The Mohorovicic discontinuity(Moho)boundary separating the Earth’s crust and mantle reflects the evolutionary trajectory of the Earth’s crust,yielding crucial insights into crustal formation,tectonic evolution,and p...The Mohorovicic discontinuity(Moho)boundary separating the Earth’s crust and mantle reflects the evolutionary trajectory of the Earth’s crust,yielding crucial insights into crustal formation,tectonic evolution,and profound dynamic processes.However,the prevailing Moho models for China and its adjacent areas suffer from limited accuracy,owing to the irregular and sparse distribution of seismic data collection.In this study,we employ gravimetric data to derive Moho depth,and employ Bott’s regularization method,integrating gravity and seismic data to reconstruct the Moho structure with high precision in a three-dimensional framework across China and its adjacent areas.By optimizing gravity potential field separation and interface inversion techniques,we present a detailed and accurate zoning scheme for classifying China and its adjacent areas into 35 gradient belts,6 primary tectonic units,and 35 secondary tectonic units,based on the spatial distribution characteristics of the Moho discontinuity.Notably,our tectonic pattern division results surpass previous studies in terms of resolution,providing a wealth of tectonic information.Leveraging the Moho depth model of China and its adjacent areas,we discuss orogenic belts,sedimentary basins,fault systems,plate boundaries,and land-sea coupled tectonic patterns.We meticulously summarize the Moho depth distribution characteristics of each tectonic unit,while exploring the macrostructural framework and geological significance of the study area.Our findings highlight the close relationship between China and its adjacent areas Moho depth model and deep geodynamics,elucidating the tectonic evolution both between and within tectonic plates,as well as the tectonic effects induced by mantle dynamics.These insights have crucial implications for the study of deep geodynamics in China and its adjacent areas.展开更多
Mozambique's continental margin in East Africa was formed during the break-off stage of the east and west Gondwana lands. Studying the geological structure and division of continent-ocean boundary(COB) in Mozambiq...Mozambique's continental margin in East Africa was formed during the break-off stage of the east and west Gondwana lands. Studying the geological structure and division of continent-ocean boundary(COB) in Mozambique's continental margin is considered of great significance to rebuild Gondwana land and understand its movement mode. Along these lines, in this work, the initial Moho was fit using the known Moho depth from reflection seismic profiles, and a 3D multi-point constrained gravity inversion was carried out. Thus, highaccuracy Moho depth and crustal thickness in the study area were acquired. According to the crustal structure distribution based on the inversion results, the continental crust at the narrowest position of the Mozambique Channel was detected. According to the analysis of the crustal thickness, the Mozambique ridge is generally oceanic crust and the COB of the whole Mozambique continental margin is divided.展开更多
We estimated Moho depth beneath the southern Tanlu fault zone and its adjacent area using common-conversion-point(CCP)stacking of receiver functions,which were computed from teleseismic records of the CEArray.Our esti...We estimated Moho depth beneath the southern Tanlu fault zone and its adjacent area using common-conversion-point(CCP)stacking of receiver functions,which were computed from teleseismic records of the CEArray.Our estimated Moho depth matches well with 2-D profiles derived from active-source deep seismic reflection surveys,suggesting that the calculated the Moho depth map is likely accurate beyond the 2-D profiles.Overall,the estimated Moho depth map showed a high spatial correlation with tectonic provinces,i.e.,Moho topographic boundaries are in good agreement with geological boundaries.Beneath the Dabie orogenic belt and the mountainous areas in southern Anhui Province,the Moho lies relatively deep,and there is an obvious difference in Moho depth between the two sides of this segment of the Tanlu fault.We further selected four depth profiles with dense instrumentation to show Moho depth changes across different tectonic blocks in the study area.We saw two step-like changes in Moho depth beneath the Xiangfan-Guangji and Gushi-Feizhong,which run parallel along the WNW-ESE direction and delineate the southern and northern bounds of the northern Dabie orogenic belt,which is likely the suture zone between the North China Block and South China Block.Crust beneath the northeast corner of the study area is significantly thinner than other areas,which is consistent with the crustal detachment model proposed for suturing between the North and South China blocks in the region east to the Tanlu fault.展开更多
