High Pressure Melting of Pyrolite Under Hydrous Condition and its Geophysical Implications
High Pressure Melting of Pyrolite Under Hydrous Condition and its Geophysical Implications
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DOI：
10.1029/gm067p0323
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发表时间：
2013-03
影响因子：
3.1
通讯作者：
T. Inoue;H. Sawamoto
中科院分区：
文献类型：
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作者：
T. Inoue;H. Sawamoto
在含水条件下，在高达7.7 GPa的五组分系统（CaO-MgO-FeO-Al 2 O3-SiO2）中，在各种含水量（2.9wt%，8.3wt%和15.6wt%）下，对模型地幔成分（软锰矿）进行熔融实验。固相线和液相线温度都随着水含量的增加而降低：对于7.7 GPa下含有15.6 wt%水的系统，它们分别比干燥橄榄岩的温度低700°C和550°C。随着压力和含水量的增加，第一液相由橄榄石转变为斜方辉石或镁铝榴石，而在无水条件下，当压力达到15 GPa时，橄榄石是唯一的第一液相。在7.7GPa的含水体系中，部分熔体具有高的Mg/Si比，为1.8，它变成超基性的。
Melting experiments were conducted on model mantle composition (pyrolite) in the five‐component system (CaO‐MgO‐FeO‐Al2O3‐SiO2) up to 7.7 GPa under hydrous conditions at various water contents (2.9 wt%, 8.3 wt% and 15.6 wt%). Both the solidus and the liquidus temperatures decrease with increasing water content: They are lower than those of the dry peridotite by 700°C and 550°C, respectively, for the system containing 15.6 wt% water at 7.7 GPa. the first liquidus phase changes from olivine to orthopyroxene or pyrope garnet with increasing pressure and water content, while olivine is the only first liquidus phase up to 15 GPa in anhydrous condition. the partial melt in the hydrous system at 7.7 GPa has a high Mg/Si ratio of ∼1.8; it becomes ultrabasic.