The chirp sub-bottom profiler,for its high resolution,easy accessibility and cost-effectiveness,has been widely used in acoustic detection.In this paper,the acoustic impedance and grain size compositions were obtained...The chirp sub-bottom profiler,for its high resolution,easy accessibility and cost-effectiveness,has been widely used in acoustic detection.In this paper,the acoustic impedance and grain size compositions were obtained based on the chirp sub-bottom profiler data collected in the Chukchi Plateau area during the 11th Arctic Expedition of China.The time-domain adaptive search matching algorithm was used and validated on our established theoretical model.The misfit between the inversion result and the theoretical model is less than 0.067%.The grain size was calculated according to the empirical relationship between the acoustic impedance and the grain size of the sediment.The average acoustic impedance of sub-seafloor strata is 2.5026×10^(6) kg(s m^(2))^(-1)and the average grain size(θvalue)of the seafloor surface sediment is 7.1498,indicating the predominant occurrence of very fine silt sediment in the study area.Comparison of the inversion results and the laboratory measurements of nearby borehole samples shows that they are in general agreement.展开更多
The giant Central Asian Orogenic Belt is an extensive accretionary orogen,of which the Solonker suture,as a major regional suture,coincides closely with an early Permian paleobiogeographical boundary.This suture is co...The giant Central Asian Orogenic Belt is an extensive accretionary orogen,of which the Solonker suture,as a major regional suture,coincides closely with an early Permian paleobiogeographical boundary.This suture is considered to mark the location of the final closure of the Paleo-Asian Ocean between the North China Craton and the Mongolian Terrane.Although the closure time of the Paleo-Asian Ocean along the Solonker suture has generally been regarded as Late Permian-Early Triassic,uncertainty remains because of a lack of typical collisionrelated features(e.g.,high-grade regional metamorphism and well-developed fold-thrust structures)and a scarcity of outcrops.The present study reports Early Permian foliated gabbros and dikes(288-275 Ma)and Middle-Late Permian undeformed layered gabbros,strongly peraluminous granites,and I-type granites(265-254 Ma)in the Xinhure area along the northern margin of the North China Craton.The Early Permian foliated intrusions have a subduction-related geochemical signature and were derived from partial melting of lithospheric mantle modified by subduction-related melts or fluids at the active margin of the North China Craton.In contrast,the Late Permian undeformed layered gabbros and strongly peraluminous granites were derived from partial melting of lithospheric mantle and middle-upper crust,respectively,triggered by asthenospheric upwelling.Therefore,a transition from an end-compressional to an extensional environment according to a transition from collision termination to postcollision of the North China Craton and Mongolian Terrane may have occurred between 275 Ma and 262 Ma.This time span can be considered as the final closure time of the Paleo-Asian Ocean along the Solonker suture.展开更多
Objective The NE China is located in the eastern segment of the Central Asian Orogenic Belt（CAOB）,which is a large accretionary orogen between the Siberian Craton and the North China Craton（NCC）.Many researches ha...Objective The NE China is located in the eastern segment of the Central Asian Orogenic Belt（CAOB）,which is a large accretionary orogen between the Siberian Craton and the North China Craton（NCC）.Many researches have discussed about the evolution of the Paleo-Asian Ocean（PAO）in the eastern CAOB.However,展开更多
基金supported by the National Key R&D Program of China (No.2021YFC2801202)the National Natural Science Foundation of China (No.42076224)the Fundamental Research Funds for the Central Universities (No.202262012)。
文摘The chirp sub-bottom profiler,for its high resolution,easy accessibility and cost-effectiveness,has been widely used in acoustic detection.In this paper,the acoustic impedance and grain size compositions were obtained based on the chirp sub-bottom profiler data collected in the Chukchi Plateau area during the 11th Arctic Expedition of China.The time-domain adaptive search matching algorithm was used and validated on our established theoretical model.The misfit between the inversion result and the theoretical model is less than 0.067%.The grain size was calculated according to the empirical relationship between the acoustic impedance and the grain size of the sediment.The average acoustic impedance of sub-seafloor strata is 2.5026×10^(6) kg(s m^(2))^(-1)and the average grain size(θvalue)of the seafloor surface sediment is 7.1498,indicating the predominant occurrence of very fine silt sediment in the study area.Comparison of the inversion results and the laboratory measurements of nearby borehole samples shows that they are in general agreement.
基金supported by the National Natural Science Foundation of China(Grant Nos.41402042,41002064)Fundamental Research Funds for the Central Universities(Grant Nos.310827172006,300102278402)Geological investigation work project of China Geological Survey(No.12120115069701)。
文摘The giant Central Asian Orogenic Belt is an extensive accretionary orogen,of which the Solonker suture,as a major regional suture,coincides closely with an early Permian paleobiogeographical boundary.This suture is considered to mark the location of the final closure of the Paleo-Asian Ocean between the North China Craton and the Mongolian Terrane.Although the closure time of the Paleo-Asian Ocean along the Solonker suture has generally been regarded as Late Permian-Early Triassic,uncertainty remains because of a lack of typical collisionrelated features(e.g.,high-grade regional metamorphism and well-developed fold-thrust structures)and a scarcity of outcrops.The present study reports Early Permian foliated gabbros and dikes(288-275 Ma)and Middle-Late Permian undeformed layered gabbros,strongly peraluminous granites,and I-type granites(265-254 Ma)in the Xinhure area along the northern margin of the North China Craton.The Early Permian foliated intrusions have a subduction-related geochemical signature and were derived from partial melting of lithospheric mantle modified by subduction-related melts or fluids at the active margin of the North China Craton.In contrast,the Late Permian undeformed layered gabbros and strongly peraluminous granites were derived from partial melting of lithospheric mantle and middle-upper crust,respectively,triggered by asthenospheric upwelling.Therefore,a transition from an end-compressional to an extensional environment according to a transition from collision termination to postcollision of the North China Craton and Mongolian Terrane may have occurred between 275 Ma and 262 Ma.This time span can be considered as the final closure time of the Paleo-Asian Ocean along the Solonker suture.
基金supported by the National Natural Science Foundation of China(grants No.41372108 and41602110)the Research Fund for the Doctoral Program of Higher Education of China(grant No.20133718130001)+1 种基金the Qingdao Postdoctoral Applied Research Project(grant No.2015193)the SDUST Research Fund(grant No.2015TDJH101)
文摘Objective The NE China is located in the eastern segment of the Central Asian Orogenic Belt（CAOB）,which is a large accretionary orogen between the Siberian Craton and the North China Craton（NCC）.Many researches have discussed about the evolution of the Paleo-Asian Ocean（PAO）in the eastern CAOB.However,
