In the last decade a New Geophysics has been proposed,whereby the crust and uppermost ~400 km of the mantle of the Earth are so pervaded by closely-spaced stress-aligned microcracks(intergranular films of hydrated mel...In the last decade a New Geophysics has been proposed,whereby the crust and uppermost ~400 km of the mantle of the Earth are so pervaded by closely-spaced stress-aligned microcracks(intergranular films of hydrated melt in the mantle) that in situ rocks verge on failure by fracturing,and hence are critical-systems that impose a range of fundamentally-new properties on conventional sub-critical geophysics.Enough of these new properties have been observed to confirm that New Geophysics is a new understanding of fluid/rock deformation with important implications and applications.Evidence supporting New Geophysics has been published in a wide variety of publications.Here,for clarification,we summarise in one document the evidence supporting New Geophysics.展开更多
Geophysical methods have been applied to a wide range of hydrogeological problems. With improvement in geophysical inversion algorithms and measurement tools, significant achievements have been made in the characteriz...Geophysical methods have been applied to a wide range of hydrogeological problems. With improvement in geophysical inversion algorithms and measurement tools, significant achievements have been made in the characterization of subsurface architecture, time-lapse monitoring of hydrogeological process and contaminant plumes delineation. In this paper, we summarize the geophysical methods that are most widely used in hydrogeology including Electrical Resistivity Tomography(ERT), Induced Polarization(IP), Ground Penetrating Radar(GPR) and Electromagnetic Induction(EMI). Three examples including lab and field works are used to demonstrate current application of geophysical methods for characterizing subsurface architecture and contaminant plumes. Though great progress has been made in hydrogeohysics over the last few decades at home and abroad, challenges still remain in practical applications. More recently, hydrogeophysics continues to develop in the areas of establishment of hydrogeophysical models, large-scale architecture characterization, uncertainty analysis, biogeochemical process monitoring and ecosystem science.展开更多
This paper reviews a new understanding of shear-wave splitting (seismic-birefringence) that is a fundamental revision of conventional fluid-rock deformation. It is a New Geophysics with implications for almost all s...This paper reviews a new understanding of shear-wave splitting (seismic-birefringence) that is a fundamental revision of conventional fluid-rock deformation. It is a New Geophysics with implications for almost all solid-earth geosciences, including hydrocarbon exploration and production, and earthquake forecasting. Widespread observations of shear-wave splitting show that deformation in in situ rocks is controlled by stress-aligned fluid-saturated grain-boundary cracks and preferentially orientated pores and pore-throats pervasive in almost all igneous, metamorphic, and sedimentary rocks in the Earth's crust. These fluid-saturated microcracks are the most compliant elements of the rock-mass and control rock deformation. The degree of splitting shows that the microcracks in almost all rocks are so closely spaced that they verge on fracture-criticality and failure by fracturing, and are critical systems with the “butterfly wing's” sensitivity of all critical systems. As a result of this crack-criticality, evolution of fluid-saturated stress-aligned microcracked rock under changing conditions can be modelled with anisotropic poroelasticity (APE). Consequently, low-level deformation can be: monitored with shear-wave splitting; future behaviour calculated with APE; future behaviour predicted with APE, if the change in conditions can be quantified; and in principle, future behaviour controlled by feed-back. This paper reviews our current understanding of the New Geophysics of low-level pre-fracturing deformation.展开更多
Magma is transported in brittle rock by diking.Diking plays a key role in tectonic phenomena such as continental rifting and plate divergence at mid-ocean ridges.In spite of the importance of understanding how magma is
"Beyond 100: The next century in Earth and Space Science"The 27th IUGG General Assembly will be held July 8-18,2019 at the Palais des Congrès in Montréal,Québec,Canada.This is a special opport..."Beyond 100: The next century in Earth and Space Science"The 27th IUGG General Assembly will be held July 8-18,2019 at the Palais des Congrès in Montréal,Québec,Canada.This is a special opportunity for participants from Canada and from around the world to come together and share their science and culture.2019 marks the 100th anniversary of IUGG;we will look back on the accomplishments of the previous century of Earth and space science research,and forward to the next century of scientific advancement.Join us for a host of scientific activities,including special public lectures,keynote Union lectures and a wide variety of themed sessions.展开更多
