Carbon and sediment fluxes inhibited in the submarine Congo Canyon by landslide-damming

Type Article
Date 2022-10
Language English
Author(s) Pope Ed L.ORCID1, Heijnen Maarten S.2, 3, Talling Peter J.ORCID1, Silva Jacinto Ricardo4, Gaillot Arnaud4, Baker Megan L.ORCID1, Hage SophieORCID5, 6, Hasenhündl MartinORCID7, Heerema Catharina J.1, 8, McGhee Claire9, Ruffell Sean C.ORCID1, Simmons Stephen M.ORCID10, Cartigny Matthieu J. B.ORCID1, Clare Michael A.ORCID2, Dennielou BernardORCID4, Parsons Daniel R.ORCID10, Peirce ChristineORCID1, Urlaub MoreliaORCID11
Affiliation(s) 1 : Departments of Geography and Earth Science, Durham University, Durham, UK
2 : National Oceanography Centre Southampton, Southampton, UK
3 : School of Ocean and Earth Sciences, University of Southampton, Southampton, UK
4 : Marine Geosciences Unit, IFREMER Centre de Brest, Plouzané, France
5 : Department of Geosciences, University of Calgary, Calgary, Alberta, Canada
6 : Univ Brest, CNRS, Ifremer, Geo-Ocean, Plouzané, France
7 : Institute of Hydraulic Engineering and Water Resources Management, TU Wien, Vienna, Austria
8 : Department of Geography, University of Victoria, Victoria, British Columbia, Canada
9 : School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne, UK
10 : Energy and Environment Institute, University of Hull, Hull, UK
11 : GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
Source Nature Geoscience (1752-0894) (Springer Science and Business Media LLC), 2022-10 , Vol. 15 , N. 10 , P. 845-853
DOI 10.1038/s41561-022-01017-x

Landslide-dams, which are often transient, can strongly affect the geomorphology, and sediment and geochemical fluxes, within subaerial fluvial systems. The potential occurrence and impact of analogous landslide-dams in submarine canyons has, however, been difficult to determine due to a scarcity of sufficiently time-resolved observations. Here we present repeat bathymetric surveys of a major submarine canyon, the Congo Canyon, offshore West Africa, from 2005 and 2019. We show how an ~0.09 km3 canyon-flank landslide dammed the canyon, causing temporary storage of a further ~0.4 km3 of sediment, containing ~5 Mt of primarily terrestrial organic carbon. The trapped sediment was up to 150 m thick and extended >26 km up-canyon of the landslide-dam. This sediment has been transported by turbidity currents whose sediment load is trapped by the landslide-dam. Our results suggest canyon-flank collapses can be important controls on canyon morphology as they can generate or contribute to the formation of meander cut-offs, knickpoints and terraces. Flank collapses have the potential to modulate sediment and geochemical fluxes to the deep sea and may impact efficiency of major submarine canyons as transport conduits and locations of organic carbon sequestration. This has potential consequences for deep-sea ecosystems that rely on organic carbon transported through submarine canyons.

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Pope Ed L., Heijnen Maarten S., Talling Peter J., Silva Jacinto Ricardo, Gaillot Arnaud, Baker Megan L., Hage Sophie, Hasenhündl Martin, Heerema Catharina J., McGhee Claire, Ruffell Sean C., Simmons Stephen M., Cartigny Matthieu J. B., Clare Michael A., Dennielou Bernard, Parsons Daniel R., Peirce Christine, Urlaub Morelia (2022). Carbon and sediment fluxes inhibited in the submarine Congo Canyon by landslide-damming. Nature Geoscience, 15(10), 845-853. Publisher's official version : , Open Access version :