Liquidus Phase Relations and Solid-Liquid Partitioning in the Fe-Si-C System Under Core Pressures
Liquidus Phase Relations and Solid-Liquid Partitioning in the Fe-Si-C System Under Core Pressures
复制标题
核心压力下 Fe-Si-C 体系中的液相线相关系和固液分配
DOI：
10.1002/essoar.10507125.1
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发表时间：
2021
影响因子：
3.7
通讯作者：
Y. Ohishi
中科院分区：
文献类型：
--
作者：
K. Hirose;M. Hasegawa;K. Oka;Y. Ohishi
硅和碳都被认为是地核中重要的轻元素，特别是在内核中。在~50、~136和~200 GPa下对Fe-Si-C三元系进行了熔化实验，测定了C和Si的液相线相关系和固/液分配系数（D）。Fe的液相线场在较高的压力下收缩，这缩小了可能的外核液体成分。我们的数据还表明，Fe-Si二元共晶液体随着压力增加到330 GPa而将其Si浓度降低到约8重量%。我们发现，内核不是Fe-Si-C-S合金，但可能包括氢时，考虑到低DC和强烈增强的DSi与液体C丰度增加。现今的核心不包括多达~ 6wt%的Si，这表明至少一部分“缺失的”Si可以被封存在其他地方。
Both silicon and carbon have been proposed to be important light elements in the Earth’s core, in particular in the inner core. Here we performed melting experiments on the Fe-Si-C ternary system at ~50, ~136, and ~200 GPa and determined the liquidus phase relations and the solid/liquid partition coefficients (D) of C and Si. The liquidus field of Fe shrinks at higher pressures, which narrows down the possible outer core liquid composition. Our data also demonstrate that the Fe-Si binary eutectic liquid reduces its Si concentration to ~8 wt% with increasing pressure to 330 GPa. We found that the inner core is not Fe-Si-C-S alloy but likely includes hydrogen when considering the low DC and the strong enhancement of DSi with increasing liquid C abundance. The present-day core does not include as much as ~6 wt% Si, suggesting that at least a part of “missing” Si could be sequestrated elsewhere.