The State Key Laboratory of Petroleum Resources and Prospecting in China University of Petroleum (Beijing) was designated to be a state key laboratory by the Ministry of Science and Technology in 2007. It was founde...The State Key Laboratory of Petroleum Resources and Prospecting in China University of Petroleum (Beijing) was designated to be a state key laboratory by the Ministry of Science and Technology in 2007. It was founded on the basis of the Key Laboratory of Hydrocarbon Accumulation Mechanisms of the Ministry of Education and CNPC Key Laboratory of Geophysics. Professor Hao Fang serves as the director of the laboratory. His main research interest is in hydrocarbon accumulation mechanisms.展开更多
A selection of a number of geophysical methods to solve different geological, geodynamical, environmental, archaeological and other problems usually has no theoretical substantiation. The solution to this “four color...A selection of a number of geophysical methods to solve different geological, geodynamical, environmental, archaeological and other problems usually has no theoretical substantiation. The solution to this “four color” mathematical problem is able to assume that two independent geophysical methods are sufficient theoretically to characterize the geological-geophysical peculiarities of the area under study.展开更多
The determination and monitoring of aquifer formations on the eastern border of Moroccan Gharb basin are very difficult because of their spatial and temporal variation. To delimit these formations, a geophysical surve...The determination and monitoring of aquifer formations on the eastern border of Moroccan Gharb basin are very difficult because of their spatial and temporal variation. To delimit these formations, a geophysical survey of 52 geoelectric soundings was performed with a mesh of 500 m and electrodes distance between 1000 m and 3000 m. Geoelectric sections and resistivity maps show a horst and graben structure. The correlation of existing oil drillings shows that the Jurassic and Neogene formations are both affected by normal faults causing Jurassic deposits collapse with local thickening of the Miocene deposits, and reverse faults delimiting tectonic slices due to tension caused by prerifaine nappe advance. This fact confirms the generated structure by the resistivity method. The isobath map of resistant formations's roof show average depths extending from 400 to 800 m for calcareous sandstone that are potential aquifers while oil drillings indicate over 1000 m depths.展开更多
Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon reservoirs.Seismic migration aims at obtaining structural images of subsurface geologic discontinuit...Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon reservoirs.Seismic migration aims at obtaining structural images of subsurface geologic discontinuities.More specifically,seismic migration estimates the reflectivity function(stacked average reflectivity or pre-stack angle-dependent reflectivity)from seismic reflection data.On the other hand,seismic inversion quantitatively estimates the intrinsic rock properties of subsurface formulations.Such seismic inversion methods are applicable to detect hydrocarbon reservoirs that may exhibit lateral variations in the inverted parameters.Although there exist many differences,pre-stack seismic migration is similar with the first iteration of the general linearized seismic inversion.Usually,seismic migration and inversion techniques assume an acoustic or isotropic elastic medium.Unconventional reservoirs such as shale and tight sand formation have notable anisotropic property.We present a linearized waveform inversion(LWI)scheme for weakly anisotropic elastic media with vertical transversely isotropic(VTI)symmetry.It is based on two-way anisotropic elastic wave equation and simultaneously inverts for the localized perturbations(ΔVp_(0)/Vp_(0)/Vs_(0)/Vs_(0)/,Δ∈,Δδ)from the long-wavelength reference model.Our proposed VTI-elastic LWI is an iterative method that requires a forward and an adjoint operator acting on vectors in each iteration.We derive the forward Born approximation operator by perturbation theory and adjoint operator via adjoint-state method.The inversion has improved the quality of the images and reduces the multi-parameter crosstalk comparing with the adjoint-based images.We have observed that the multi-parameter crosstalk problem is more prominent in the inversion images for Thomsen anisotropy parameters.Especially,the Thomsen parameter is the most difficult to resolve.We also analyze the multi-parameter crosstalk using scattering radiation patterns.The linearized waveform inversion for VTI-elastic media presented in this article provides quantitative information of the rock properties that has the potential to help identify hydrocarbon reservoirs.展开更多
