Oxygen solubility in Fe-Ni-S alloy at high pressure and implications for the formation and compositions of planetary cores

点击翻译按钮获取中文摘要

The most important fractionation event to affect the geochemistry of the terrestrial planets was their segregation into metallic Fe-rich cores and silicate mantles. Although this process clearly influenced the distribution of siderophile elements between these regions, the conditions under which it took place and the resulting distribution of light elements remain poorly constrained. In the course of this study we aim to develop new models for the geochemical evolution of terrestrial planets during core formation. The solubility of oxygen and sulphur in Fe and Fe-Ni-rich liquid metal will be studied in experiments to pressures of up 25 GPa. Using a thermodynamic model fit to the results of these experiments the geochemical consequences of metal silicate equilibration in realistic magma ocean environments will be explored, partly in collaboration with Prof. U. Hansen/Münster. These models will enable us to understand, for example, whether the core formed progressively as a result of a series of relatively shallow magma oceans during accretion or whether core-mantle equilibration was partly or completely established during melting of the entire mantle.