The fate of nitrogen during core-mantle separation on Earth

Core formation and magma ocean outgassing set planetary N-S-C ratios

“…We completed independent series of experiments to quantify the P-T-X controls on N partitioning between liquid metal and silicate ( , atomic fraction, Figure 3, (Figure 3b, Supplementary Figures 1 and 2). Our ƒO 2 and temperature findings accord with previous work [24][25][26] . We also find that has a negative effect on values, but this effect is not significant at the % confidence level in our dataset (p-value = 0.12, Supplementary Figure 2).…”

“…Silicon nitride was used as the standard (MTI Corporation) for N analysis, following the approach of 23. No evidence for N mobility under the electron beam was observed, in agreement with other studies of N partitioning that employed similar analytical techniques 23,25 .…”

“…to literature data to validate its predictive power (Supplementary Figure 3). We predict literature data 20,22,25,26 Figure 4).…”

“…This result implies that core formation under the P-T conditions associated with larger terrestrial planets, such as Earth, is an efficient mechanism to increase S/N and C/N ratios in observable reservoirs by preferentially sequestering N to the core. Previous work has also identified that values increase with pressure (P/T) 20,24,25 , but experiments were limited to more moderate conditions and application to core formation in Earth required correspondingly large pressure extrapolation.…”

“…Core formation fractionates elements on the basis of their preference for the metallic phase. For the relatively low pressure and temperature (P-T) conditions associated with core formation in planetesimals, sulfur and carbon both display a greater preference for the metal phase (more siderophile behavior) than nitrogen e.g., [18][19][20][21][22][23][24][25][26] , provided planetesimal S and C concentrations remain at levels associated with planets 27 . Strongly siderophile S and C would lead to low S/N and C/N observable ratios for planetesimals, the opposite of what is observed for Earth 2,5,6 .…”