Reservoir characterization refers to the process of creating a comprehensive model that characterizes the reservoir based on its ability to store and produce hydrocarbons.This includes analyzing reservoir fluid behavi...Reservoir characterization refers to the process of creating a comprehensive model that characterizes the reservoir based on its ability to store and produce hydrocarbons.This includes analyzing reservoir fluid behavior under various conditions and identifying optimal production techniques to maximize hydrocarbon recovery.For this,a holistic understanding is required that integrates data from geophysics,geostatistics,petrophysics,geology,and reservoir engineering.展开更多
Brazil annually faces significant challenges with mass movements, particularly in areas with poorly constructed housing, inadequate engineering, and lacking sanitation infrastructure. Campos do Jordão, in Sã...Brazil annually faces significant challenges with mass movements, particularly in areas with poorly constructed housing, inadequate engineering, and lacking sanitation infrastructure. Campos do Jordão, in São Paulo state, is a city currently grappling with these issues. This paper details a study conducted within a pilot area in Campos do Jordão, where geophysical surveys and geotechnical borehole data were integrated. The geophysical surveys provided 2D profiles, and samples were collected to analyse soil moisture and plasticity. These datasets were combined using a Cokriging-based model to produce an accurate representation of the subsurface conditions. The enhanced modelling of subsurface variability facilitates a deeper understanding of soil behavior, which can be used to improve landslide risk assessments. This approach is innovative, particularly within the international context where similar studies often do not address the complexities associated with urban planning deficits such as those observed in some areas of Brazil. These conditions, including the lack of proper sanitation and irregular housing, significantly influence the geological stability of the region, adding layers of complexity to subsurface assessments. Adapting geotechnical evaluation methods to local challenges offers the potential to increase the efficacy and relevance of geological risk management in regions with similar socio-economic and urban characteristics.展开更多
On the basis of the characteristics of geology and geophysics in North China, three types of lithosphere, namely, the cratonic, the orogenic and the rift lithospheres can be classified. In terms of petrological method...On the basis of the characteristics of geology and geophysics in North China, three types of lithosphere, namely, the cratonic, the orogenic and the rift lithospheres can be classified. In terms of petrological method (based on the information from Precambrian rock assemblages, igneous activities, deep-seated enclaves, etc.) and the relationship between seismic velocity and rock compositions, the crust-mantle petrological and chemical structure models can be set up. Researching results indicate that the geology and geophysics of North China platform bears the similar characteristics in comparison with those of the global typical cratons. The Eerduosi(Ordos) block located in the west of the North China Platform is a remnant of cratonic lithosphere after the North China platform had undergone “activation” in Mesozoic and “reconstruction” in Cenozoic times. The continental crust consists mainly of TTG rock assemblage while the subcontinental lithosphere mantle mainly consists of strongly depleted harzburgite. The craton was finally formed in late Archaean and early Proterozoic, and has been kept in stability up to present; its crustal-mantle petrological structures of lithosphere can be set up as a reference for the study of North China craton and even Sino-Korean craton. In the Mesozoic period, the middle and east areas of North China platform were activated in the Yanshanian orogenic process, the continental crust was reformed by material and heat-transfer of convective mantle and the original crustal TTG component was reconstructed to be granitic crust, and the subcontinental lithosphere man- tle was replaced by the Yanshanian harzburgite-lherzolite. The Yanshan-Taihang Mountains were the remnants of orogenic lithosphere after the rifting in eastern North China in Cenozoic. The present thickness of continental crust and lithosphere in the Yanshan-Taihang Mountains is not equal to their thickness during the Yanshanian orogenic movement because they had undergone the crustal extensional thinning in Cenozoic, however, the material and structure of lithosphere mantle-crust were formed during the Yanshanian orogenic movement. In the Cenozoic Period, the rift-type lithosphere, as represented by the North China plain, was formed by the continental rifting occurring in the eastern part of North China. The continental granitic crust, which had been “acidified” at the Yanshanian period, was basified again by the eruption of basalt magma along the continental rifting, and the subcontinental lithosphere mantle formed in Yanshanian was de- stroyed and replaced by the Himalayan mantle which consists mainly of lherzolite. Both the crust and the lithospheric mantle in the rift have undergone extensional thinning and thermal erosion at lithospheric-scale, the material and structure of the present mantle-crust lithosphere, attained from geophysical exploration, was formed in Cenozoic. The formation and evolution of litho- sphere in North China indicate that the material and heat transferred by convective mantle into the continental crust was the key for different types of lithosphere forming, and the crust-mantle petrologic structure was the records of lithosphere evolution, and it was the integrated results of the deep processes of the China continental dynamic system and the Pacific Plate subduction located in the eastern margin of the North China platform in Mesozoic-Cenozoic time.展开更多
