The Tibetan Plateau(TP)is the youngest orogenic belt resulting from a continental collision on the Earth.It is a natural laboratory for studying continental dynamics,such as continental convergence,plate subduction,an...The Tibetan Plateau(TP)is the youngest orogenic belt resulting from a continental collision on the Earth.It is a natural laboratory for studying continental dynamics,such as continental convergence,plate subduction,and plateau uplift.Investigating the deep structure of the TP has always been a popular issue in geological research.The Moho is the boundary between the crust and the mantle and therefore plays a crucial role in the Earth’s structure.Parameters such as depth and lateral variation,as well as the fine structure of the crust-mantle interface,reveal the lithospheric dynamics in the TP.Two methods are generally employed to study the Moho surface:seismic detection and gravity inversion.Seismic detection has the characteristic of high precision,but it is limited to a few cross-sectional lines and is quite costly.It is not suitable for and cannot be carried out over a large area of the TP.The Moho depth over a large area can be obtained through gravity inversion,but this method is affected by the nature of gravity data,and the accuracy of the inversion method is lower than that of seismic detection.In this work,a high-precision gravity field model was selected.The Parker-Oldenburg interface inversion method was used,within the constraints of seismic observations,and the Bott iteration method was introduced to enhance the inversion efficiency.The Moho depth in the TP was obtained with high precision,consistent with the seismic detection results.The research results showed that the shape of the Moho in the TP is complex and the variation range is large,reaching 60−80 km.In contrast with the adjacent area,a clear zone of sharp variation appears at the edge of the plateau.In the interior of the TP,the buried depth of the Moho is characterized by two depressions and two uplifts.To the south of the Yarlung Zangbo River,the Moho inclines to the north,and to the north,the Moho depresses downward,which was interpreted as the Indian plate subducting to the north below Tibet.The Moho depression on the north side of the Qiangtang block,reaching 72 km deep,may be a result of the southward subduction of the lithosphere.The Moho uplift of the Qiangtang block has the same strike as the Bangong−Nujiang suture zone,which may indicate that the area is compensated by a low-density and low-velocity mantle.展开更多
Knowing Moho discontinuity undulation is fundamental to understanding mechanisms of lithosphereasthenosphere interaction, extensional tectonism and crustal deformation in volcanic passive margins such as the study are...Knowing Moho discontinuity undulation is fundamental to understanding mechanisms of lithosphereasthenosphere interaction, extensional tectonism and crustal deformation in volcanic passive margins such as the study area, which is located in the southwestern corner of the Arabian Peninsula bounded by the Red Sea and the Gulf of Aden. In this work, a 3D Moho depth model of the study area is constructed for the first time by inverting gravity data from the Earth Gravitational Model(EGM2008) using the ParkerOldenburg algorithm. This model indicates the shallow zone is situated at depths of 20 km to 24 km beneath coastal plains, whereas the deep zone is located below the plateau at depths of 30 km to 35 km and its deepest part coincides mainly with the Dhamar-Rada ’a Quaternary volcanic field. The results also indicate two channels of hot magmatic materials joining both the Sana’a-Amran Quaternary volcanic field and the Late Miocene Jabal An Nar volcanic area with the Dhamar-Rada’a volcanic field. This conclusion is supported by the widespread geothermal activity(of mantle origin) distributed along these channels,isotopic data, and the upper mantle low velocity zones indicated by earlier studies.展开更多
Owing to the strategic significance of national oil and gas resources,their exploration and production must be prioritized in China.Oil and gas resources are closely related to deep crustal structures,and Moho charact...Owing to the strategic significance of national oil and gas resources,their exploration and production must be prioritized in China.Oil and gas resources are closely related to deep crustal structures,and Moho characteristics influence oil and gas distribution.Therefore,it is important to study the relationship between the variation of the Moho surface depth undulation and hydrocarbon basins for the future prediction of their locations.The Moho depth in the study area can be inverted using the Moho depth control information,the Moho gravity anomaly,and the variable density distribution calculated by the infinite plate.Based on these results,the influences of Moho characteristics on petroleum basins were studied.We found that the Moho surface depth undulation deviation and crustal thickness undulation deviation in the hydrocarbon-rich basins are large,and the horizontal gradient deviation of the Moho surface shows a positive linear relationship with oil and gas resources in the basin.The oil-bearing mechanism of the Moho basin is further discussed herein.The Moho uplift area and the slope zone correspond to the distribution of oil and gas fields.The tensile stress produced by the Moho uplift can form tensile fractures or cause tensile fractures on the surface,further developing into a fault or depression basin that receives deposits.The organic matter can become oil and natural gas under suitable chemical and structural conditions.Under the action of groundwater or other dynamic forces,oil and natural gas are gradually transported to the uplift or the buried hill in the depression zone,and oil and gas fields are formed under the condition of good caprock.The research results can provide new insights into the relationship between deep structures and oil and gas basins as well as assist in the strategic planning of oil and gas exploration activities.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the National Natural Science Foundation of China(Grant No.42192535)the Open Fund of Wuhan,Gravitation and Solid Earth Tides,National Observation and Research Station(No.WHYWZ202204)+1 种基金the Strategic Pioneer Science and Technology Special Project of the Chinese Academy of Sciences(Grant No.XDB18010304)the National Natural Science Foundation of China(Grant No.41874096).
