The study of back-arc sedimentary basins is key to understanding oceanic and continental geodynamic processes and mechanisms.The East China Sea Shelf Basin(ECSSB),a back-arc sedimentary basin in a continent-ocean tran...The study of back-arc sedimentary basins is key to understanding oceanic and continental geodynamic processes and mechanisms.The East China Sea Shelf Basin(ECSSB),a back-arc sedimentary basin in a continent-ocean transition zone of the western Pacific Ocean,exhibits remarkable differences in terms of the tectonic deformation characteristics of the basin and the evolutionary features of its sags.These features have led to varied understandings of deep dynamic mechanisms driving the evolution of the basin.In this study,which is based on a detailed interpretation of two-dimensional multichannel seismic data from the ECSSB,the tectonic deformation of the basin is analyzed and the tectonic evolutionary process of the basin is reconstructed.The above research work combines plate convergence processes and deep crust-mantle interactions to explore the controlling factors and deep dynamic mechanisms of the tectonic deformation in the ECSSB.The results of this study indicate that there are significant differences in tectonic deformation between the southern and northern parts of the basin and that the deformation is characterized by eastward migration.Deep crust-mantle interactions are coupled with the development of these differences.The tectonic deformation of the ECSSB is driven by the interactions of the paleo-Pacific,Pacific,Indian,and Philippine Sea Plates with the Eurasian Plate,which have shaped the tectonic pattern of the ECSSB,resulting in east-west zoning,north-south blocking,and pronounced spatiotemporal variability in tectonic deformation.This research provides new insights into the differential development of sags within the ECSSB and provides an important reference for studying back-arc sedimentary basins.展开更多
In this paper, two sets of gravity and magnetic data were used to study the tectonics of the southern East China Sea and Ryukyu trench-arc system： one data set was from the ＇Geological-geophysical map series of Chin...In this paper, two sets of gravity and magnetic data were used to study the tectonics of the southern East China Sea and Ryukyu trench-arc system： one data set was from the ＇Geological-geophysical map series of China Seas and adjacent areas＇ database and the other was newly collected by R/VKexue Ⅲ in 2011. Magnetic and gravity data were reorganized and processed using the software MMDP, MGDP and RGIS. In addition to the description of the anomaly patterns in different areas, deep and shallow structure studies were performed by using several kinds of calculation, including a spectrum analysis, upward-continuation of the Bouguer anomaly and horizontal derivatives of the total-field magnetic anomaly. The depth of the Moho and magnetic basement were calculated. Based on the above work, several controversial tectonic problems were discussed. Compared to the shelf area and Ryukyu Arc, the Okinawa Trough has an obviously thinned crust, with the thinnest area having thickness less than 14km in the southern part. The Taiwan-Sinzi belt, which terminates to the south by the NW-SE trending Miyako fault belt, contains the relic volcanic arc formed by the splitting of the paleo Ryukyu volcanic arc as a result of the opening of the Okinawa Trough. As an important tectonic boundary, the strike-slip type Miyako fault belt extends northwestward into the shelf area and consists of several discontinuous segments. A forearc terrace composed of an exotic terrane collided with the Ryukyu Arc following the subduction of the Philippine Sea Plate. Mesozoic strata of varying thicknesses exist beneath the Cenozoic strata in the shelf basin and significantly influence the magnetic pattern of this area. The gravity and magnetic data support the existence of a Great East China Sea, which suggests that the entire southern East China Sea shelf area was a basin in the Mesozoic without alternatively arranged uplifts and depressions, and might have extended southwestward and connected with the northern South China Sea shelf basin.展开更多
基金the Laoshan Laboratory(No.LSKJ202203401)the Geological Survey Projects of the China Geological Survey(Nos.DD20221723,DD20243116)+2 种基金the Natural Science Foundation of Shandong Province(No.ZR2023MD047)the Major Basic Research Project of Shandong Province(No.ZR2021ZD09)the National Natural Science Foundation of China(No.42476077)。
文摘The study of back-arc sedimentary basins is key to understanding oceanic and continental geodynamic processes and mechanisms.The East China Sea Shelf Basin(ECSSB),a back-arc sedimentary basin in a continent-ocean transition zone of the western Pacific Ocean,exhibits remarkable differences in terms of the tectonic deformation characteristics of the basin and the evolutionary features of its sags.These features have led to varied understandings of deep dynamic mechanisms driving the evolution of the basin.In this study,which is based on a detailed interpretation of two-dimensional multichannel seismic data from the ECSSB,the tectonic deformation of the basin is analyzed and the tectonic evolutionary process of the basin is reconstructed.The above research work combines plate convergence processes and deep crust-mantle interactions to explore the controlling factors and deep dynamic mechanisms of the tectonic deformation in the ECSSB.The results of this study indicate that there are significant differences in tectonic deformation between the southern and northern parts of the basin and that the deformation is characterized by eastward migration.Deep crust-mantle interactions are coupled with the development of these differences.The tectonic deformation of the ECSSB is driven by the interactions of the paleo-Pacific,Pacific,Indian,and Philippine Sea Plates with the Eurasian Plate,which have shaped the tectonic pattern of the ECSSB,resulting in east-west zoning,north-south blocking,and pronounced spatiotemporal variability in tectonic deformation.This research provides new insights into the differential development of sags within the ECSSB and provides an important reference for studying back-arc sedimentary basins.
基金funded by the National Key Basic Research Program of China (973 ProgramGrant No.2013CB429701)National Natural Science Foundations of China (Grant Nos.41206050 and 41202081)
文摘In this paper, two sets of gravity and magnetic data were used to study the tectonics of the southern East China Sea and Ryukyu trench-arc system： one data set was from the ＇Geological-geophysical map series of China Seas and adjacent areas＇ database and the other was newly collected by R/VKexue Ⅲ in 2011. Magnetic and gravity data were reorganized and processed using the software MMDP, MGDP and RGIS. In addition to the description of the anomaly patterns in different areas, deep and shallow structure studies were performed by using several kinds of calculation, including a spectrum analysis, upward-continuation of the Bouguer anomaly and horizontal derivatives of the total-field magnetic anomaly. The depth of the Moho and magnetic basement were calculated. Based on the above work, several controversial tectonic problems were discussed. Compared to the shelf area and Ryukyu Arc, the Okinawa Trough has an obviously thinned crust, with the thinnest area having thickness less than 14km in the southern part. The Taiwan-Sinzi belt, which terminates to the south by the NW-SE trending Miyako fault belt, contains the relic volcanic arc formed by the splitting of the paleo Ryukyu volcanic arc as a result of the opening of the Okinawa Trough. As an important tectonic boundary, the strike-slip type Miyako fault belt extends northwestward into the shelf area and consists of several discontinuous segments. A forearc terrace composed of an exotic terrane collided with the Ryukyu Arc following the subduction of the Philippine Sea Plate. Mesozoic strata of varying thicknesses exist beneath the Cenozoic strata in the shelf basin and significantly influence the magnetic pattern of this area. The gravity and magnetic data support the existence of a Great East China Sea, which suggests that the entire southern East China Sea shelf area was a basin in the Mesozoic without alternatively arranged uplifts and depressions, and might have extended southwestward and connected with the northern South China Sea shelf basin.
