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ing experiments of a model Martian mantle derived by Dreibus and Wänke (DWM) at pressures from 1.0 to 4.5. GPa. ..... Table 2 lists the run conditions, phase relations and degree of melting of run ...... Gusev plains, Gusev crater, Mars.

-4.5 GPa Journal of Mineralogical Melting and Petrological Sciences, J − STAGE Publication, June 18, 2013 of the Martian mantle from 1.0Advance

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Kyoko N. Matsukage*, ‡, Yoko Nagayo*, †, Matthew L. Whitaker*, §, Eiichi Takahashi** and Toshisuke Kawasaki***

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Melting of the Martian mantle from 1.0 to 4.5 GPa

* Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan *** Earth Sciences, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan ‡ Present address: Graduate School of Human and Environmental Sciences, Kyoto University, Yoshida-Nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan † Present address: Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan § Present address: Mineral Physics Institute, Stony Brook University,Stony Brook, NY 11794-2100, USA

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To investigate the chemical composition of possible primitive melts of the Martian mantle, we performed melting experiments of a model Martian mantle derived by Dreibus and Wänke (DWM) at pressures from 1.0 to 4.5 GPa. The chemical compositions of partial melts are systematically related to pressure. The partial melts at pressure of 1.0 GPa in spinel stability field show high Al2O3 and low FeO contents. The partial melts at higher pressure in garnet stability field are, however, characterized by a relatively high FeO content, low Al2O3 content and high CaO/Al2O3 ratio. In garnet stability field, clinopyroxene (= Ca-rich phase) contribute significantly to melt formation near the solidus temperature, although garnet (= Al-rich phase) is stable at temperature above solidus. Therefore Al-poor and Ca-rich partial melt are formed at higher pressure. Comparing the shergottite chemistry with the chemical trends of the partial melts obtained by the experiments, we suggest that one of basaltic shergottite with a high Al2O3 and low CaO/Al2O3 ratio, QUE94201, resembles the composition of the DWM partial melts in major-element chemistry in a low degree (