Effect of composition on compressibility of skiagite-Fe-majorite garnet
Effect of composition on compressibility of skiagite-Fe-majorite garnet
复制标题
成分对硅镁石-铁镁长石石榴石可压缩性的影响
DOI：
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
L. Dubrovinsky
中科院分区：
文献类型：
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作者：
L. Ismailova;M. Bykov;E. Bykova;A. Bobrov;I. Kupenko;V. Cerantola;D. Vasiukov;N. Dubrovinskaia;C. McCammon;M. Hanfland;K. Glazyrin;H. Liermann;A. Chumakov;L. Dubrovinsky
摘要：采用多砧装置，在7.5 ~ 9.5 GPa、1400 ~ 1600 K条件下合成了Skiagite-Fe-majorite石榴石。环境条件下的单晶x射线衍射表明，合成的石榴石含有23%至76%的铁-镁铁成分。我们发现，在环境条件下，八面体位置的Fe2+和Si4+取代Fe3+减少了石榴石的单位胞体积。对不同成分石榴石压缩至90 GPa时的单晶x射线衍射数据进行了分析，发现随着镁铁石成分的增加，石榴石的体积模量从159(1)增加到172(1)GPa。我们的研究结果和文献数据明确地表明，(Mg, Fe)-多数石中的总铁含量和Fe3+/Fe2+比对其弹性有很大的影响。在50 - 60 GPa的压力范围内，我们观察到镁铁镁石石榴石的摩尔体积与压力的单调关系出现了明显的偏差，在一个很小的压力区间内，其体积下降了约3%。通过结合单晶x射线衍射和高压同步加速器Mössbauer源光谱的结果，我们证明了这些压缩行为的变化与八面体位置铁电子态的变化有关。
Abstract Skiagite-Fe-majorite garnets were synthesized using a multianvil apparatus at 7.5–9.5 GPa and 1400–1600 K. Single-crystal X-ray diffraction at ambient conditions revealed that synthesized garnets contain 23 to 76% of an Fe-majorite component. We found that the substitution of Fe2+ and Si4+ for Fe3+ in the octahedral site decreases the unit-cell volume of garnet at ambient conditions. Analysis of single-crystal X-ray diffraction data collected on compression up to 90 GPa of garnets with different compositions reveals that with increasing majorite component the bulk modulus increases from 159(1) to 172(1) GPa. Our results and literature data unambiguously demonstrate that the total iron content and the Fe3+/Fe2+ ratio in (Mg, Fe)-majorites have a large influence on their elasticity. At pressures between 50 and 60 GPa we observed a significant deviation from a monotonic dependence of the molar volumes of skiagite-Fe-majorite garnet with pressure, and over a small pressure interval the volume dropped by about 3%. By combining results from single-crystal X-ray diffraction and high-pressure synchrotron Mössbauer source spectroscopy we demonstrate that these changes in the compressional behavior are associated with changes of the electronic state of Fe in the octahedral site.
影响因子：
3.7
作者：
Kantor, IY;Dubrovinsky, LS;McCammon, CA
通讯作者：
McCammon, CA
影响因子：
3.1
作者：
Cerantola, Valerio;McCammon, Catherine;Dubrovinsky, Leonid
通讯作者：
Dubrovinsky, Leonid