Mantle phase transitions and layered chaotic convection

Abstract

We report preliminary results from a sequence of very high resolution simulations of the mantle convection process based upon an axisymmetric anelastically compressible spherical model with both Olivine‐Spinel and Spinel‐post Spinel phase transitions. Our analyses strongly suggest that at Earth‐like Rayleigh numbers near 10 7 the circulation may be quite strongly layered, although a very long timescale transient exists that is characterized by brief excursions into the whole mantle state. We suggest the use of a new diagnostic tool that may be employed to determine whether or not the layered state is characteristic of the present day earth.