 1.56 s.The results imply that the upper mantle anisotropy in Capital area is mainly caused by the subduc-tion of the Pacific plate to Eurasian plate.The subduction has resulted in the asthenospheric material deformation in Capital area,and made the alignment of upper mantle peridotite lattice parallel to the deformation direction.And the collision between the Indian and Eurasian plates made the crust of western China thickening and uplifting and material eastwards extruding,and then caused the upper mantle flow eastwards,and made the upper mantle de-formation direction parallel to the fast-wave direction.The deformation model of the crust and upper mantle is possibly vertically coherent deformation by comparing the fast-wave polarization direction with the direction of lithospheric extension and the GPS velocity direction. 相似文献
11.
It is generally believed a variation of 3He/4He isotopic ratios in the mantle is due to only the decay of U and Th,which produces4 He as well as heat.Here we show that not only3He/4He isotopic ratios but also helium contents can be fractionated by thermal diffusion in the lower mantle.The driving force for that fractionation is the adiabatic or convective temperature gradient,which always produces elemental and isotopic fractionation along temperature gradient by thermal diffusion with higher light/heavy isotopic ratio in the hot end.Our theoretical model and calculations indicate that the lower mantle is helium stratified,caused by thermal diffusion due to*400℃temperature contrast across the lower mantle.The highest3He/4He isotopic ratios and lowest He contents are in the lowermost mantle,which is a consequence of thermaldiffusion fractionation rather than the lower mantle is a primordial and undegassed reservoir.Therefore,oceanicisland basalts derived from the deepest lower mantle with high3He/4He isotopic ratios and less He contents—the long-standing helium paradox,is solved by our model.Because vigorous convection in the upper mantle had resulted in disordered or disorganized thermal-diffusion effects in He,Mid-ocean ridge basalts unaffected by mantle plume have a relatively homogenous and lower!3He/4He isotopic compositions.Our model also predicts that 3He/4He isotopic ratios in the deepest lower mantle of early Earth could be even higher than that of Jupiter,the initial He isotopic ratio in our solar system,because the temperature contrast across the lower mantle in the early Earth is the largest and less4 He had been produced by the decay of U and Th.Moreover,the early helium-stratified lower mantle owned the lowest He contents due to over-degassing caused by the largest temperature contrast.Consequently,succeeding evolution of the lower mantle is a He ingassed process due to secular cooling of the deepest mantle.This explains why significant amount of He produced by the decay of U and Th in the lower mantle were not released,another long-standing heat–helium paradox. 相似文献
12.
Using over 3 500 first P arrival times recorded by nine digital seismic stations from Hainan Digital Seismic Net-work during 1999～2005,a 3-D P-wave velocity model of the crust under Hainan Island and adjacent regions has been determined. The results show that the pattern of velocity anomalies in the shallower upper crust is somewhat associated with the surface geological tectonics in the region. A relative low-velocity anomaly appears north of the Wangwu-Wenjiao fault zone and a relative high-velocity anomaly appears south of the Wangwu-Wenjiao fault zone,corresponding to the depressed areas in north Hainan Island,where many volcanoes are frequently active and geothermal values are relatively higher,and the uplifted and stable regions in central and south of the Hainan Is-land. In the middle and lower crust velocities are relatively lower in east Hainan than those in west Hainan,possi-bly suggesting the existence of the upwelling of hot materials from the mantle in east Hainan. The pattern of veloc-ity anomalies also indicates that NW faults,i.e.,the Puqian-Qinglan fault,may be shallower,while the E-W Wangwu-Wenjiao fault may be deeper,which perhaps extends down to Moho depth or deeper. 相似文献
13.
《中国科学:地球科学(英文版)》2021,(9)
The Archean mantle lithosphere beneath the North China Craton(NCC) was transformed in the Mesozoic, leading to the craton destruction. Despite the significant breakthroughs in the craton studies, lithospheric transformation mechanisms are yet to be fully understood. Compositional variations of mantle-derived rocks and xenoliths provide insights into the nature of the mantle lithosphere before and after the craton destruction. The Paleozoic lithosphere of the NCC is ～200 km thick. It has a refractory mantle with an evolved isotopic signature. The Mesozoic mantle lithosphere was relatively fertile and highly heterogeneous. In the Cenozoic, the lithosphere in the eastern NCC is about 60–80 km thick. It has an oceanic-type mantle that is fertile in composition and depleted in the Sr-Nd isotopic signature. The Central Zone lithosphere is 100 km thick and has a double-layer mantle with an old upper layer and a new lower layer. The Western Block has a lithosphere of ～200 km thick. The lithospheric mantle beneath the southern and northern margins and eastern part of the NCC has been transformed significantly by peridotite-melt reactions due to the multiple subductions of adjacent plates since the Paleozoic. Paleo-Pacific subduction and the associated dynamic processes significantly alter the lithosphere based on the distribution of craton destruction. The involved mechanisms include mechanical intrusion of subduction plates, melt/fluid erosion, and local delamination. The lithospheric thinning of ～120 km is relevant to the continental extension caused by subduction plate rollback and trench retreat. 相似文献
14.
