Phase relations of Fe-Si alloy up to core conditions: Implications for the Earth inner core
Phase relations of Fe-Si alloy up to core conditions: Implications for the Earth inner core
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DOI：
10.1029/2008gl033863
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发表时间：
2008-06-25
影响因子：
5.2
通讯作者：
Ohishi, Yasuo
中科院分区：
文献类型：
--
作者：
Asanuma, Hidetoshi;Ohtani, Eiji;Ohishi, Yasuo
在257 GPa和高温下对含硅3.4 wt%的铁硅合金进行了x射线衍射实验，这是地球内核形成材料的候选材料。结果表明，fcc相和hcp相在104 GPa时共存。单个hcp相在较高的压力下是稳定的，至少在242gpa下达到3600k，在257gpa下达到2400k。在地核形成过程中，硅在液态外核与硅酸盐地幔反应后的溶解，强烈表明硅在固态内核中存在。我们的研究结果表明，内核中的铁-3.4 wt%硅合金可能具有hcp结构，这可以解释地震学观测到的内核各向异性。
X-ray diffraction experiments were conducted to 257 GPa and high temperature in situ on an iron-silicon alloy containing 3.4 wt% silicon, a candidate for the Earth's inner core forming material. The results revealed that fcc and hcp phases coexist up to 104 GPa. A single hcp phase is stable at higher pressures at least up to 3600 K at 242 GPa and to 2400 K at 257 GPa. Dissolution of silicon in the liquid outer core following reaction with the silicate mantle during core formation strongly suggests the existence of silicon in the solid inner core. Our results revealed that the iron-3.4 wt% silicon alloy in the inner core is likely to possess an hcp structure, which can explain the inner core anisotropy observed in seismology.