An effective parameterization of texture-induced viscous anisotropy in orthotropic materials with application for modeling geodynamical flows

In this article, we describe the mathematical formulation and numerical implementation of an effective parametrization viscous anisotropy orthorhombic materials produced by crystallographic preferred orientations (CPO or texture), which can be integrated into 3D geodynamic science codes. Here, approach is applied to characterize texture-induced olivine polycrystals, main constituent Earth's upper mantle. The parameterization based on Hill (1948) orthotropic yield criterion. coefficients surface are calibrated tests performed using second order Viscoplastic Self-consistent (SO-VPSC) model. was implemented in a thermo-mechanical finite-element code developed model large-scale geodynamical flows, form Maxwell rheology combining isotropic elastic anisotropic non-linear behaviors. validated comparison with results analytical solution SO-VPSC for simple shear axial compression homogeneous material. An application designed examine effect reactivation mantle zones continental plates highlights unexpected couplings between localized deformation controlled variations orientation intensity texture mechanical behavior elasto-viscoplastic overlying crust. Importantly, computational time only increases factor 2-3 respect classic viscoelastic rheology.