Open AccessEvaluating the Influence of Plate Boundary Friction and Mantle Viscosity on Plate Velocities
Author(s) -
Osei Tutu A.,
Sobolev S. V.,
Steinberger B.,
Popov A. A.,
Rogozhina I.
Publication year - 2018
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2017gc007112
Subject(s) - asthenosphere , geology , lithosphere , plate tectonics , mantle convection , mantle (geology) , geophysics , mechanics , seismology , tectonics , physics
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 ( μ < 0.1 , yield stress ∼ 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 μ < 0.05 and a minimum asthenosphere viscosity of ∼ 5 · 10 19Pas to 10 20 Pas. Our estimates of net rotation (NR) of the lithosphere suggest that amplitudes ∼ 0.1 − 0.2 ( ° /Ma), similar to most observation‐based estimates, can be obtained with asthenosphere viscosity cutoff values of ∼ 10 19Pas to 5 · 10 19Pas and friction coefficients μ < 0.05 .