Experimental study of trace element partitioning between lunar orthopyroxene and anhydrous silicate melt: effects of lithium and iron

Orthopyroxene (Opx) was present during a significant portion of crystallisation of the lunar magma ocean, but its influence on co-existing melt trace element contents is not well quantified. We performed high-pressure (P, 1.1 to 3.2GPa), high-temperature (T, 1400 to 1600°C) experiments on synthetic Fe-rich compositions at reducing conditions relevant to the lunar mantle to constrain trace element partitioning between Opx and anhydrous silicate melts. Opx-melt partition coefficients (