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Fig. 9 | Progress in Earth and Planetary Science

Fig. 9

From: Redox-controlled mechanisms of C and H isotope fractionation between silicate melt and COH fluid in the Earth’s interior

Fig. 9

Carbon isotope ratio evolution in coexisting melt and fluid as a function of temperature and pressure in silicate–COH systems. a. Under oxidizing conditions with carbon residing in CO32− and HCO3 groups. The bulk carbon isotope ratio was calculated with Eq. (11). Insert shows Raman spectrum of 0.7 m NaHCO3 solution with approximately 50:50 13C:12C at ambient temperature and pressure. b Under reducing conditions with carbon residing in CH4 and CH3 groups. The individual effect of these to complexes could not be resolved with Raman spectroscopy so the isotope ratio is reported in bulk. Insert shows Raman spectrum of fumaric acid with approximately 50:50 13C:12C. (data from Mysen 2016, 2017)

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