High-pressure synthesis and storage of solid organic compounds in active subduction zones

• DOI: 10.1126/sciadv.abo2397
• Publication Date: 2022-09-16T17:58:17Z
• Authors: Baptiste Debret; Bénédicte Ménez; Bastien Walter; Hélène Bouquerel; Pierre Bouilhol; Nadine Mattielli; Céline Pisapia; Thomas Rigaudier; Helen Myfanwy Wil...
• Keywords: Forearc; Peridotite; Slab

Recent thermodynamic and experimental studies have suggested that volatile organic compounds (e.g., methane, formate, acetate) can be produced stabilized in subduction zones, potentially playing an important role the deep carbon cycle. However, field evidence for high-pressure production storage of solid is missing. Here, we examine forearc serpentinite clasts recovered by drilling mud volcanoes above Mariana zone. Notable correlations between iron stable-isotope signatures fluid-mobile element (B, As Sb) concentrations provide percolation slab-derived CO2-rich aqueous fluids through mantle. The presence carbonaceous matter rich aliphatic moieties within high-temperature (>350°C) demonstrates molecular hydrogen associated with serpentinization efficient mechanism reduction conversion into compounds. These findings emphasize need to consider mantle as reservoir on Earth.