Fig. 3: Diversity of gaseous and condensed abiotic organic compounds associated with secondary minerals in single fluid inclusions trapped in olivine minerals of the deep oceanic lithosphere.

a Three dimensional Raman imaging of fluid inclusion FI3 showing polyaromatic carbonaceous materials (PACMs)^33,34,35,36 coexisting with reduced gaseous species identified as H₂, N₂, CH₄, and CH₃SH and micrometric serpentinization-derived mineral phases^109,111 (i.e., serpentine, brucite, magnetite, and carbonate). See also Supplementary Movie 1. b Raman spectra highlighting the 3 end-member types of PACMs in the two individual fluid inclusions (FI3 and FI5), all characterized by two broad bands assigned to the disorder (D) band and the graphite (G) band but showing variable position, intensity and width. For each end-member, a mean Raman spectrum is presented (bold line) with the standard deviation (colored shadows). c False color scanning electron microscopy (SEM) image of FI5 fluid inclusion freshly opened by focused ion beam milling showing distinct types of PACMs which contrast by their apparent textures: gel-like or mesoporous with nanofilaments are characteristic of PACM1 and PACM2, respectively. d Associated elemental mapping using energy dispersive X-ray spectrometry of the olivine (Ol) hosted fluid inclusion allows the identification of PACMs, fibrous polygonal serpentine (F. Srp), lamellar serpentine (lizardite, Lz), polyhedral serpentine (P. Srp), calcite (Cal), and brucite (Brc), as also supported by Raman microspectroscopy (Fig. 2). e, f Magnified SEM views of c, highlighting PACM1 and PACM2, respectively.