The Qinghai （青海）-Tibet plateau is the newest and biggest orogenic belt in the world and a natural laboratory for researching continental geodynamics, such as continent-continent collision, convergence, subduction,...The Qinghai （青海）-Tibet plateau is the newest and biggest orogenic belt in the world and a natural laboratory for researching continental geodynamics, such as continent-continent collision, convergence, subduction, and plateau uplift. From the 1950s to the present, there have been many active-source （deep seismic sounding and deep seismic reflection profiling） and passive-source seismic probing （broadband seismic observations） implemented to reveal the crust-mantle structure. In this article, the authors mainly summarize the three seismic probings to discuss the Moho depth of the Qinghai-Tibet plateau based on the previous summaries. The result shows that the Moho of the Qinghai-Tibet plateau is very complex and its depth is very different; the whole outline of it is that the Moho depth is deeper beneath the south than the north and deeper in the west than in the east. In the Qiangtang （羌塘） terrane, the hinterland of the Qinghai-Tibet plateau, the Moho is shallower than both the southern and the northern sides. The deepest Moho is 40 km deeper than the shallowest Moho. This trend records the crustal thickening and thinning caused by the mutual response between the India plate and the Eurasia plate, and the eastward mass flow in the Qinghai-Tibet plateau.展开更多
There is a long-term dispute at Moho depth across the Bangong-Nujiang suture (BNS). Due to the complicated and changeable seismic geological condition, it is not easy to acquire images of the reflective Moho in centra...There is a long-term dispute at Moho depth across the Bangong-Nujiang suture (BNS). Due to the complicated and changeable seismic geological condition, it is not easy to acquire images of the reflective Moho in central Tibet. In the support of the SinoProbe project, a series of deep seismic reflection profiles were conducted to image Moho structure across the BNS and the Qiangtang terrane. These profiles extend from the northern Lhasa terrane to the Qiangtang terrane crossing the BNS. Both shot gathers and migration data show clear Moho images beneath the BNS. The Moho depth varies from 75.1 km (~24 s TWT) beneath the northmost Lhasa terrane to 68.9 km (~22 s TWT) beneath southmost Qiangtang terrane, and rises smoothly to 62.6 km (~20 s TWT ) at ~28 km north of the BNS beneath the Qiangtang terrane. We speculate that the Moho appears a 6.2 km sharp offset across the BNS and becomes ~12.5 km shallower from the northmost Lhasa terrane to the south Qiangtang terrane at ~28 km north of the BNS. The viewpoint of Moho depth across the BNS based on deep seismic reflection data is inconsistent with the previous 20 km offset.展开更多
In this study,high-resolution Moho depth and average crustal V_(p)/V_(s) ratio distributions in northeast China were obtained through joint inversion of receiver functions and gravity data.The new joint inversion meth...In this study,high-resolution Moho depth and average crustal V_(p)/V_(s) ratio distributions in northeast China were obtained through joint inversion of receiver functions and gravity data.The new joint inversion method comprehensively considers the complementary imaging strengths of the receiver functions in the vertical direction and the gravity data in the lateral direction.To a certain extent,it can reduce the adverse effects of the receiver function data caused by the sedimentary layers of the basin,the inclination of the Moho,and the structure heterogeneity below the station.In preprocessing the receiver function data,a regularized virtual station network was constructed using the teleseismic receiver function waveform reconstruction method to improve the overall spatial resolution.To filter the gravity data,the velocity structure-guided gravity filtering method and gravity upward continuation were used for the shallower region above the Moho and the deeper region below the lithosphere,respectively.The newly obtained model shows that the Moho depths of the Hailar Basin,Erlian Basin,Sanjiang Basin,and Bohai Bay Basin are slightly shallower than those of the surrounding areas,while the Moho depths of