Challenging the highstand-dormant paradigm for land-detached submarine canyons

Maarten Heijnen (Lead Author), Furu Mienis, Andrew Gates, Brian Bett, Rob Hall, James Hunt, Ian Kane, Corrine Pebody, Veerle Huvenne, Euan Soutter, Michael Clare (Lead Author)

Research output: Contribution to journalArticlepeer-review

Abstract

Sediment, nutrients, organic carbon and pollutants are funnelled down submarine canyons from continental shelves by sediment-laden flows called turbidity currents, which dominate particulate transfer to the deep sea. Post-glacial sea-level rise disconnected more than three quarters of the > 9000 submarine canyons worldwide from their former river or long-shore drift sediment inputs. Existing models therefore assume that land-detached submarine canyons are dormant in the present-day; however, monitoring has focused on land-attached canyons and this paradigm remains untested. Here we present the most detailed field measurements yet of turbidity currents within a land-detached submarine canyon, documenting a remarkably similar frequency (6 yr− 1) and speed (up to 5–8 ms− 1) to those in large land-attached submarine canyons. Major triggers such as storms or earthquakes are not required; instead, seasonal variations in cross-shelf sediment transport explain temporal-clustering of flows, and why the storm season is surprisingly absent of turbidity currents. As > 1000 other canyons have a similar configuration, we propose that contemporary deep-sea particulate transport via such land detached canyons may have been dramatically under-estimated.
Original languageEnglish
Article number3448
JournalNature Communications
Volume13
DOIs
Publication statusPublished - 15 Jun 2022

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