Effects of anisotropy and fabric development on convection in ice Ih mantles

We study the effects of fabric development on convection in Ice I mantles using a new numerical model. In order to simulate the effect of texture development, we coupled a model for polycrystal deformation that incorporates dislocation creep on basal planes, grain boundary sliding, and diffusion creep with a macroscopic mantle flow model. Texture is tracked on tracer particles and allowed to evolve. Coupling between the microscopic and macroscopic models is two-way: macroscopic strain induces changes in crystallographic preferred orientation (CPO) on microscopic scales, and the anisotropic response of polycrystalline ice affects the macroscopic rheological behavior. We present results from two-dimensional simulations in which we allow texture to evolve and contrast these results with simulations in which ice remains isotropic. Surface features described as pits and domes on Europa may be manifestations of convection in Europa's predominantly water-ice mantle. We compare our model results with observed topography with the aim of understanding whether fabric development can explain discrepancies between the observed topography and predictions from previous models.