HR: 17:30h
AN: DI14A-07    [Abstracts]
TI: Continuously closing plates: A new Paleogeographic concept and application to geodynamic models
AU: * Gurnis, M
EM: gurnis@gps.caltech.edu
AF: Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: Turner, M
EM: mturner@gps.caltech.edu
AF: Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: Spasojevic, S
EM: skisin@gps.caltech.edu
AF: Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: Bower, D
EM: danb@gps.caltedh.edu
AF: Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: Liu, L
EM: lijun@gps.caltech.edu
AF: Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, United States
AU: Manea, V
EM: vlab@gps.caltech.edu
AF: Geodynamics Laboratory, Centro de Geociencias - UNAM Campus, Juriquilla, 3001, Mexico
AU: Muller, R D
EM: dietmarmuller@mac.com
AF: School of Geosciences, University of Sydney, Sydney, NSW 2006, Australia
AU: Boyden, J
EM: jboyden@geosci.usyd.edu.au
AF: School of Geosciences, University of Sydney, Sydney, NSW 2006, Australia
AU: Sdrolias, M
EM: marias@geosci.usyd.edu.au
AF: School of Geosciences, University of Sydney, Sydney, NSW 2006, Australia
AU: DiCaprio, L
EM: lydia@gps.caltech.edu
AF: School of Geosciences, University of Sydney, Sydney, NSW 2006, Australia
AB: Global plate tectonic reconstructions are inadequate for geodynamics, either as information to be assimilated into a model or as the basis to map a prediction into the geological record. Published reconstructions are often crudely spaced in time, have large swaths of the surface ambiguously defined, and/or have plate margin evolution inconsistent with plate motions. We have overcome these limitations with the formulation and implementation of a new method to represent plate tectonic reconstructions. Referred to as either "continuously closing" or "dynamically closing" plate polygons, the new method has been implemented using the new plate tectonic modeling package GPlates, global reconstruction have been developed with the method, and then reconstructions have been assimilated into forward and adjoint mantle convection models. Essentially, a plate is defined as a polygon that is made up of a finite set of plate boundaries. Each plate boundary is associated with its own set of finite rotations in an absolute reference system. These plate boundaries are continuously rotated and an algorithm finds the intersection of adjacent plate boundaries. Two adjacent plates always share a boundary. Using this method in GPlates, we have developed several global plate reconstructions from 140 Ma to the present. Since plate closure is continuous in time, reconstructions can exist at any granularity of time. Our present model has been output at 1 Myr time intervals. Subduction zones and their polarity are continuously tracked. The present plate reconstructions are self-consistent with a set of oceanic paleo age grids. We will illustrate the use of the new reconstructions in several applications drawn from our recent work: (1) regional subduction models; (2) global models of thermo-chemical convection in the lower mantle; (3) inverse and adjoint models of the descent of the Farallon slab; and (4) instantaneous models of global plate motions.
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 7270 Tomography (6982, 8180)
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
DE: 8157 Plate motions: past (3040)
SC: Study of the Earth's Deep Interior [DI]
MN: 2007 Fall Meeting