Teleseismic receiver functions and travel-time residuals along the north Hi-Climb broadband seismic array in the central-southern Qinghai-Tibet Plateau show that the lithosphere structures in the central and western Qinghai-Tibet Plateau are different. In the central Qinghai-Tibet Plateau, the Indian Plate is northward subducted beneath the Qiangtang block and arrives at the greatest depth beneath the central-southern Qiangtang block. The delaminated Indian lithospheric slab remains beneath the central Lhasa block to a depth possibly greater than that of the upper interface of the mantle transform zone. In the western Qinghai-Tibet Plateau, the Indian lithospheric plate is gently northward subducted and may have arrived to the south of Tarim plate. Due to the resistance from the gently northward subduction of the Indian mantle lithosphere in the western Qinghai-Tibet Plateau, the upwelling mantle material be-neath the Qiangtang block moves mostly toward the east to bring about the lateral eastward flow of the deep mantle hot material in the central Qinghai-Tibet Plateau. 相似文献
15.
IntroductionAnisotropy is a universal phenomenon in the upper mantle. The mechanisms, which cause elastic anisotropy of in-situ rocks, include lattice preferred orientation of the minerals composing the rocks and preferred orientation of magma chambers. Lattice preferred orientation (LPO) of olivine is widely believed to be the dominant cause of the upper mantle anisotropy. The observational results of the upper mantle anisotropy can be explained by tectonic process relating to plate motion.… 相似文献
16.
JianChang Zheng ZhaoGuo Huang Zhi Wu XiQing Hao JiaLun Ji BaiQi Ning LianHuan Hu XiuKuan Zhao GuoZhu Li 《中国科学:地球科学(英文版)》2016,59(8):1692-1699
Equatorial spread-F (ESF) backscatter plumes are often observed in radar range-time-intensity (RTI) maps at low latitude. Except case studies, few statistical investigations on the onset locations of scintillation-producing ESF plumes at given sites have been conducted. In this study, a statistical analysis is carried out on onset locations of ESF backscatter plumes observed at a low-latitude location Sanya (18.4°N, 109.6°E; dip lat 12.8°N) during equinoctial months of 2013. By employing a tracing method to locate backscatter plumes, we estimate the onset longitudes of periodic plumes obtained from the Sanya VHF radar five-beam steering measurements. The results show that the inter-plume distances (in longitude) are mostly confined within 200–600 km, and the ESF plumes producing ionospheric scintillations over Sanya are almost exclusively generated at the longitudes of 94°–110°E. The results indicate the necessity to monitor ESF plume initial generation in the longitude region of 94°–110°E to better understand the day-to-day variability in the occurrence of ionospheric scintillations over Sanya. 相似文献
17.
Introduction In order to understand the formation of the geological structure and its evolution of the Asian continent, it is needed to investigate the driving forces from the around continents and oceans and from its underlying mantle as well. The super parallel computer has been used to simulate the geodynamical processes in the lithosphere and mantle for a long time in many international works (Bird, 1995; Tackley, 1995). We also calculated the patterns of the global mantle convection on o… 相似文献
18.
Bagus Jaya Santosa 《中国地震研究》2008,22(2):206-217
The S wave velocity structure of the earth below Eastern Southeast Asia has been investigated by analyzing the seismogram from surface wave to multiple depth waves in the time domain and three Cartesian components simultaneously. The wave passes across the front area of subduction zone between the Philippine plate and the Asian plate. The main data are waveform comparisons, instead of the arrival times. The synthetic seismogram is calculated using the GEMINI method. The synthetic seismogram constructed by PREMAN global earth model deviates greatly from the measured one. To solve this problem, corrections are needed for the β speed structure. Corrections cover the gradient change of βh, which turns from negative to positive in upper mantle layers as in the PREMAN, change of earth crust depth and change of zero order coefficients of β velocity function in all earth mantle layers. So, the fitting is obtained, as well as the arrival time or the waveform of Love and Rayleigh surface waves, the S wave and the repetitive depth waves ScS2 and ScS3. This result reveals that the Southeast Asia, being stretched due to tectonic release, has a mantle in some parts with negative anomaly of S wave velocity and vertical anisotropy in all earth mantle layers. 相似文献
19.
Cao Shuai Zhang Keliang Wei Dongping 《中国地震研究》2010,(3):344-352
Based on their Euler poles,we calculated the relative velocities between every two plates in the typical global plate motion models,respectively,and estimated the area change along these boundaries. In our calculations,plates on both sides accommodated area changes depending on the boundary types: extensional, convergent or transform, so we can estimate area change of each plate and then globally. Our preliminary results show that the area of the southern hemisphere increased while that of the northern hemisphere decreased over the past 1 million years,and global area has increased by 26,000km2 to 36,000km2,which corresponds to the 160m～250m increment on the Earth's radius if all these area increments are attributed to Earth's expansion. Taking the NUVEL-1 model as an example,of the 14 plates in this model,11 are decreasing,but the global area has increased because of the larger increment amount from Africa,North America and Antarctica. Finally,we also discussed factors affecting the global area change such as subduction zone retreating and back-arc spreading. 相似文献
20.
Introduction The velocity field of surface plate motion can be split into a poloidal and a toroidal parts.At the Earth′s surface,the toroidal component is manifested by the existence of transform faults,and the poloidal component by the presence of convergence and divergence,i.e.spreading and subduc-tion zones.They have coupled each other and completely depicted the characteristics of plate tec-tonic motions.The mechanism of poloidal field has been studied fairly clearly which is related to … 相似文献