Gravity complexes as a focus of seafloor fluid seepage : the Rio Grande Cone, SE Brazil

© 2023. The Author(s)..

Seafloor methane emissions can affect Earth's climate and ocean chemistry. Vast quantities of methane formed by microbial decomposition of organic matter are locked within gas hydrate and free gas on continental slopes, particularly in large areas with high sediment accumulations such as deep-sea fans. The release of methane in slope environments has frequently been associated with dissociation of gas hydrates near the edge of the gas hydrate stability zone on the upper slope, with discharges in greater water depths less understood. Here we show, using data from the Rio Grande Cone (western South Atlantic), that the intrinsic, gravity-induced downslope collapse of thick slope sediment accumulations creates structures that serve as pathways for gas migration, unlocking methane and causing seafloor emissions via giant gas flares in the water column. The observed emissions in the study region (up to 310 Mg year-1) are three times greater than estimates for the entire US North Atlantic margin and reveal the importance of collapsing sediment accumulations for ocean carbon cycling. Similar outgassing systems on the Amazon and Niger fans suggest that gravity tectonics on passive margins is a common yet overlooked mechanism driving massive seafloor methane emissions in sediment-laden continental slopes.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:13

Enthalten in:

Scientific reports - 13(2023), 1 vom: 21. März, Seite 4590

Sprache:

Englisch

Beteiligte Personen:

Ketzer, M [VerfasserIn]
Praeg, D [VerfasserIn]
Augustin, A H [VerfasserIn]
Rodrigues, L F [VerfasserIn]
Steiger, A K [VerfasserIn]
Rahmati-Abkenar, M [VerfasserIn]
Viana, A R [VerfasserIn]
Miller, D J [VerfasserIn]
Malinverno, A [VerfasserIn]
Dickens, G R [VerfasserIn]
Cupertino, J A [VerfasserIn]

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Journal Article

Anmerkungen:

Date Completed 22.03.2023

Date Revised 24.03.2023

published: Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1038/s41598-023-31815-1

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM354499092