One of the most remarkable observations regarding volatile elements in the solar system is the depletion of N in the bulk silicate Earth (BSE) relative to chondrites, leading to a particularly high and non-chondritic C:N ratio. The N depletion may reflect large-scale differentiation events such as sequestration in Earth's core or massive blow off of Earth's early atmosphere, or alternatively the characteristics of a late-added volatile-rich veneer. As the behavior of N during early planetary differentiation processes is poorly constrained, we determined together the partitioning of N and C between Fe-N-C metal alloy and two different silicate melts (a terrestrial and a martian basalt). Conditions spanned a range of f O2 from IW-0.4 to IW-3.5 at 1.2 to 3 GPa, and 1400ºC or 1600ºC, where IW is the logarithmic difference between experimental f O2 and that imposed by the coexistence of crystalline Fe and wüstite.

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