Evaluating the Influence of Plate Boundary Friction and Mantle Viscosity on Plate Velocities.

Osei Tutu, A., Sobolev, S. V., Steinberger, B., Popov, A. A. and Rogozhina, I. (2018) Evaluating the Influence of Plate Boundary Friction and Mantle Viscosity on Plate Velocities. Open Access Geochemistry Geophysics Geosystems, 19 (3). pp. 642-666. DOI 10.1002/2017GC007112.

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Abstract

Lithospheric plates move over the low‐viscosity asthenosphere balancing several forces, which generate plate motions. We use a global 3‐D lithosphere‐asthenosphere model (SLIM3D) with visco‐elasto‐plastic rheology coupled to a spectral model of mantle flow at 300 km depth to quantify the influence of intra‐plate friction and asthenospheric viscosity on plate velocities. We account for the brittle‐ductile deformation at plate boundaries (yield stress) using a plate boundary friction coefficient to predict the present‐day plate motion and net rotation of the lithospheric plates. Previous modeling studies have suggested that small friction coefficients ( urn:x-wiley:15252027:media:ggge21498:ggge21498-math-0001, yield stress urn:x-wiley:15252027:media:ggge21498:ggge21498-math-0002 MPa) can lead to plate tectonics in models of mantle convection. Here we show that in order to match the observed present‐day plate motion and net rotation, the frictional parameter must be less than 0.05. We obtain a good fit with the magnitude and orientation of the observed plate velocities (NUVEL‐1A) in a no‐net‐rotation (NNR) reference frame with urn:x-wiley:15252027:media:ggge21498:ggge21498-math-0003 and a minimum asthenosphere viscosity of urn:x-wiley:15252027:media:ggge21498:ggge21498-math-0004 Pas to 1020 Pas. Our estimates of net rotation (NR) of the lithosphere suggest that amplitudes urn:x-wiley:15252027:media:ggge21498:ggge21498-math-0005 ( urn:x-wiley:15252027:media:ggge21498:ggge21498-math-0006/Ma), similar to most observation‐based estimates, can be obtained with asthenosphere viscosity cutoff values of urn:x-wiley:15252027:media:ggge21498:ggge21498-math-0007 Pas to urn:x-wiley:15252027:media:ggge21498:ggge21498-math-0008 Pas and friction coefficients urn:x-wiley:15252027:media:ggge21498:ggge21498-math-0009.

Document Type: Article
Keywords: lithosphere‐asthenosphere coupling with mantle convection; upper mantle rheology; lithosphere net rotation; plate motion; plate boundary friction; water content in asthenosphere;
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2017GC007112
ISSN: 1525-2027
Projects: PalMod in-kind
Date Deposited: 12 Sep 2018 13:02
Last Modified: 01 Feb 2019 15:03
URI: http://oceanrep.geomar.de/id/eprint/44262

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