the Greater Xing’an Range,Lesser Xing’an Range,and Zhangguangcai Range are slightly deeper.Compared with previous results,the refined Moho depth distribution obtained in this study has a better correspondence with topographic relief and basin boundaries,and the contrast is more evident across the north-south gravity gradient lineament(NSGL).In the eastern part of the Songliao Basin,the Moho is relatively shallow,and there is a high V_(p)/V_(s) ratio,which may have been caused by the intrusion of hot mantle materials into the crust induced by lateral extension of the Songliao Basin.The high V_(p)/V_(s) ratio of the crust below the Changbaishan volcanic area implies the existence of partial melting in the crust caused by upwelling hot mantle materials.展开更多
We apply the adaptive moving window method of Sun et al. to the most recent catalog data and the data recorded by portable stations to construct the velocity structure of the crust and upper mantle, and to determine t...We apply the adaptive moving window method of Sun et al. to the most recent catalog data and the data recorded by portable stations to construct the velocity structure of the crust and upper mantle, and to determine the depth of the Moho interface beneath the Tibetan plateau and other areas of China. We first select 2 600 locations in the study region with 1° intervals, then at each location invert for a five-layer 1-D P-wave velocity model from the surface down to the uppermost mantle by performing a Monte Carlo random search. The Moho depth at each location is then determined, and the Moho interface beneath the study region is obtained through proper interpolation with certain smoothing. Compared to depths obtained by previous studies, our results show more accurate Moho depths in the Tibetan plateau, Tianshan region and other areas of the study region.展开更多
Based on the method of "two-dimensional depth structure of the crust" proposed by Horiuchi et al., about 5000 arrival times of 303 local shallow earthquakes recorded by the Beijing Seismographic Network from...Based on the method of "two-dimensional depth structure of the crust" proposed by Horiuchi et al., about 5000 arrival times of 303 local shallow earthquakes recorded by the Beijing Seismographic Network from 1990 ~ 1993 are used to investigate the depth distribution of Moho discontinuity beneath Beijing and its adjacent area. We simultaneously determined the hypocenter parameters and P- and S-wave station corrections. The data of the North China Network were also investigated. The results are as follows: (1) The depth distribution of Moho discontinuity becomes shallower from the northwest to the southeast, i.e., in Zhangjiakou area, the Moho discontinuity is located at a depth range from 40~42 km. In the Beijing area, it is 36~39 km. However, at the eastern and southeastern part of this area, it is only 28-30 km and 30~32 km, respectively. (2) Beneath the Tangshan area, there is another elliptic interface shallower than the Moho discontinuity. Separately, its major and minor axis is approximately展开更多
A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques inclu...A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques include obtaining gravity data from the Gravity Field and Steady-State Ocean Circulation Explorer(GOCE),creating seismic profiles,analyzing the receiver functions of seismic data,obtaining information from boreholes,and providing geological interpretations.GOCE satellite gravity data were processed to construct a preliminary model based on nonlinear inversions of the data.A regional crustal thickness model was developed using receiver functions,seismic refraction profiles,and geological insights.The inverted model was validated using borehole data and compared with seismic estimates.The model exhibited strong consistency and revealed a correlation between crustal thickness,geology,and tectonics of Egypt.It showed that the shallowest depths of the Moho are located in the north along the Mediterranean Sea and in the eastern part along the Red Sea,reflecting an oceanic plate with a thin,high-density crust.The deepest Moho depths are located in the southwestern part of Egypt,Red Sea coastal mountains,and Sinai Peninsula.The obtained 3D model of crustal thickness provided finely detailed Moho depth estimates that aligned closely with geology and tectonic characteristics of Egypt,contributing valuable insights into the subsurface structure and tectonic processes of region.展开更多
