Hage, Sophie and Cartigny, Matthieu J.B. and Sumner, Esther J. and Clare, Michael A. and Hughes Clarke, John E. and Talling, Peter J. and Lintern, D. Gwyn and Simmons, Stephen M. and Silva Jacinto, Ricardo and Vellinga, Age J. and Allin, Joshua R. and Azpiroz‐Zabala, Maria and Gales, Jenny A. and Hizzett, Jamie L. and Hunt, James E. and Mozzato, Alessandro and Parsons, Daniel R. and Pope, Ed L. and Stacey, Cooper D. and Symons, William O. and Vardy, Mark E. and Watts, Camilla (2019) 'Direct monitoring reveals initiation of turbidity currents from extremely dilute river plumes.', Geophysical research letters., 46 (20). pp. 11310-11320.
Abstract
Rivers (on land) and turbidity currents (in the ocean) are the most important sediment transport processes on Earth. Yet, how rivers generate turbidity currents as they enter the coastal ocean remains poorly understood. The current paradigm, based on laboratory experiments, is that turbidity currents are triggered when river plumes exceed a threshold sediment concentration of ~1 kg.m‐3. Here we present direct observations of an exceptionally dilute river‐plume, with sediment concentrations one order of magnitude below this threshold (0.07 kg.m‐3), which generated a fast (1.5 m.s‐1), erosive, short‐lived (6 min) turbidity current. However, no turbidity current occurred during subsequent river‐plumes. We infer that turbidity currents are generated when fine‐sediment, accumulating in a tidal turbidity maximum, is released during spring tide. This means that very dilute river‐plumes can generate turbidity currents more frequently and in a wider range of locations, than previously thought.
Item Type: | Article |
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Full text: | Publisher-imposed embargo (AM) Accepted Manuscript File format - PDF (797Kb) |
Full text: | (VoR) Version of Record Available under License - Creative Commons Attribution. Download PDF (Advance online version) (15224Kb) |
Full text: | (VoR) Version of Record Available under License - Creative Commons Attribution. Download PDF (15673Kb) |
Status: | Peer-reviewed |
Publisher Web site: | https://doi.org/10.1029/2019GL084526 |
Publisher statement: | © 2019. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
Date accepted: | 02 September 2019 |
Date deposited: | 10 October 2019 |
Date of first online publication: | 13 September 2019 |
Date first made open access: | 20 November 2019 |
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