ODFTEX: a continuum model for texture evolution with dynamic recrystallization

SUMMARY: We present a new method, ODFTEX, for calculating evolving crystal preferred orientation (CPO) in deforming aggregates of olivine plus orthopyroxene undergoing dynamic recrystallization. The model is based on a continuum description of texture in terms of the orientation distribution function (ODF), which satisfies an evolution equation that we solve numerically. The model thus delivers the ODF directly, rather than a collection of grain orientations like most alternative models. Recrystallization is represented by a source term in the evolution equation, defined in such a way that crystals poorly oriented for slip recrystallize most rapidly. The model has only a single free parameter, the recrystallization rate, which we calibrate against a laboratory experiment on an olivine aggregate deformed in simple shear. We illustrate the predictive power of ODFTEX by using it to calculate evolving CPO along pathlines in a 2-D convective flow and a 3-D subduction zone flow. ODFTEX is computationally about six to seven times faster than the D-Rex model of E. Kaminski et al.