Based on Moho and Curie depth,heat flow,and upper mantle S-wave velocity anomaly,we infer the thermo-chemical structure of the lithospheres in Africa and surrounding oceans.The Moho depth is derived from gravity anoma...Based on Moho and Curie depth,heat flow,and upper mantle S-wave velocity anomaly,we infer the thermo-chemical structure of the lithospheres in Africa and surrounding oceans.The Moho depth is derived from gravity anomaly using the Parker-Oldenburg method,with constraints from seismic Moho.Crustal stratification defined by Curie-Moho depth difference shows that thermal and strong compositional processes may have shaped the lithospheric architecture of the African continental plate.Moho and Curie depths indicate the southern and eastern African cratons have thermochemical structures different from the West African Craton.Large Curie-Moho depth difference in southern and eastern Africa aligns with the low velocity anomaly originated from the core-mantle boundary.Mantle upwelling from the African low-velocity anomaly presumably induced partial melting at great depth,and the release of mineral-rich fluid and large amounts of volatile components facilitates a regional metasomatism,and results in a depleted,predominantly felsic,low-density paramagnetic crust.Mantle xenolith in kimberlites and volcanic rocks supports metasomatism by melts transmitted through narrow conduits as an intermittent or continuous upward flux of mineral-rich fluid.Alignment of the Curie-Moho depth difference at the intra-plate volcanic province correlates with weak lithospheric strength along the corridor connecting the intra-plate volcanic province with the Ethiopian plateau,suggesting a pathway for thermochemical asthenospheric flow.Crustal stratification and compositional-driven density layering support crustal buoyancy and uplift in the Hoggar,and southern and eastern Africa.A magnetized uppermost mantle is prevalent in the entire oceanic region,except at large igneous provinces(LIPs),volcanic seamounts,and oceanic plateaus,which have partial paramagnetic crusts.Our results support thermochemical upwelling related to the low velocity anomaly beneath the African plate.展开更多
The Zhujiang(Pearl)River Mouth Basin(PRMB)is located in the northern part of the South China Sea,and it is one of China’s three major offshore hydrocarbon-rich basins,playing an indispensable role in meeting the coun...The Zhujiang(Pearl)River Mouth Basin(PRMB)is located in the northern part of the South China Sea,and it is one of China’s three major offshore hydrocarbon-rich basins,playing an indispensable role in meeting the country’s energy needs.Exploration for oil in the PRMB started early and has achieved remarkable results in some sags,but many sags have yet to yield significant discoveries,necessitating the search for new favorable exploration areas.The aim of this study is to analyze the deep structural characteristics of various sags in the PRMB and predict favorable exploration areas,providing corresponding support for the next strategic breakthrough in oil exploration.Some studies indicate a certain relationship between the Moho depth and crustal thickness and the occurrence of oil.In this paper,based on satellite altimetry gravity anomaly data,we utilize a Moho depth inversion method based on variable residual crustal density to obtain the Moho depth in the PRMB,from which the crustal thickness and crustal stretching factor of the basin are calculated.The results show that the Moho depth in the PRMB ranges from 10 km to 37 km,the crustal thickness ranges from 7 km to 35 km,and the crustal stretching factor ranges from 0.9 to 3.0.Finally,we propose a comprehensive evaluation scheme for oil resoureces based on the CRiteria Importance Through Intercriteria Correlation(CRITIC)method,which comprehensively evaluates multiple factors,such as the Cenozoic sedimentary filling scale,Cenozoic thickness,Moho depth,crustal thickness,and crustal stretching factor,and provides evaluation criteria for identifying hydrocarbon-rich sags.According to this evaluation scheme,the exploration potential is relatively high in the Liwan Sag,Jinghai Sag,Heshan Sag,and Jieyang Sag,which are favorable exploration areas.展开更多
首先研究了大型沉积盆地对地表重力异常的影响,然后基于Parker-Oldenburg迭代算法,利用经过沉积层改正的布格重力异常数据反演了中国西部的Moho面深度。结果表明,地壳浅层密度异常对地表重力异常和Moho面深度结果的影响较大,利用简化的...首先研究了大型沉积盆地对地表重力异常的影响,然后基于Parker-Oldenburg迭代算法,利用经过沉积层改正的布格重力异常数据反演了中国西部的Moho面深度。结果表明,地壳浅层密度异常对地表重力异常和Moho面深度结果的影响较大,利用简化的三层沉积层模型,计算出的中国西部沉积盆地的重力异常改正最大可达25 m Gal,由此引起的Moho面深度可达2.2 km,Moho面深度最终计算结果与区域最新研究成果相符合,因此,利用重力异常反演Moho面深度时,应考虑沉积层的影响以提高反演精度。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42474121 and 42192535)the Basic Frontier Science Research Program of the Chinese Academy of Sciences(Grant No.ZDBS-LY-DQC028).
