Texturing of the upper mantle during convection

Convection of rocks in the Earth's mantle I:ives rise to crystallographic t exture of the constituent mineral, olivine. In this paper, we present simul ations of texturing of olivine as it flows through a two-dimensional, buoya ncy-driven convection cell. The simulations utilize a finite-element formul ation for coupled heat transfer and viscoplastic flow, together with polycr ystal plasticity, to evaluate the deformation of rocks within the convectio n cell and the consequent texture evolution in the upper mantle. From the c omputed texture field, which varies considerably over the cell, the seismic velocity distribution is evaluated. Seismic velocity variations are presen ted and discussed in the context of earthquake travel time observations and tomographic maps.