Partitioning of molybdenum to 60 kbar along a warped Fe–FeS liquidus

Mo partitioning between crystalline and liquid metal alloy shows a continuous change with pressure from siderophile to chalcophile behavior at 1100 °C in the interval 0–60 kbar. Pressure is shown to be only a minor direct causative factor in this change. Unusual Fe–S liquid solution behavior causes Fe to dissolve instead of precipitate from solution with increasing pressure to 60 kbar at temperatures up to ∼ 1375 °C. This pathology drives changes in DMo that overshadow any direct pressure effect on DMo. The ability to separate the pressure and compositional effects on DMo arises through the warpage in pressure of the Fe–S liquidus.