文摘The Mohorovicic discontinuity(Moho)boundary separating the Earth’s crust and mantle reflects the evolutionary trajectory of the Earth’s crust,yielding crucial insights into crustal formation,tectonic evolution,and profound dynamic processes.However,the prevailing Moho models for China and its adjacent areas suffer from limited accuracy,owing to the irregular and sparse distribution of seismic data collection.In this study,we employ gravimetric data to derive Moho depth,and employ Bott’s regularization method,integrating gravity and seismic data to reconstruct the Moho structure with high precision in a three-dimensional framework across China and its adjacent areas.By optimizing gravity potential field separation and interface inversion techniques,we present a detailed and accurate zoning scheme for classifying China and its adjacent areas into 35 gradient belts,6 primary tectonic units,and 35 secondary tectonic units,based on the spatial distribution characteristics of the Moho discontinuity.Notably,our tectonic pattern division results surpass previous studies in terms of resolution,providing a wealth of tectonic information.Leveraging the Moho depth model of China and its adjacent areas,we discuss orogenic belts,sedimentary basins,fault systems,plate boundaries,and land-sea coupled tectonic patterns.We meticulously summarize the Moho depth distribution characteristics of each tectonic unit,while exploring the macrostructural framework and geological significance of the study area.Our findings highlight the close relationship between China and its adjacent areas Moho depth model and deep geodynamics,elucidating the tectonic evolution both between and within tectonic plates,as well as the tectonic effects induced by mantle dynamics.These insights have crucial implications for the study of deep geodynamics in China and its adjacent areas.
基金The National Natural Science Foundation of China under contract No. 42076078China–Mozambique Joint Cruise under contract No. GASI-01-DLJHJ-CM。
文摘Mozambique's continental margin in East Africa was formed during the break-off stage of the east and west Gondwana lands. Studying the geological structure and division of continent-ocean boundary(COB) in Mozambique's continental margin is considered of great significance to rebuild Gondwana land and understand its movement mode. Along these lines, in this work, the initial Moho was fit using the known Moho depth from reflection seismic profiles, and a 3D multi-point constrained gravity inversion was carried out. Thus, highaccuracy Moho depth and crustal thickness in the study area were acquired. According to the crustal structure distribution based on the inversion results, the continental crust at the narrowest position of the Mozambique Channel was detected. According to the analysis of the crustal thickness, the Mozambique ridge is generally oceanic crust and the COB of the whole Mozambique continental margin is divided.
基金This research is supported by Spark Program of Earthquake Sciences(No.XH20026)Joint Open Fund of Mengcheng National Geophysical Observatory(No.MENGO-202014).
文摘We estimated Moho depth beneath the southern Tanlu fault zone and its adjacent area using common-conversion-point(CCP)stacking of receiver functions,which were computed from teleseismic records of the CEArray.Our estimated Moho depth matches well with 2-D profiles derived from active-source deep seismic reflection surveys,suggesting that the calculated the Moho depth map is likely accurate beyond the 2-D profiles.Overall,the estimated Moho depth map showed a high spatial correlation with tectonic provinces,i.e.,Moho topographic boundaries are in good agreement with geological boundaries.Beneath the Dabie orogenic belt and the mountainous areas in southern Anhui Province,the Moho lies relatively deep,and there is an obvious difference in Moho depth between the two sides of this segment of the Tanlu fault.We further selected four depth profiles with dense instrumentation to show Moho depth changes across different tectonic blocks in the study area.We saw two step-like changes in Moho depth beneath the Xiangfan-Guangji and Gushi-Feizhong,which run parallel along the WNW-ESE direction and delineate the southern and northern bounds of the northern Dabie orogenic belt,which is likely the suture zone between the North China Block and South China Block.Crust beneath the northeast corner of the study area is significantly thinner than other areas,which is consistent with the crustal detachment model proposed for suturing between the North and South China blocks in the region east to the Tanlu fault.
