Crystallization experiments on a Gusev Adirondack basalt composition
Crystallization experiments on a Gusev Adirondack basalt composition
复制标题
古谢夫阿迪朗达克玄武岩组合物的结晶实验
DOI：
10.1111/j.1945-5100.2008.tb01118.x
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发表时间：
2008
影响因子：
2.2
通讯作者：
L. Le
中科院分区：
文献类型：
--
作者：
J. Filiberto;A. Treiman;L. Le
直到最近，SNC陨石代表了关于火星表面和地幔的化学和岩石学信息的唯一来源。火星探测漫游者现在已经分析了火星表面的岩石，对火星的岩石学和地球化学有了更多的了解。在古谢夫陨石坑中由MER Spirit分析的阿迪朗达克玄武岩是橄榄石-斑状玄武岩，被认为代表液体，因此可能为火星地幔的化学提供新的见解。在上地幔和地壳条件下对合成Humphrey成分进行了实验，以研究该成分是否可能代表原始地幔熔体。Humphrey的成分在12.5 kbar和1375 °C下被橄榄石和钙铝榴石多重饱和;来自“南极”地幔的原生无水熔体预计将被斜方辉石饱和，而不是钙铝榴石。此外，在多重饱和度下的橄榄石和褐变岩的铁性太强，不可能像现在所理解的那样来自火星地幔。因此，汉弗莱的成分似乎并不代表火星地幔的原生无水熔体，而是在较低的（地壳）压力下受到矿物/熔体分馏的影响。
Abstract— Until recently, the SNC meteorites represented the only source of information about the chemistry and petrology of the Martian surface and mantle. The Mars Exploration Rovers have now analyzed rocks on the Martian surface, giving additional insight into the petrology and geochemistry of the planet. The Adirondack basalts, analyzed by the MER Spirit in Gusev crater, are olivine‐phyric basaltic rocks which have been suggested to represent liquids, and might therefore provide new insights into the chemistry of the Martian mantle. Experiments have been conducted on a synthetic Humphrey composition at upper mantle and crustal conditions to investigate whether this composition might represent a primary mantle‐derived melt. The Humphrey composition is multiply saturated at 12.5 kbar and 1375 °C with olivine and pigeonite; a primary anhydrous melt derived from a “chondritic” mantle would be expected to be saturated in orthopyroxene, not pigeonite. In addition, the olivine and pigeonite present at the multiple saturation are too ferroan to have been from a Martian mantle as is understood now. Therefore, it seems likely that the Humphrey composition does not represent a primary anhydrous melt from the Martian mantle, but was affected by mineral/melt fractionations at lower (crustal) pressures.