Fig. 2: Compositional differences between OM patches preserved via the two modes.

a, b, Surface coating OM (mode I) and pore occluded OM (mode II) are circled by red and green lines respectively. c-f, Spatial distribution of C/N and δ13C composition of the surface coating OM (mode I, c, e) and pore occluded OM (mode II, d, f). g, h, Box plots of C/N (g) and δ13C (h) differences between the OM preserved via two modes: boxes represent the range 25–75% with medians as the middle lines, and whiskers represent standard deviation.