TY - JOUR
T1 - Direct Monitoring Reveals Initiation of Turbidity Currents From Extremely Dilute River Plumes
AU - Hage, Sophie
AU - Cartigny, Matthieu J.B.
AU - Sumner, Esther J.
AU - Clare, Michael A.
AU - Hughes Clarke, John E.
AU - Talling, Peter J.
AU - Lintern, D. Gwyn
AU - Simmons, Stephen M.
AU - Azpiroz-Zabala, Maria
AU - More Authors, null
PY - 2019
Y1 - 2019
N2 - 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/m3. Here we present direct observations of an exceptionally dilute river plume, with sediment concentrations 1 order of magnitude below this threshold (0.07 kg/m3), which generated a fast (1.5 m/s), 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.
AB - 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/m3. Here we present direct observations of an exceptionally dilute river plume, with sediment concentrations 1 order of magnitude below this threshold (0.07 kg/m3), which generated a fast (1.5 m/s), 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.
UR - http://www.scopus.com/inward/record.url?scp=85074831727&partnerID=8YFLogxK
U2 - 10.1029/2019GL084526
DO - 10.1029/2019GL084526
M3 - Article
AN - SCOPUS:85074831727
SN - 0094-8276
VL - 46
SP - 11310
EP - 11320
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 20
ER -