[SGC48-11] The effects of carbon concentration and silicate melt structure on the metal-silicate partitioning of carbon in a shallow magma ocean
Keywords:Carbon, Core-mantle partitioning, Magma ocean
In this study, we conducted high-pressure experiments on liquid metal-silicate partitioning of carbon using a SiO2 capsule and multi-anvil apparatus at 2 GPa and 1923 K. The starting materials were prepared from mixtures of metallic Fe and Ni, and oxide. For silicate compositions, we used two types of compositions: EH-type enstatite chondrite and mid-ocean ridge basalt. 0.2 wt% of carbon was added to these starting materials as Na2CO3. Carbon in quenched metallic liquid and silicate liquid were analyzed by electron probe micro-analyzer and secondary ion mass spectrometry, respectively. Chemical species of volatiles and the melt structure of quenched silicate glasses were analyzed by Raman spectroscopy. The experimental results show that the metal-silicate partition coefficient of carbon at carbon-undersaturated conditions is lower than that reported using a graphite capsule. Raman spectroscopic analyses show the presence of CH species and amorphous carbon in silicate and that the carbon abundance in silicate liquids increases with increasing non-bridging oxygen. These results suggest that the metal-silicate partitioning behavior of carbon depedns both on carbon concentration and silicate melt structure. In this talk, we will also discuss the application of experimental results to the Earth.
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