HR: 1340h
AN: T33B-0541    [Abstracts]
TI: Relations between plate kinematics, slab geometry and overriding plate deformation in subduction zones: insights from statistical observations and laboratory modelling
AU: * Heuret, A
EM: heuret@dstu.univ-montp2.fr
AF: Laboratoire Dynamique de la lithosphŠre - UMR CNRS-UM2 5573 - ISTEEM, CC60 - place E. Bataillon, Montpellier, 34095 France
AU: Funiciello, F
EM: ffunicie@uniroma3.it
AF: Dip. Scienze Geologiche, Universit… degli Studi ® Roma TRE ¯, Largo S.L.Murialdo 1, Roma, 00146 Italy
AU: Faccenna, C
EM: faccenna@uniroma3.it
AF: Dip. Scienze Geologiche, Universit… degli Studi ® Roma TRE ¯, Largo S.L.Murialdo 1, Roma, 00146 Italy
AU: Lallemand, S
EM: Serge.Lallemand@dstu.univ-montp2.fr
AF: Laboratoire Dynamique de la lithosphŠre - UMR CNRS-UM2 5573 - ISTEEM, CC60 - place E. Bataillon, Montpellier, 34095 France
AB: 3-D laboratory models have been performed in order to investigate the way plates kinematics (subducting and overriding plate absolute motions and the resulting plate convergence rate) influences the geometry of the slab and the overriding plate deformation in subduction zones. In the experiments a viscous plate of silicone (subducting plate) is pushed beneath another plate, which is itself pushed toward or pulled away from the trench (overriding plate), and sinks into a viscous layer of glucose syrup (upper mantle). The subducting and overriding plate velocities explored the variability field of natural subduction plates kinematics. The overriding plate motion exerts a primary role in the control of slab geometries and overriding plate deformation rates. The experiments have revealed two different subduction behaviours: (Style I) the overriding plate moves toward the trench and shortens at high rates, the slab is flat and deflected when reaching the bottom of the box in a forward direction; (Style II) the overriding plates moves away from the trench and shortens at low rates the slab is steep and deflected on the box bottom in a backward direction. To a lesser extent, increasing subducting plate motion is associated to increasing slab dips and overriding plate shortening. Slab geometry and overriding plate deformation are less sensitive to the overall plate convergence rate. These laboratory models behaviours are consistent with statistical analysis performed on natural subduction zones, and enlighten the first order control exerted by the overriding plate absolute motion, on the geometry adopted by the slab and the way the overriding plate deforms.
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 3060 Subduction zone processes (1031, 3613, 8170, 8413)
DE: 8147 Planetary interiors (5430, 5724, 6024)
DE: 8155 Plate motions: general (3040)
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
SC: Tectonophysics [T]
MN: Fall Meeting 2005