文摘The Tibetan Plateau(TP)is the youngest orogenic belt resulting from a continental collision on the Earth.It is a natural laboratory for studying continental dynamics,such as continental convergence,plate subduction,and plateau uplift.Investigating the deep structure of the TP has always been a popular issue in geological research.The Moho is the boundary between the crust and the mantle and therefore plays a crucial role in the Earth’s structure.Parameters such as depth and lateral variation,as well as the fine structure of the crust-mantle interface,reveal the lithospheric dynamics in the TP.Two methods are generally employed to study the Moho surface:seismic detection and gravity inversion.Seismic detection has the characteristic of high precision,but it is limited to a few cross-sectional lines and is quite costly.It is not suitable for and cannot be carried out over a large area of the TP.The Moho depth over a large area can be obtained through gravity inversion,but this method is affected by the nature of gravity data,and the accuracy of the inversion method is lower than that of seismic detection.In this work,a high-precision gravity field model was selected.The Parker-Oldenburg interface inversion method was used,within the constraints of seismic observations,and the Bott iteration method was introduced to enhance the inversion efficiency.The Moho depth in the TP was obtained with high precision,consistent with the seismic detection results.The research results showed that the shape of the Moho in the TP is complex and the variation range is large,reaching 60−80 km.In contrast with the adjacent area,a clear zone of sharp variation appears at the edge of the plateau.In the interior of the TP,the buried depth of the Moho is characterized by two depressions and two uplifts.To the south of the Yarlung Zangbo River,the Moho inclines to the north,and to the north,the Moho depresses downward,which was interpreted as the Indian plate subducting to the north below Tibet.The Moho depression on the north side of the Qiangtang block,reaching 72 km deep,may be a result of the southward subduction of the lithosphere.The Moho uplift of the Qiangtang block has the same strike as the Bangong−Nujiang suture zone,which may indicate that the area is compensated by a low-density and low-velocity mantle.
文摘Knowing Moho discontinuity undulation is fundamental to understanding mechanisms of lithosphereasthenosphere interaction, extensional tectonism and crustal deformation in volcanic passive margins such as the study area, which is located in the southwestern corner of the Arabian Peninsula bounded by the Red Sea and the Gulf of Aden. In this work, a 3D Moho depth model of the study area is constructed for the first time by inverting gravity data from the Earth Gravitational Model(EGM2008) using the ParkerOldenburg algorithm. This model indicates the shallow zone is situated at depths of 20 km to 24 km beneath coastal plains, whereas the deep zone is located below the plateau at depths of 30 km to 35 km and its deepest part coincides mainly with the Dhamar-Rada ’a Quaternary volcanic field. The results also indicate two channels of hot magmatic materials joining both the Sana’a-Amran Quaternary volcanic field and the Late Miocene Jabal An Nar volcanic area with the Dhamar-Rada’a volcanic field. This conclusion is supported by the widespread geothermal activity(of mantle origin) distributed along these channels,isotopic data, and the upper mantle low velocity zones indicated by earlier studies.
基金The Scientific and Technological Project of CNOOC Research Institute Co.,Ltd.,under contract No.CCL2021RCPS0167KQNthe Fundamental Research Fund for the Central Universities,CHD,under contract No.300102261717。
文摘Owing to the strategic significance of national oil and gas resources,their exploration and production must be prioritized in China.Oil and gas resources are closely related to deep crustal structures,and Moho characteristics influence oil and gas distribution.Therefore,it is important to study the relationship between the variation of the Moho surface depth undulation and hydrocarbon basins for the future prediction of their locations.The Moho depth in the study area can be inverted using the Moho depth control information,the Moho gravity anomaly,and the variable density distribution calculated by the infinite plate.Based on these results,the influences of Moho characteristics on petroleum basins were studied.We found that the Moho surface depth undulation deviation and crustal thickness undulation deviation in the hydrocarbon-rich basins are large,and the horizontal gradient deviation of the Moho surface shows a positive linear relationship with oil and gas resources in the basin.The oil-bearing mechanism of the Moho basin is further discussed herein.The Moho uplift area and the slope zone correspond to the distribution of oil and gas fields.The tensile stress produced by the Moho uplift can form tensile fractures or cause tensile fractures on the surface,further developing into a fault or depression basin that receives deposits.The organic matter can become oil and natural gas under suitable chemical and structural conditions.Under the action of groundwater or other dynamic forces,oil and natural gas are gradually transported to the uplift or the buried hill in the depression zone,and oil and gas fields are formed under the condition of good caprock.The research results can provide new insights into the relationship between deep structures and oil and gas basins as well as assist in the strategic planning of oil and gas exploration activities.
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。
