TY  - JOUR
A1  - Tutu, Anthony Osei
A1  - Sobolev, Stephan Vladimir
A1  - Steinberger, Bernhard
A1  - Popov, A. A.
A1  - Rogozhina, Irina
T1  - Evaluating the Influence of Plate Boundary Friction and Mantle Viscosity on Plate Velocities
T2  - Geochemistry, geophysics, geosystems
N2  - 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 (mu < 0.1, yield stress similar to 100 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 mu < 0.05 and a minimum asthenosphere viscosity of similar to 5 . 10(19) Pas to 10(20) Pas. Our estimates of net rotation (NR) of the lith-osphere suggest that amplitudes similar to 0.1-0.2 (degrees/Ma), similar to most observation-based estimates, can be obtained with asthenosphere viscosity cutoff values of similar to 10(19) Pas to 5 . 10(19) Pas and friction coefficients mu < 0.05.
Y1  - 2018
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/53408
SN  - 1525-2027
VL  - 19
IS  - 3
SP  - 642
EP  - 666
PB  - American Geophysical Union
CY  - Washington
ER  -