日時：2016年3月7日(月）16：30〜
場所：理学研究科1号館 4階　462号室
(世話人：川本　竜彦先生: 3938）

講演者：Kyusei Tsuno
　　　　Laboratory Manager
　　　　Department of Earth Science
　　　　Rice University, Houston, USA
　　　　
講演題目：Establishing the carbon and sulfur budget of the bulk silicate Earth during the multi‐
stage core formation processes

要旨：The origin, distribution and flux of Earth’s volatiles such as carbon and sulfur is of a
great importance to the long‐terms climate change, partial melting of the Earth’s mantle and
formation of the continental and oceanic crust. The solubility of C in S‐bearing alloy liquid is
crucial to understand the distribution of these volatiles in the mantle and core during the core
formation process. Experiments using a piston cylinder and multi‐anvil presses have been conducted
at 3‐6 GPa and 1600‐1800 °C to investigate the C solubility in S‐bearing Fe‐Ni GPa and 1600‐
1800 °C to investigate the C solubility in S‐bearing Fe‐Nialloy liquid. The results show that C‐
solubility in the Fe‐5 wt.% Ni alloy liquid varies from 5.0 wt% to 1.9 wt.% with increasing S
content from 3 to 35 wt.%. We use these new data combined with published C with published C
solubility and C and S partitioning in and between the alloy liquid and silicate melt [e.g., 1, 2]
to suggest a core formation scenario in which the C and S abundance and C/S ratio in the bulk
silicate Earth (BSE) could be established. Accretion of Mercury‐like (reduced) differentiated
planetary body to the growing Earth may explain the carbon budget of BSE owing to the low C
solubility in Si‐rich low C solubility in Si‐rich alloy liquid [1]. On the other hand, accretion
of S‐rich differentiated alloy liquid [1]. On the other hand, accretion of S‐rich differentiated
body to the growing Earth may not supply adequate amount of C in BSE owing to the relatively high C
not supply adequate amount of C in BSE owing to the relatively high C solubility (> 1.9 wt.%) in S-
bearing alloy liquid. It suggests that C‐bearing late veneer may be needed to alloy liquid. It make
up for the C insuggests that C‐bearing late veneer may be needed to make up for the C in the
silicate mantle after the core formation ceased. [1] Li et al. (2015) EPSL [2] Bojibar et al. (2014)
EPSL

説明
講演者の津野究成博士は、東北大学で博士号をとられてから、ドイツのバイエルン地球研究所で
ポスドク研究員を2年半された後、合衆国のテキサス州のライス大学で高温高圧実験室のラボマネージャーを7年
余りされています。 地球のマントルや中心核での軽元素の実験的研究をされています。今回は、著名な研究者
たちがこぞって研究しているテーマである中心核に炭素や硫黄がどのように入ったかについて最新の研究につい
て紹介してもらいます。