Challenging the highstand-dormant paradigm for land-detached submarine canyons
Heijnen, M.S.; Mienis, F.; Gates, A.R.; Bett, B.J.; Hall, R.A.; Hunt, J.; Kane, I.A.; Pebody, C.; Huvenne, V.A.I.; Soutter, E.L.; Clare, M.A. (2022). Challenging the highstand-dormant paradigm for land-detached submarine canyons. Nature Comm. 13(1): 3448. https://dx.doi.org/10.1038/s41467-022-31114-9Additional data: In: Nature Communications. Nature Publishing Group: London. ISSN 2041-1723; e-ISSN 2041-1723, more |   |
| Authors | | Top | - Heijnen, M.S.
- Mienis, F., more
- Gates, A.R.
- Bett, B.J.
| - Hall, R.A.
- Hunt, J.
- Kane, I.A.
- Pebody, C.
| - Huvenne, V.A.I., more
- Soutter, E.L.
- Clare, M.A.
|
| 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. |
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