Supplementary material

Fig. S1. Mössbauer spectra of (a) B2* zone 1 and (b) D1* and the associated tables with the Mössbauer hyperfine parameters and the different contents of each sub-spectra. The values in brackets denote the error corresponding to the associated value. hem: hematite, mgt: magnetite, spt: serpentine. obs.: observed, calc.: calculated.

Table S1. Serpentine electron microprobe analyses (wt% and number of cations). The detection limits were 640 ppm, 510 ppm, 420 ppm, 640 ppm, 730 ppm, 970 ppm, 1010 ppm, 6760 ppm, 440 ppm, 280 ppm, 930 ppm, 920 ppm, 330 ppm, and 1100 ppm for Na, Si, Al, K, Ca, Mn, Fe, F, Mg, Cl, Ba, Ti, Cr, and Ni, respectively.

Table S2. Calcite electron microprobe analyses (wt% and number of cations). The complement of the total (wt%) is equivalent to CO₂ (wt%). The detection limits were 760 ppm, 400 ppm, 370 ppm, 560 ppm, 1060 ppm, 1010 ppm, 1050 ppm, 10,210 ppm, 450 ppm, 250 ppm, 1010 ppm, 1020 ppm, 350 ppm, and 1130 ppm for Na, Si, Al, K, Ca, Mn, Fe, F, Mg, Cl, Ba, Ti, Cr, and Ni, respectively.

© D. Lévy et al., Published by EDP Sciences 2022