Northeast China is a unique place to study intra-plate volcanism. We analyzed P-wave receiver function data recorded by 111 permanent broadband seismic stations in Northeast China. The results show that the crustal th...Northeast China is a unique place to study intra-plate volcanism. We analyzed P-wave receiver function data recorded by 111 permanent broadband seismic stations in Northeast China. The results show that the crustal thickness varies from 27.9 km beneath the eastern flank of the Songliao Basin to 40.7 km beneath the Great Xing'an Range region. The large depth variations of the Moho can be largely but not completely explained by surface topography. The residual Moho depth calculated based on the Airy's isostasy model indicates that the Moho is dynamically uplifted by 〈3 km beneath the eastern flank of the Songliao Basin and the Changbaishan region. We suggest that a mantle upwelling, which has been proposed by several recent seismic studies, might have caused the uplift.展开更多
Deep hot mantle upwelling is widely revealed around the Qiongdongnan Basin on the northwestern South China Sea margin. However, when and how it influenced the hyper-extended basin is unclear.To resolve these issues, a...Deep hot mantle upwelling is widely revealed around the Qiongdongnan Basin on the northwestern South China Sea margin. However, when and how it influenced the hyper-extended basin is unclear.To resolve these issues, a detailed analysis of the Cenozoic time-varying residual subsidence derived by subtracting the predicted subsidence from the backstripped subsidence was performed along a new seismic reflection line in the western Qiongdongnan Basin. For the first time, a method is proposed to calculate the time-varying strain rates constrained by the faults growth rates, on basis of which, the predicted basement subsidence is obtained with a basin-and lithosphere-scale coupled finite extension model, and the backstripped subsidence is accurately recovered with a modified technique of backstripping to eliminate the effects of later episodes of rifting on earlier sediment thickness. Results show no residual subsidence in 45–28.4 Ma. But after 28.4 Ma, negative residual subsidence occurred, reached and remained ca. -1000 m during 23–11.6 Ma, and reduced dramatically after 11.6 Ma. In the syn-rift period(45–23 Ma), the residual subsidence is ca. -1000 m, however in the post-rift period(23–0 Ma),it is positive of ca. 300 to 1300 m increasing southeastwards. These results suggest that the syn-rift subsidence deficit commenced at 28.4 Ma, while the post-rift excess subsidence occurred after 11.6 Ma.Combined with previous studies, it is inferred that the opposite residual subsidence in the syn-and post-rift periods with similar large wavelengths(>10^(2) km) and km-scale amplitudes are the results of transient dynamic topography induced by deep mantle upwelling beneath the central QDNB, which started to influence the basin at ca. 28.4 Ma, continued into the Middle Miocene, and decayed at ca.11.6 Ma. The initial mantle upwelling with significant dynamic uplift had precipitated considerable continental extension and faulting in the Late Oligocene(28.4–23 Ma). After ca. 11.6 Ma, strong mantle upwelling probably occurred beneath the Leizhou–Hainan area to form vast basaltic lava flow.展开更多
Intraplate processes,such as continental surface uplift and intraplate volcanism,are enigmatic and the underlying mechanisms responsible are not fully understood.Central Mongolia is an ideal natural laboratory for stu...Intraplate processes,such as continental surface uplift and intraplate volcanism,are enigmatic and the underlying mechanisms responsible are not fully understood.Central Mongolia is an ideal natural laboratory for studying such processes because of its location in the continental interior far from tectonic plate boundaries.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
? Tertiary basins distributed mainly in two zones in the CircumPacific region of China, which includes a rift basin zone in continental area and a continental margin basin zone in offshore area of west Pacific Ocea...? Tertiary basins distributed mainly in two zones in the CircumPacific region of China, which includes a rift basin zone in continental area and a continental margin basin zone in offshore area of west Pacific Ocean. Extensional regime dominated the evolution processes of the basins, and in many cases the extensional process was accompanied by dextral strikeslip movement. Mantle upwelling or plumes have been found beneath the rift zone and the marginal sea basins by geophysical and volcanic petrology research. Based upon the regional studies, the basin formation, lithosphere thinning and mantle upwelling may be caused by the superimposed effect of three processes: (1) subduction of Pacific plate, (2) subduction of IndiaAustralia plate which is the main controlling factor for the opening of the South China Sea and (3) collision of India with Eurasia.展开更多
Geophysical studies point to a complex tectonic and geodynamic evolution of the Alboran Basin and Gulf of Cadiz. Tomograpbic images show strong seismic waves velocity contrasts in the upper mantle. The high velocity a...Geophysical studies point to a complex tectonic and geodynamic evolution of the Alboran Basin and Gulf of Cadiz. Tomograpbic images show strong seismic waves velocity contrasts in the upper mantle. The high velocity anomaly beneath the Alboran Sea recovered by a number of studies is now a well estab- lished feature. Several geodynamic reconstructions have been proposed also on the base of these images. We present and elaborate on restllts coming from a recent tomography study which concentrates on both the Alboran and the adjacent Atlantic region. These new results, while they confirm the existence of the fast anomaly below the Alboran region, also show interesting features of the lithosphere-asthenosphere system below the Atlantic. A high velocity body is imaged roughly below the Horseshoe Abyssal plain down to sub-lithospheric depths. This feature suggests either a possible initiation or relic subduction. Pronounced low velocity anomalies pervade the upper mantle below the Atlantic region and separate the lithospheres of the two regions. We also notice a strong change of the upper mantle velocity structure going from south to north across the Gorringe Bank. This variation in structure could be related to the different evolution in the opening of the central and northern Atlantic oceans.展开更多
文摘Northeast China is a unique place to study intra-plate volcanism. We analyzed P-wave receiver function data recorded by 111 permanent broadband seismic stations in Northeast China. The results show that the crustal thickness varies from 27.9 km beneath the eastern flank of the Songliao Basin to 40.7 km beneath the Great Xing'an Range region. The large depth variations of the Moho can be largely but not completely explained by surface topography. The residual Moho depth calculated based on the Airy's isostasy model indicates that the Moho is dynamically uplifted by 〈3 km beneath the eastern flank of the Songliao Basin and the Changbaishan region. We suggest that a mantle upwelling, which has been proposed by several recent seismic studies, might have caused the uplift.
