[S-IT31] 惑星中心核：構造，形成と進化

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

*堤 裕太郎¹、坂本 直哉²、廣瀬 敬³、横尾 舜平¹、田川 翔⁴、圦本 尚義⁵ (1.東京大学、2.北海道大学創成研究機構、3.東京工業大学大学　地球生命研究所、4.東京大学大学院理学系研究科地球惑星科学専攻、5.北海道大学理学研究院自然史科学部門)

キーワード：外核、軽元素、融解実験、炭素、水素

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.