基金supported by the National Natural Science Foundation of China (Nos. 40830316, 40874045)International Sciences and Technology Cooperation (No. 2006DFA21340)+5 种基金the Special Fund for Sciences and Technology Research of Public Welfare Trades (No. 200811021)the Key Innovation Project for Sciences and Technology of the Ministry of Land and Resources (No. 1212010711813)the China Geological Survey and Resources Land Investigation Project (No. 1212010611809)the Basic Outlay of Scientific Research Work from Ministry of Science and Technology of the People’s Republic of China (No. J0803)SINOPPROBE-II, the Ministry of Land and Resources of China (No. 2004DKA20280-2-5)Open Fund of Key Laboratory of Geo-detection (China University of Geosciences, Beijing) (No. GDL0603)
文摘The Qinghai （青海）-Tibet plateau is the newest and biggest orogenic belt in the world and a natural laboratory for researching continental geodynamics, such as continent-continent collision, convergence, subduction, and plateau uplift. From the 1950s to the present, there have been many active-source （deep seismic sounding and deep seismic reflection profiling） and passive-source seismic probing （broadband seismic observations） implemented to reveal the crust-mantle structure. In this article, the authors mainly summarize the three seismic probings to discuss the Moho depth of the Qinghai-Tibet plateau based on the previous summaries. The result shows that the Moho of the Qinghai-Tibet plateau is very complex and its depth is very different; the whole outline of it is that the Moho depth is deeper beneath the south than the north and deeper in the west than in the east. In the Qiangtang （羌塘） terrane, the hinterland of the Qinghai-Tibet plateau, the Moho is shallower than both the southern and the northern sides. The deepest Moho is 40 km deeper than the shallowest Moho. This trend records the crustal thickening and thinning caused by the mutual response between the India plate and the Eurasia plate, and the eastward mass flow in the Qinghai-Tibet plateau.
文摘There is a long-term dispute at Moho depth across the Bangong-Nujiang suture (BNS). Due to the complicated and changeable seismic geological condition, it is not easy to acquire images of the reflective Moho in central Tibet. In the support of the SinoProbe project, a series of deep seismic reflection profiles were conducted to image Moho structure across the BNS and the Qiangtang terrane. These profiles extend from the northern Lhasa terrane to the Qiangtang terrane crossing the BNS. Both shot gathers and migration data show clear Moho images beneath the BNS. The Moho depth varies from 75.1 km (~24 s TWT) beneath the northmost Lhasa terrane to 68.9 km (~22 s TWT) beneath southmost Qiangtang terrane, and rises smoothly to 62.6 km (~20 s TWT ) at ~28 km north of the BNS beneath the Qiangtang terrane. We speculate that the Moho appears a 6.2 km sharp offset across the BNS and becomes ~12.5 km shallower from the northmost Lhasa terrane to the south Qiangtang terrane at ~28 km north of the BNS. The viewpoint of Moho depth across the BNS based on deep seismic reflection data is inconsistent with the previous 20 km offset.
基金supported by the National Key R&D Program of China(Grant No.2022YFF0800701)the National Natural Science Foundation of China(Grant No.U1839205)。
文摘In this study,high-resolution Moho depth and average crustal V_(p)/V_(s) ratio distributions in northeast China were obtained through joint inversion of receiver functions and gravity data.The new joint inversion method comprehensively considers the complementary imaging strengths of the receiver functions in the vertical direction and the gravity data in the lateral direction.To a certain extent,it can reduce the adverse effects of the receiver function data caused by the sedimentary layers of the basin,the inclination of the Moho,and the structure heterogeneity below the station.In preprocessing the receiver function data,a regularized virtual station network was constructed using the teleseismic receiver function waveform reconstruction method to improve the overall spatial resolution.To filter the gravity data,the velocity structure-guided gravity filtering method and gravity upward continuation were used for the shallower region above the Moho and the deeper region below the lithosphere,respectively.The newly obtained model shows that the Moho depths of the Hailar Basin,Erlian Basin,Sanjiang Basin,and Bohai Bay Basin are slightly shallower than those of the surrounding areas,while the Moho depths of the Greater Xing’an Range,Lesser Xing’an Range,and Zhangguangcai Range are slightly deeper.Compared with previous results,the refined Moho depth distribution obtained in this study has a better correspondence with topographic relief and basin boundaries,and the contrast is more evident across the north-south gravity gradient lineament(NSGL).In the eastern part of the Songliao Basin,the Moho is relatively shallow,and there is a high V_(p)/V_(s) ratio,which may have been caused by the intrusion of hot mantle materials into the crust induced by lateral extension of the Songliao Basin.The high V_(p)/V_(s) ratio of the crust below the Changbaishan volcanic area implies the existence of partial melting in the crust caused by upwelling hot mantle materials.
