[S-IT31] Planetary cores: Structure, formation, and evolution

[SIT31-P03] Metal-silicate partitioning of carbon at the core formation

*Yutaro Tsutsumi¹, Naoya Sakamoto², Kei Hirose³, Shunpei Yokoo¹, Shoh Tagawa⁴, Hisayoshi Yurimoto⁵ (1.The University of Tokyo, 2.Creative Research Institution, Hokkaido University, 3.Earth-Life Science Institute, Tokyo Institute of Technology, 4.Department of Earth and Planetary Science, The University of Tokyo, 5.Department of Natural History Sciences, Hokkaido University)

Keywords:Outer core, Light elements, Melting experiments, Carbon, Hydrogen

Carbon has been considered to be one of the possible major light elements in the Earth’s core. While carbon is known to be strongly siderophile (iron-loving) at relatively low pressures, its metal-silicate partitioning under high pressure and temperature (P-T) conditions, typical for those of core segregation from silicate (~50 GPa, 3500 K), has been least examined yet. Here we performed melting experiments on Fe metal + MORB glass at such high P-T conditions in a laser-heated diamond-anvil cell (DAC). The metal-silicate partitioning of carbon was examined by using two different sets of starting materials; carbon was included in Fe in one set of experiments, and it was contained as CO₂ in silicate glass in another set. After melting at high P, samples were recovered from a DAC, and their cross sections were prepared with a focused ion beam (FIB). Textural and compositional characterizations were made by electron microprobes. Subsequently carbon concentrations in coexisting molten iron and silicate melt were obtained by using a high-resolution imaging technique with secondary ion mass spectrometry (SIMS). These experimental results and the possible concentration of carbon in the core will be discussed at the meeting.