This is an interesting problem but this paper has a few fundamental flaws. 1) The background on the current thinking of the Fe-isotope contents of the bulk silicate earth is out of date. 2) If the mantle were hotter, which it surely was in the past, pos

Andrew Matzen (Caltech) to Petrology Reading Group

This is an interesting problem but this paper has a few fundamental flaws. 1) The background on the current thinking of the Fe-isotope contents of the bulk silicate earth is out of date. 2) If the mantle were hotter, which it surely was in the past, post-perovskite would not be stable at the core-mantle boundary (does perovskite display a similar behavior?). Lastly (3) the mantle is not in equilibrium with the core at the CMB (Ni and Co partitioning).
The idea behind the paper is neat (using the partial density of states to predict isotope fractionation) unfortunately it left the reading group wanting more.

Equilibrium Iron Isotope Fractionation at Core-Mantle Boundary Conditions. Polyakov V. B. (2009) Science.

November 20, 2009