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.
