Phase Relations in MAFSH System up to 21 GPa: Implications for Water Cycles in Martian Interior
Phase Relations in MAFSH System up to 21 GPa: Implications for Water Cycles in Martian Interior
复制标题
DOI：
10.3390/min9090559
复制
发表时间：
2019-09
期刊：
影响因子：
2.5
通讯作者：
Chaowen Xu;T. Inoue
中科院分区：
文献类型：
--
作者：
Chaowen Xu;T. Inoue
为了阐明富铁火星中的水循环，我们研究了水不饱和（2 wt.%）在900-1500 °C下使用多砧装置在15和21 GPa之间在简化的MgO-Al 2 O3-FeO-SiO2-H2O（MAFSH）系统中模拟火星地幔。结果表明，在15 ~ 16.5GPa和1050 °C以下，E相至少是稳定的。D相在压力高于16.5 GPa和温度低于1100 °C时与林伍德石共存。在富铁系统中，与地球的含水软锰矿模型相比，在富铁软锰矿-灵伍德岩边界处的环的过渡压力向低压方向移动。一些证据表明，在古代火星的火星表面曾经存在水。存在于含水地壳中的水可能是由对流地幔带入深部的。因此，水可能是通过含水矿物，如冷俯冲板块中的E相和D相，被输送到火星内部深处的。此外，当板块与周围的火星地幔热平衡时，这些含水物质分解后，它可能被储存在wadsleyite或ringwoodite中。
To elucidate the water cycles in iron-rich Mars, we investigated the phase relation of a water-undersaturated (2 wt.%) analog of Martian mantle in simplified MgO-Al2O3-FeO-SiO2-H2O (MAFSH) system between 15 and 21 GPa at 900–1500 °C using a multi-anvil apparatus. Results showed that phase E coexisting with wadsleyite or ringwoodite was at least stable at 15–16.5 GPa and below 1050 °C. Phase D coexisted with ringwoodite at pressures higher than 16.5 GPa and temperatures below 1100 °C. The transition pressure of the loop at the wadsleyite-ringwoodite boundary shifted towards lower pressure in an iron-rich system compared with a hydrous pyrolite model of the Earth. Some evidence indicates that water once existed on the Martian surface on ancient Mars. The water present in the hydrous crust might have been brought into the deep interior by the convecting mantle. Therefore, water might have been transported to the deep Martian interior by hydrous minerals, such as phase E and phase D, in cold subduction plates. Moreover, it might have been stored in wadsleyite or ringwoodite after those hydrous materials decomposed when the plates equilibrated thermally with the surrounding Martian mantle.