Geochemistry of sediment cores GeoB13820-1 and GeoB13863-1 from the western South Atlantic

DOI

Here, we present results from sediments collected in the Argentine Basin, a non-steady state depositional marine system characterized by abundant oxidized iron within methane-rich layers due to sediment reworking followed by rapid deposition. Our comprehensive inorganic data set shows that iron reduction in these sulfate and sulfide-depleted sediments is best explained by a microbially mediated process-implicating anaerobic oxidation of methane coupled to iron reduction (Fe-AOM) as the most likely major mechanism. Although important in many modern marine environments, iron-driven AOM may not consume similar amounts of methane compared with sulfate-dependent AOM. Nevertheless, it may have broad impact on the deep biosphere and dominate both iron and methane cycling in sulfate-lean marine settings. Fe-AOM might have been particularly relevant in the Archean ocean, >2.5 billion years ago, known for its production and accumulation of iron oxides (in iron formations) in a biosphere likely replete with methane but low in sulfate. Methane at that time was a critical greenhouse gas capable of sustaining a habitable climate under relatively low solar luminosity, and relationships to iron cycling may have impacted if not dominated methane loss from the biosphere.

Supplement to: Riedinger, Natascha; Formolo, Michael J; Lyons, Timothy W; Henkel, Susann; Beck, Antje; Kasten, Sabine (2014): An inorganic geochemical argument for coupled anaerobic oxidation of methane and iron reduction in marine sediments. Geobiology, 12(2), 172-181

Identifier
DOI https://doi.org/10.1594/PANGAEA.773188
Related Identifier IsSupplementTo https://doi.org/10.1111/gbi.12077
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.773188
Provenance
Creator Riedinger, Natascha ORCID logo; Formolo, Michael J; Lyons, Timothy W; Henkel, Susann ORCID logo; Beck, Antje; Kasten, Sabine ORCID logo
Publisher PANGAEA
Publication Year 2014
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 8 datasets
Discipline Earth System Research
Spatial Coverage (-53.967W, -39.312S, -53.953E, -39.301N)
Temporal Coverage Begin 2009-06-01T03:12:00Z
Temporal Coverage End 2009-06-29T14:38:00Z