The Mussau Trench between the Caroline Plate and Pacific Plate offers an important geological window into the initial subduction process.This study presents a detailed characterization of local-scale tectonic deformat...The Mussau Trench between the Caroline Plate and Pacific Plate offers an important geological window into the initial subduction process.This study presents a detailed characterization of local-scale tectonic deformation along the Mussau Trench using high-resolution multibeam bathymetry and 2D multi-channel seismic reflection profiles.The bathymetric data processed with illumination gradient analysis and low-pass filtering reveal more structural details,including distinct linear deformation features,variations in accretionary wedge morphology,and notable indentation structures within the overriding Mussau Ridge to the east of the Mussau Trench.These features are related to transform faults,stress localization and subduction termination dynamics.Furthermore,our analysis demonstrates pronounced longitudinal segmentation in tectonic deformation along the Mussau Trench,divided by the newly identified indentation features.Additionally,the local deformation patterns supports the interpretation that the intra-ridge valley within the Mussau Ridge represents the boundary between the Caroline Plate and Pacific Plate.The convergent deformation between the two plates uplifted the plate boundaries in conjunction and created an intra-ridge valley,in which a set of subparallel linear troughs developed.Based on these observations,we further propose future deep-sea drilling targets at key deformation locations,which can help constrain the tectonic evolution model of subduction initiation and termination.展开更多
New seismic imaging from the Mussau Trench confirms that,under horizontal compression on an oceanic plate boundary,it is within the young and weak oceanic plate that a trench will develop,and it is the young plate,not...New seismic imaging from the Mussau Trench confirms that,under horizontal compression on an oceanic plate boundary,it is within the young and weak oceanic plate that a trench will develop,and it is the young plate,not so long after its birth,that starts to subduct toward the old plate.The Mesozoic Pacific Plate cannot easily bend,under the joint horizontal compression and vertical gravity pull,even with a pre-existing weak zone in place and with a large age offset across the plate boundary.The bending of the Caroline Plate near the northern end of the Mussau Trench started only after a long-time span of trench migration,and/or after a prolonged transition from initial compression to trench development.Highly contrasting trench deformation and sedimentary accretion between two parallel seismic sections support an evident migration of underthrusting or significant longitudinal heterogeneity along the trench.The swift transition from underthrusting to non-thrusting can be explained by a counter-clockwise rotation of the Caroline Plate.That miniature accretionary wedges develop even before the subduction initiates imply strong compression and uplifting before the underthrusting can kick-start.Rotation of the Caroline Plate have been halted as the Mussau Trench is seismically rather quiet and the Lyra Trough to the east shows relaxational extension.展开更多
基金The National Key Research and Development Program of China under contract No.2023YFF0803404the National Natural Science Foundation of China under contract Nos 91858213 and 4257060245+1 种基金the Hainan Provincial Natural Science Foundation under contract No.421CXTD441the Zhoushan Science and Technology Bureau Project under contract No.2020C81058.
文摘The Mussau Trench between the Caroline Plate and Pacific Plate offers an important geological window into the initial subduction process.This study presents a detailed characterization of local-scale tectonic deformation along the Mussau Trench using high-resolution multibeam bathymetry and 2D multi-channel seismic reflection profiles.The bathymetric data processed with illumination gradient analysis and low-pass filtering reveal more structural details,including distinct linear deformation features,variations in accretionary wedge morphology,and notable indentation structures within the overriding Mussau Ridge to the east of the Mussau Trench.These features are related to transform faults,stress localization and subduction termination dynamics.Furthermore,our analysis demonstrates pronounced longitudinal segmentation in tectonic deformation along the Mussau Trench,divided by the newly identified indentation features.Additionally,the local deformation patterns supports the interpretation that the intra-ridge valley within the Mussau Ridge represents the boundary between the Caroline Plate and Pacific Plate.The convergent deformation between the two plates uplifted the plate boundaries in conjunction and created an intra-ridge valley,in which a set of subparallel linear troughs developed.Based on these observations,we further propose future deep-sea drilling targets at key deformation locations,which can help constrain the tectonic evolution model of subduction initiation and termination.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFF0803400,2023YFF0803404)the National Natural Science Foundation of China(Grant No.91858213)+2 种基金the Natural Science Foundation of Hainan Province(Grant No.421CXTD441)the Zhoushan Science and Technology Bureau Program(Grant No.2020C81058)the Shiptime Sharing Project from National Natural Science Foundation of China(Grant No.41949581)。
文摘New seismic imaging from the Mussau Trench confirms that,under horizontal compression on an oceanic plate boundary,it is within the young and weak oceanic plate that a trench will develop,and it is the young plate,not so long after its birth,that starts to subduct toward the old plate.The Mesozoic Pacific Plate cannot easily bend,under the joint horizontal compression and vertical gravity pull,even with a pre-existing weak zone in place and with a large age offset across the plate boundary.The bending of the Caroline Plate near the northern end of the Mussau Trench started only after a long-time span of trench migration,and/or after a prolonged transition from initial compression to trench development.Highly contrasting trench deformation and sedimentary accretion between two parallel seismic sections support an evident migration of underthrusting or significant longitudinal heterogeneity along the trench.The swift transition from underthrusting to non-thrusting can be explained by a counter-clockwise rotation of the Caroline Plate.That miniature accretionary wedges develop even before the subduction initiates imply strong compression and uplifting before the underthrusting can kick-start.Rotation of the Caroline Plate have been halted as the Mussau Trench is seismically rather quiet and the Lyra Trough to the east shows relaxational extension.
