1. Mars High-Pressure Experiments COSMOCHEMISTRY iLLUSTRATED A Martian Primary Magma Olivine compositions in Martian meteorite Y-980459 indicate crystallization from a magma with a composition the same as bulk Y-980459.

2. Mars High-Pressure Experiments COSMOCHEMISTRY iLLUSTRATED High-Pressure Experiments Experimental apparatus and SEM image of an experimental run product.

3. Mars High-Pressure Experiments COSMOCHEMISTRY iLLUSTRATED Experimental Results Series of experiments allows construction of a phase diagram The magma has both olivine and pyroxene on its liquidus at about 12 kbar (depth of 100 km in Mars) Unless the amount of partial melting was extremely large, this is likely the pressure at which the magma formed

4. Mars High-Pressure Experiments COSMOCHEMISTRY iLLUSTRATED The Martian Mantle At multiple saturation, residual minerals have Mg# of 0.86 This implies that the mantle source region for Y-098459 had this value if the amount of melting was very low Consensus value for Martian mantle is Mg# of 0.75, implying very high % melting Options: - Martian mantle Mg# is > 0.75, - Martian mantle is heterogeneous - Y-098459 source was melted more than once