Fig. 3.
Core carbon content as a function of the pressure of core formation (with temperature along the peridotite liquidus of 27) and oxygen content of the core. Calculation is for single-stage core formation, assuming a mantle carbon content of 120 ppm (29), a peridotitic NBO/T of 2.6, oxygen fugacity of IW–2.2, and a core sulfur content of XS = 0.03 (e.g., ref. 7). Dotted lines: approximate core oxygen contents from previous studies (28, 30, 34). (A) Based on fit using nanoSIMS analyses for silicate C from the present study (Eq. 1). (B) Based on fit using microprobe analyses for silicate C from the present study (Eq. 2).