A browser/server system has been developed for the purpose of marine geophysical data sharing based on WebGIS technology, which uses MapServer open source system and ORACLE Data- base Management System. The main steps...A browser/server system has been developed for the purpose of marine geophysical data sharing based on WebGIS technology, which uses MapServer open source system and ORACLE Data- base Management System. The main steps during development, including system design and imple- mentation, are discussed in this article. The system can provide convenient, efficient, and interactive marine geophysical information sharing and visualization services through Internet or Intranet to im- prove data exchange and utilization.展开更多
Comprehensive investigations along the Gyirong-Lugu-Sangehu geophysical profile in the western Xizang Plateau are presented. Analysis and interpretation of the lithospheric structure resulted in setting up of the geop...Comprehensive investigations along the Gyirong-Lugu-Sangehu geophysical profile in the western Xizang Plateau are presented. Analysis and interpretation of the lithospheric structure resulted in setting up of the geophysical methods and marks for the division of tectonic units in the lithospheric structure. Comprehensive geophysical survey in the remote west of Xizang is reported and some reliable geophysical evidence for deep structure division in the study region is provided. These lay a solid basis for probing into the mechanism of the Xizang Plateau uplift and geodynamics.展开更多
Ground penetrating radar(GPR)investigations have the potential to non-destructively detect buried or hidden targets and are therefore often used in forensic research.This study presents a particular application of GPR...Ground penetrating radar(GPR)investigations have the potential to non-destructively detect buried or hidden targets and are therefore often used in forensic research.This study presents a particular application of GPR methods to search for a missing person in a specific subsurface environment:a natural cave.The search for missing people in Italy is a problematic and delicate task that needs improvement.Results of this study highlight not only the ability to detect both hollow and forensic targets,but also precisely locate and define their geometries.Moreover,GPR findings efficiently focus archaeological excavation and body recovery in an exact area and help to minimise time digging in erroneous places.展开更多
文摘In the last decade a New Geophysics has been proposed,whereby the crust and uppermost ~400 km of the mantle of the Earth are so pervaded by closely-spaced stress-aligned microcracks(intergranular films of hydrated melt in the mantle) that in situ rocks verge on failure by fracturing,and hence are critical-systems that impose a range of fundamentally-new properties on conventional sub-critical geophysics.Enough of these new properties have been observed to confirm that New Geophysics is a new understanding of fluid/rock deformation with important implications and applications.Evidence supporting New Geophysics has been published in a wide variety of publications.Here,for clarification,we summarise in one document the evidence supporting New Geophysics.
基金funded by the National Natural Science Fund of China (NSFC)-Xinjiang No.U1503282the NSFC No.41030746,41672229 and 41172206
文摘Geophysical methods have been applied to a wide range of hydrogeological problems. With improvement in geophysical inversion algorithms and measurement tools, significant achievements have been made in the characterization of subsurface architecture, time-lapse monitoring of hydrogeological process and contaminant plumes delineation. In this paper, we summarize the geophysical methods that are most widely used in hydrogeology including Electrical Resistivity Tomography(ERT), Induced Polarization(IP), Ground Penetrating Radar(GPR) and Electromagnetic Induction(EMI). Three examples including lab and field works are used to demonstrate current application of geophysical methods for characterizing subsurface architecture and contaminant plumes. Though great progress has been made in hydrogeohysics over the last few decades at home and abroad, challenges still remain in practical applications. More recently, hydrogeophysics continues to develop in the areas of establishment of hydrogeophysical models, large-scale architecture characterization, uncertainty analysis, biogeochemical process monitoring and ecosystem science.
