Suzanna Van de Lagemaat - Academia.edu (original) (raw)
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Papers by Suzanna Van de Lagemaat
Tectonics, 2018
Tectonic plates subducting at trenches having strikes oblique to the absolute subducting plate m... more Tectonic plates subducting at trenches having strikes oblique to the absolute subducting plate
motion undergo trench-parallel slab motion through the mantle, recently defined as a form of “slab
dragging.” We investigate here long-term slab-dragging components of the Tonga-Kermadec subduction
system driven by absolute Pacific plate motion. To this end we develop a kinematic restoration of
Tonga-Kermadec Trench motion placed in a mantle reference frame and compare it to tomographically
imaged slabs in the mantle. Estimating Tonga-Kermadec subduction initiation is challenging because
another (New Caledonia) subduction zone existed during the Paleogene between the Australia and Pacific
plates. We test partitioning of plate convergence across the Paleogene New Caledonia and Tonga-Kermadec
subduction zones against resulting mantle structure and show that most, if not all, Tonga-Kermadec
subduction occurred after ca. 30 Ma. Since then, Tonga-Kermadec subduction has accommodated 1,700 to
3,500 km of subduction along the southern and northern ends of the trench, respectively. When placed
in a mantle reference frame, the predominantly westward directed subduction evolved while the
Tonga-Kermadec Trench underwent ~1,200 km of northward absolute motion. We infer that the entire
Tonga-Kermadec slab was laterally transported through the mantle over 1,200 km. Such slab dragging by the
Pacific plate may explain observed deep-slab deformation and may also have significant effects on surface
tectonics, both resulting from the resistance to slab dragging by the viscous mantle.
Tectonics, 2018
Tectonic plates subducting at trenches having strikes oblique to the absolute subducting plate m... more Tectonic plates subducting at trenches having strikes oblique to the absolute subducting plate
motion undergo trench-parallel slab motion through the mantle, recently defined as a form of “slab
dragging.” We investigate here long-term slab-dragging components of the Tonga-Kermadec subduction
system driven by absolute Pacific plate motion. To this end we develop a kinematic restoration of
Tonga-Kermadec Trench motion placed in a mantle reference frame and compare it to tomographically
imaged slabs in the mantle. Estimating Tonga-Kermadec subduction initiation is challenging because
another (New Caledonia) subduction zone existed during the Paleogene between the Australia and Pacific
plates. We test partitioning of plate convergence across the Paleogene New Caledonia and Tonga-Kermadec
subduction zones against resulting mantle structure and show that most, if not all, Tonga-Kermadec
subduction occurred after ca. 30 Ma. Since then, Tonga-Kermadec subduction has accommodated 1,700 to
3,500 km of subduction along the southern and northern ends of the trench, respectively. When placed
in a mantle reference frame, the predominantly westward directed subduction evolved while the
Tonga-Kermadec Trench underwent ~1,200 km of northward absolute motion. We infer that the entire
Tonga-Kermadec slab was laterally transported through the mantle over 1,200 km. Such slab dragging by the
Pacific plate may explain observed deep-slab deformation and may also have significant effects on surface
tectonics, both resulting from the resistance to slab dragging by the viscous mantle.