On the role of anisotropic viscosity for plate-scale flow

We study the role of partial melt-or lattice fabric-induced, viscous anisotropy for lithosphere-asthenosphere interactions using mantle flow models. Mechanical anisotropy has only a moderate influence on plate-scale flow and global geoid predictions for the cases considered, and anisotropic weakening effects are similar to those due to effective, isotropic viscosity reduction. While anisotropy modifies details of mantle flow and may be relevant for time-dependent scenarios, it may be safely ignored for a range of other studies. These findings increase our confidence in previous isotropic modeling. They also imply that melt-rich layers may be a dynamically valid explanation for the lithosphere-asthenosphere boundary, as far as our anisotropic models are applicable. Citation: Becker, T. W., and H. Kawakatsu (2011), On the role of anisotropic viscosity for plate-scale flow, Geophys. Res. Lett., 38, L17307, doi:10.1029/2011GL048584.