文摘This paper reviews a new understanding of shear-wave splitting (seismic-birefringence) that is a fundamental revision of conventional fluid-rock deformation. It is a New Geophysics with implications for almost all solid-earth geosciences, including hydrocarbon exploration and production, and earthquake forecasting. Widespread observations of shear-wave splitting show that deformation in in situ rocks is controlled by stress-aligned fluid-saturated grain-boundary cracks and preferentially orientated pores and pore-throats pervasive in almost all igneous, metamorphic, and sedimentary rocks in the Earth's crust. These fluid-saturated microcracks are the most compliant elements of the rock-mass and control rock deformation. The degree of splitting shows that the microcracks in almost all rocks are so closely spaced that they verge on fracture-criticality and failure by fracturing, and are critical systems with the “butterfly wing's” sensitivity of all critical systems. As a result of this crack-criticality, evolution of fluid-saturated stress-aligned microcracked rock under changing conditions can be modelled with anisotropic poroelasticity (APE). Consequently, low-level deformation can be: monitored with shear-wave splitting; future behaviour calculated with APE; future behaviour predicted with APE, if the change in conditions can be quantified; and in principle, future behaviour controlled by feed-back. This paper reviews our current understanding of the New Geophysics of low-level pre-fracturing deformation.
文摘Magma is transported in brittle rock by diking.Diking plays a key role in tectonic phenomena such as continental rifting and plate divergence at mid-ocean ridges.In spite of the importance of understanding how magma is
文摘"Beyond 100: The next century in Earth and Space Science"The 27th IUGG General Assembly will be held July 8-18,2019 at the Palais des Congrès in Montréal,Québec,Canada.This is a special opportunity for participants from Canada and from around the world to come together and share their science and culture.2019 marks the 100th anniversary of IUGG;we will look back on the accomplishments of the previous century of Earth and space science research,and forward to the next century of scientific advancement.Join us for a host of scientific activities,including special public lectures,keynote Union lectures and a wide variety of themed sessions.
文摘The State Key Laboratory of Petroleum Resources and Prospecting in China University of Petroleum (Beijing) was designated to be a state key laboratory by the Ministry of Science and Technology in 2007. It was founded on the basis of the Key Laboratory of Hydrocarbon Accumulation Mechanisms of the Ministry of Education and CNPC Key Laboratory of Geophysics. Professor Hao Fang serves as the director of the laboratory. His main research interest is in hydrocarbon accumulation mechanisms.
文摘A selection of a number of geophysical methods to solve different geological, geodynamical, environmental, archaeological and other problems usually has no theoretical substantiation. The solution to this “four color” mathematical problem is able to assume that two independent geophysical methods are sufficient theoretically to characterize the geological-geophysical peculiarities of the area under study.
文摘The determination and monitoring of aquifer formations on the eastern border of Moroccan Gharb basin are very difficult because of their spatial and temporal variation. To delimit these formations, a geophysical survey of 52 geoelectric soundings was performed with a mesh of 500 m and electrodes distance between 1000 m and 3000 m. Geoelectric sections and resistivity maps show a horst and graben structure. The correlation of existing oil drillings shows that the Jurassic and Neogene formations are both affected by normal faults causing Jurassic deposits collapse with local thickening of the Miocene deposits, and reverse faults delimiting tectonic slices due to tension caused by prerifaine nappe advance. This fact confirms the generated structure by the resistivity method. The isobath map of resistant formations's roof show average depths extending from 400 to 800 m for calcareous sandstone that are potential aquifers while oil drillings indicate over 1000 m depths.