基金supported by the Defense Threat Reduction Agency under Contract Number DTRA01-00-C-0024supported by Chinese Academy of Sciences fund KJCX2-EW-121
文摘We apply the adaptive moving window method of Sun et al. to the most recent catalog data and the data recorded by portable stations to construct the velocity structure of the crust and upper mantle, and to determine the depth of the Moho interface beneath the Tibetan plateau and other areas of China. We first select 2 600 locations in the study region with 1° intervals, then at each location invert for a five-layer 1-D P-wave velocity model from the surface down to the uppermost mantle by performing a Monte Carlo random search. The Moho depth at each location is then determined, and the Moho interface beneath the study region is obtained through proper interpolation with certain smoothing. Compared to depths obtained by previous studies, our results show more accurate Moho depths in the Tibetan plateau, Tianshan region and other areas of the study region.
基金This project was sponsored by the Joint Earthquake Science Foundation of China (Project No. 94080).
文摘Based on the method of "two-dimensional depth structure of the crust" proposed by Horiuchi et al., about 5000 arrival times of 303 local shallow earthquakes recorded by the Beijing Seismographic Network from 1990 ~ 1993 are used to investigate the depth distribution of Moho discontinuity beneath Beijing and its adjacent area. We simultaneously determined the hypocenter parameters and P- and S-wave station corrections. The data of the North China Network were also investigated. The results are as follows: (1) The depth distribution of Moho discontinuity becomes shallower from the northwest to the southeast, i.e., in Zhangjiakou area, the Moho discontinuity is located at a depth range from 40~42 km. In the Beijing area, it is 36~39 km. However, at the eastern and southeastern part of this area, it is only 28-30 km and 30~32 km, respectively. (2) Beneath the Tangshan area, there is another elliptic interface shallower than the Moho discontinuity. Separately, its major and minor axis is approximately
文摘A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques include obtaining gravity data from the Gravity Field and Steady-State Ocean Circulation Explorer(GOCE),creating seismic profiles,analyzing the receiver functions of seismic data,obtaining information from boreholes,and providing geological interpretations.GOCE satellite gravity data were processed to construct a preliminary model based on nonlinear inversions of the data.A regional crustal thickness model was developed using receiver functions,seismic refraction profiles,and geological insights.The inverted model was validated using borehole data and compared with seismic estimates.The model exhibited strong consistency and revealed a correlation between crustal thickness,geology,and tectonics of Egypt.It showed that the shallowest depths of the Moho are located in the north along the Mediterranean Sea and in the eastern part along the Red Sea,reflecting an oceanic plate with a thin,high-density crust.The deepest Moho depths are located in the southwestern part of Egypt,Red Sea coastal mountains,and Sinai Peninsula.The obtained 3D model of crustal thickness provided finely detailed Moho depth estimates that aligned closely with geology and tectonic characteristics of Egypt,contributing valuable insights into the subsurface structure and tectonic processes of region.