基金This research was supported by the Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology(NO.MMRKF201805)by CAS Youth Innovation Promotion Association+5 种基金by Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0205)by Guangzhou Municipal Science and technology program(NO.201904010285)by K.C.Wong Education Foundation(NO.GJTD2018-13)by Key Laboratory of Marine Mineral Resources,Ministry of Natural Resources(NO.KLMMR-2018-B-06)by Innovation Academy of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences(NO.ISEE2018PY02)by National Natural Science Foundation of China(NO.42076077)。
文摘Deep hot mantle upwelling is widely revealed around the Qiongdongnan Basin on the northwestern South China Sea margin. However, when and how it influenced the hyper-extended basin is unclear.To resolve these issues, a detailed analysis of the Cenozoic time-varying residual subsidence derived by subtracting the predicted subsidence from the backstripped subsidence was performed along a new seismic reflection line in the western Qiongdongnan Basin. For the first time, a method is proposed to calculate the time-varying strain rates constrained by the faults growth rates, on basis of which, the predicted basement subsidence is obtained with a basin-and lithosphere-scale coupled finite extension model, and the backstripped subsidence is accurately recovered with a modified technique of backstripping to eliminate the effects of later episodes of rifting on earlier sediment thickness. Results show no residual subsidence in 45–28.4 Ma. But after 28.4 Ma, negative residual subsidence occurred, reached and remained ca. -1000 m during 23–11.6 Ma, and reduced dramatically after 11.6 Ma. In the syn-rift period(45–23 Ma), the residual subsidence is ca. -1000 m, however in the post-rift period(23–0 Ma),it is positive of ca. 300 to 1300 m increasing southeastwards. These results suggest that the syn-rift subsidence deficit commenced at 28.4 Ma, while the post-rift excess subsidence occurred after 11.6 Ma.Combined with previous studies, it is inferred that the opposite residual subsidence in the syn-and post-rift periods with similar large wavelengths(>10^(2) km) and km-scale amplitudes are the results of transient dynamic topography induced by deep mantle upwelling beneath the central QDNB, which started to influence the basin at ca. 28.4 Ma, continued into the Middle Miocene, and decayed at ca.11.6 Ma. The initial mantle upwelling with significant dynamic uplift had precipitated considerable continental extension and faulting in the Late Oligocene(28.4–23 Ma). After ca. 11.6 Ma, strong mantle upwelling probably occurred beneath the Leizhou–Hainan area to form vast basaltic lava flow.
基金part of the research project"Crustmantle interactions beneath the Hangai Mountains in western Mongolia"the financial support of the DFG and the SNF,awarded through the DACH program
文摘Intraplate processes,such as continental surface uplift and intraplate volcanism,are enigmatic and the underlying mechanisms responsible are not fully understood.Central Mongolia is an ideal natural laboratory for studying such processes because of its location in the continental interior far from tectonic plate boundaries.
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.
文摘? Tertiary basins distributed mainly in two zones in the CircumPacific region of China, which includes a rift basin zone in continental area and a continental margin basin zone in offshore area of west Pacific Ocean. Extensional regime dominated the evolution processes of the basins, and in many cases the extensional process was accompanied by dextral strikeslip movement. Mantle upwelling or plumes have been found beneath the rift zone and the marginal sea basins by geophysical and volcanic petrology research. Based upon the regional studies, the basin formation, lithosphere thinning and mantle upwelling may be caused by the superimposed effect of three processes: (1) subduction of Pacific plate, (2) subduction of IndiaAustralia plate which is the main controlling factor for the opening of the South China Sea and (3) collision of India with Eurasia.
文摘Geophysical studies point to a complex tectonic and geodynamic evolution of the Alboran Basin and Gulf of Cadiz. Tomograpbic images show strong seismic waves velocity contrasts in the upper mantle. The high velocity anomaly beneath the Alboran Sea recovered by a number of studies is now a well estab- lished feature. Several geodynamic reconstructions have been proposed also on the base of these images. We present and elaborate on restllts coming from a recent tomography study which concentrates on both the Alboran and the adjacent Atlantic region. These new results, while they confirm the existence of the fast anomaly below the Alboran region, also show interesting features of the lithosphere-asthenosphere system below the Atlantic. A high velocity body is imaged roughly below the Horseshoe Abyssal plain down to sub-lithospheric depths. This feature suggests either a possible initiation or relic subduction. Pronounced low velocity anomalies pervade the upper mantle below the Atlantic region and separate the lithospheres of the two regions. We also notice a strong change of the upper mantle velocity structure going from south to north across the Gorringe Bank. This variation in structure could be related to the different evolution in the opening of the central and northern Atlantic oceans.