Partitioning of Sulfur and Platinum at Core Formation Conditions.

Abstract:

Measuring the partitioning behavior of highly siderophile elements (HSE) at high pressures and temperatures is important for understanding the mantle's elemental reservoir and the core mantle differentiation process. Low solubility of HSEs in silicate melts and the small size of samples obtained from diamond anvil cell (DAC) experiments have prevented the experimental study of the partitioning of these elements at realistic deep magma ocean conditions. In this study, we present results for metal-silicate partitioning experiments of sulfur and platinum conducted at pressures between 45 and 80 GPa and at temperatures from 3500 to 4200 K. With the nanoSIMS as our main tool for measuring trace element concentrations, we have developed a protocol for studying the partitioning behavior of these elements from samples that underwent equilibration at high pressure and temperatures in a Laser-Heated DAC. The nanoSIMS has the spatial resolution and the required sensitivity to measure the low concentration of some HSEs in the quenched silicate glass. The results of this study will help to refine current core-mantle differentiation models. Furthermore they add constraints to the contribution of the late veneer to the mantle's elemental abundances.