文摘Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon reservoirs.Seismic migration aims at obtaining structural images of subsurface geologic discontinuities.More specifically,seismic migration estimates the reflectivity function(stacked average reflectivity or pre-stack angle-dependent reflectivity)from seismic reflection data.On the other hand,seismic inversion quantitatively estimates the intrinsic rock properties of subsurface formulations.Such seismic inversion methods are applicable to detect hydrocarbon reservoirs that may exhibit lateral variations in the inverted parameters.Although there exist many differences,pre-stack seismic migration is similar with the first iteration of the general linearized seismic inversion.Usually,seismic migration and inversion techniques assume an acoustic or isotropic elastic medium.Unconventional reservoirs such as shale and tight sand formation have notable anisotropic property.We present a linearized waveform inversion(LWI)scheme for weakly anisotropic elastic media with vertical transversely isotropic(VTI)symmetry.It is based on two-way anisotropic elastic wave equation and simultaneously inverts for the localized perturbations(ΔVp_(0)/Vp_(0)/Vs_(0)/Vs_(0)/,Δ∈,Δδ)from the long-wavelength reference model.Our proposed VTI-elastic LWI is an iterative method that requires a forward and an adjoint operator acting on vectors in each iteration.We derive the forward Born approximation operator by perturbation theory and adjoint operator via adjoint-state method.The inversion has improved the quality of the images and reduces the multi-parameter crosstalk comparing with the adjoint-based images.We have observed that the multi-parameter crosstalk problem is more prominent in the inversion images for Thomsen anisotropy parameters.Especially,the Thomsen parameter is the most difficult to resolve.We also analyze the multi-parameter crosstalk using scattering radiation patterns.The linearized waveform inversion for VTI-elastic media presented in this article provides quantitative information of the rock properties that has the potential to help identify hydrocarbon reservoirs.
文摘Reservoir characterization refers to the process of creating a comprehensive model that characterizes the reservoir based on its ability to store and produce hydrocarbons.This includes analyzing reservoir fluid behavior under various conditions and identifying optimal production techniques to maximize hydrocarbon recovery.For this,a holistic understanding is required that integrates data from geophysics,geostatistics,petrophysics,geology,and reservoir engineering.
文摘Brazil annually faces significant challenges with mass movements, particularly in areas with poorly constructed housing, inadequate engineering, and lacking sanitation infrastructure. Campos do Jordão, in São Paulo state, is a city currently grappling with these issues. This paper details a study conducted within a pilot area in Campos do Jordão, where geophysical surveys and geotechnical borehole data were integrated. The geophysical surveys provided 2D profiles, and samples were collected to analyse soil moisture and plasticity. These datasets were combined using a Cokriging-based model to produce an accurate representation of the subsurface conditions. The enhanced modelling of subsurface variability facilitates a deeper understanding of soil behavior, which can be used to improve landslide risk assessments. This approach is innovative, particularly within the international context where similar studies often do not address the complexities associated with urban planning deficits such as those observed in some areas of Brazil. These conditions, including the lack of proper sanitation and irregular housing, significantly influence the geological stability of the region, adding layers of complexity to subsurface assessments. Adapting geotechnical evaluation methods to local challenges offers the potential to increase the efficacy and relevance of geological risk management in regions with similar socio-economic and urban characteristics.
基金supported by the Special Program of the Ministry of Land and Resources of China(Grant Nos.200010103 and 20001010202)the Researching Project of Deep-Level Substance’s Model of China Lithosphere,the Key Laboratory of Lithosphere Tectonics and Explorat ion,China Univers ity of Geosciences,Ministry of Education of China(Grant Nos.2003009 and 2003010)+1 种基金the Project of Key Problem on the Granite Geology in China,China Geological Survey(Grant No.200113900018)the National Natural Science Foundation of China(Grant No.402344048).
