Texturing of the upper mantle during convection

摘要

Convection of rocks in the Earth's mantle I:ives rise to crystallographic texture of the constituent mineral, olivine. In this paper, we present simulations of texturing of olivine as it flows through a two-dimensional, buoyancy-driven convection cell. The simulations utilize a finite-element formulation for coupled heat transfer and viscoplastic flow, together with polycrystal plasticity, to evaluate the deformation of rocks within the convection cell and the consequent texture evolution in the upper mantle. From the computed texture field, which varies considerably over the cell, the seismic velocity distribution is evaluated. Seismic velocity variations are presented and discussed in the context of earthquake travel time observations and tomographic maps. [References: 68]