基金Supported by the National Natural Science Foundation of China(Nos.91858213,41776057,41761134051)part of the PhD work of O J AKINRINADE and the National Key Research and Development Program of China(Nos.2023 YFF 0803400,2023 YFF 0803404)。
文摘Based on Moho and Curie depth,heat flow,and upper mantle S-wave velocity anomaly,we infer the thermo-chemical structure of the lithospheres in Africa and surrounding oceans.The Moho depth is derived from gravity anomaly using the Parker-Oldenburg method,with constraints from seismic Moho.Crustal stratification defined by Curie-Moho depth difference shows that thermal and strong compositional processes may have shaped the lithospheric architecture of the African continental plate.Moho and Curie depths indicate the southern and eastern African cratons have thermochemical structures different from the West African Craton.Large Curie-Moho depth difference in southern and eastern Africa aligns with the low velocity anomaly originated from the core-mantle boundary.Mantle upwelling from the African low-velocity anomaly presumably induced partial melting at great depth,and the release of mineral-rich fluid and large amounts of volatile components facilitates a regional metasomatism,and results in a depleted,predominantly felsic,low-density paramagnetic crust.Mantle xenolith in kimberlites and volcanic rocks supports metasomatism by melts transmitted through narrow conduits as an intermittent or continuous upward flux of mineral-rich fluid.Alignment of the Curie-Moho depth difference at the intra-plate volcanic province correlates with weak lithospheric strength along the corridor connecting the intra-plate volcanic province with the Ethiopian plateau,suggesting a pathway for thermochemical asthenospheric flow.Crustal stratification and compositional-driven density layering support crustal buoyancy and uplift in the Hoggar,and southern and eastern Africa.A magnetized uppermost mantle is prevalent in the entire oceanic region,except at large igneous provinces(LIPs),volcanic seamounts,and oceanic plateaus,which have partial paramagnetic crusts.Our results support thermochemical upwelling related to the low velocity anomaly beneath the African plate.
基金The Fundamental Research Funds for the Central Universities,CHD,under contract No.300102264106the Shaanxi Natural Science Basic Research Program under contract No.2025JC-YBQN-370the Scientific and Technological Project of CNOOC Research Institute Co.,Ltd.under contract No.CCL2021RCPS0167KQN.
文摘The Zhujiang(Pearl)River Mouth Basin(PRMB)is located in the northern part of the South China Sea,and it is one of China’s three major offshore hydrocarbon-rich basins,playing an indispensable role in meeting the country’s energy needs.Exploration for oil in the PRMB started early and has achieved remarkable results in some sags,but many sags have yet to yield significant discoveries,necessitating the search for new favorable exploration areas.The aim of this study is to analyze the deep structural characteristics of various sags in the PRMB and predict favorable exploration areas,providing corresponding support for the next strategic breakthrough in oil exploration.Some studies indicate a certain relationship between the Moho depth and crustal thickness and the occurrence of oil.In this paper,based on satellite altimetry gravity anomaly data,we utilize a Moho depth inversion method based on variable residual crustal density to obtain the Moho depth in the PRMB,from which the crustal thickness and crustal stretching factor of the basin are calculated.The results show that the Moho depth in the PRMB ranges from 10 km to 37 km,the crustal thickness ranges from 7 km to 35 km,and the crustal stretching factor ranges from 0.9 to 3.0.Finally,we propose a comprehensive evaluation scheme for oil resoureces based on the CRiteria Importance Through Intercriteria Correlation(CRITIC)method,which comprehensively evaluates multiple factors,such as the Cenozoic sedimentary filling scale,Cenozoic thickness,Moho depth,crustal thickness,and crustal stretching factor,and provides evaluation criteria for identifying hydrocarbon-rich sags.According to this evaluation scheme,the exploration potential is relatively high in the Liwan Sag,Jinghai Sag,Heshan Sag,and Jieyang Sag,which are favorable exploration areas.
文摘首先研究了大型沉积盆地对地表重力异常的影响,然后基于Parker-Oldenburg迭代算法,利用经过沉积层改正的布格重力异常数据反演了中国西部的Moho面深度。结果表明,地壳浅层密度异常对地表重力异常和Moho面深度结果的影响较大,利用简化的三层沉积层模型,计算出的中国西部沉积盆地的重力异常改正最大可达25 m Gal,由此引起的Moho面深度可达2.2 km,Moho面深度最终计算结果与区域最新研究成果相符合,因此,利用重力异常反演Moho面深度时,应考虑沉积层的影响以提高反演精度。