文摘On the basis of the characteristics of geology and geophysics in North China, three types of lithosphere, namely, the cratonic, the orogenic and the rift lithospheres can be classified. In terms of petrological method (based on the information from Precambrian rock assemblages, igneous activities, deep-seated enclaves, etc.) and the relationship between seismic velocity and rock compositions, the crust-mantle petrological and chemical structure models can be set up. Researching results indicate that the geology and geophysics of North China platform bears the similar characteristics in comparison with those of the global typical cratons. The Eerduosi(Ordos) block located in the west of the North China Platform is a remnant of cratonic lithosphere after the North China platform had undergone “activation” in Mesozoic and “reconstruction” in Cenozoic times. The continental crust consists mainly of TTG rock assemblage while the subcontinental lithosphere mantle mainly consists of strongly depleted harzburgite. The craton was finally formed in late Archaean and early Proterozoic, and has been kept in stability up to present; its crustal-mantle petrological structures of lithosphere can be set up as a reference for the study of North China craton and even Sino-Korean craton. In the Mesozoic period, the middle and east areas of North China platform were activated in the Yanshanian orogenic process, the continental crust was reformed by material and heat-transfer of convective mantle and the original crustal TTG component was reconstructed to be granitic crust, and the subcontinental lithosphere man- tle was replaced by the Yanshanian harzburgite-lherzolite. The Yanshan-Taihang Mountains were the remnants of orogenic lithosphere after the rifting in eastern North China in Cenozoic. The present thickness of continental crust and lithosphere in the Yanshan-Taihang Mountains is not equal to their thickness during the Yanshanian orogenic movement because they had undergone the crustal extensional thinning in Cenozoic, however, the material and structure of lithosphere mantle-crust were formed during the Yanshanian orogenic movement. In the Cenozoic Period, the rift-type lithosphere, as represented by the North China plain, was formed by the continental rifting occurring in the eastern part of North China. The continental granitic crust, which had been “acidified” at the Yanshanian period, was basified again by the eruption of basalt magma along the continental rifting, and the subcontinental lithosphere mantle formed in Yanshanian was de- stroyed and replaced by the Himalayan mantle which consists mainly of lherzolite. Both the crust and the lithospheric mantle in the rift have undergone extensional thinning and thermal erosion at lithospheric-scale, the material and structure of the present mantle-crust lithosphere, attained from geophysical exploration, was formed in Cenozoic. The formation and evolution of litho- sphere in North China indicate that the material and heat transferred by convective mantle into the continental crust was the key for different types of lithosphere forming, and the crust-mantle petrologic structure was the records of lithosphere evolution, and it was the integrated results of the deep processes of the China continental dynamic system and the Pacific Plate subduction located in the eastern margin of the North China platform in Mesozoic-Cenozoic time.
基金supported by the Important National Science & Technology Specific Project of China (No.2011ZX05056001-02)the 863 High-Tech Program Fund of China (No.2008AA09Z304)
文摘A browser/server system has been developed for the purpose of marine geophysical data sharing based on WebGIS technology, which uses MapServer open source system and ORACLE Data- base Management System. The main steps during development, including system design and imple- mentation, are discussed in this article. The system can provide convenient, efficient, and interactive marine geophysical information sharing and visualization services through Internet or Intranet to im- prove data exchange and utilization.
基金Project supported by National "Eighth Five-Year" Climbing Project.
文摘Comprehensive investigations along the Gyirong-Lugu-Sangehu geophysical profile in the western Xizang Plateau are presented. Analysis and interpretation of the lithospheric structure resulted in setting up of the geophysical methods and marks for the division of tectonic units in the lithospheric structure. Comprehensive geophysical survey in the remote west of Xizang is reported and some reliable geophysical evidence for deep structure division in the study region is provided. These lay a solid basis for probing into the mechanism of the Xizang Plateau uplift and geodynamics.
文摘Ground penetrating radar(GPR)investigations have the potential to non-destructively detect buried or hidden targets and are therefore often used in forensic research.This study presents a particular application of GPR methods to search for a missing person in a specific subsurface environment:a natural cave.The search for missing people in Italy is a problematic and delicate task that needs improvement.Results of this study highlight not only the ability to detect both hollow and forensic targets,but also precisely locate and define their geometries.Moreover,GPR findings efficiently focus archaeological excavation and body recovery in an exact area and help to minimise time digging in erroneous places.