Partition coefficient of phosphorus between liquid metal and silicate melt with implications for the Martian magma ocean

In this study, we investigated the behavior of phosphorus in a Martian magma ocean scenario, and measured the partition coefficient of phosphorus (DP) between liquid metal and silicate melt within the pressure range of 3–8 GPa, temperatures between 1973 and 2173 K and oxygen fugacity ranging from −1.5 to ~ −2.5 as normalized to the iron-wüstite oxygen buffer. Our results show DP increasing with pressure but decreasing with temperature. A decrease of oxygen fugacity has a negative effect on DP. The moderately siderophile character of phosphorus indicates that the Martian core might be an important reservoir of phosphorous. Based on our experimental results and phosphorus abundance in Martian mantle and bulk Mars, a minimum pressure of 5.8–10.4 GPa is estimated at the base of Martian magma ocean or during the impact melting if a contribution from the late accretion scenario is taken into account. The shallow Martian magma ocean would avail the preservation of volatiles after the rapid solidification of the planet.

Source: Physics of the Earth and Planetary Interiors - August 16, 2019 Category: Physics Source Type: research