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Hage, Sophie; Cartigny, Matthieu J.b.; Sumner, Esther J.; Clare, Michael A.; Hughes Clarke, John E.; Talling, Peter J.; Lintern, D. Gwyn; Simmons, Stephen M.; Silva Jacinto, Ricardo; Vellinga, Age J.; Allin, Joshua R.; Azpiroz‐zabala, Maria; Gales, Jenny A.; Hizzett, Jamie L.; Hunt, James E.; Mozzato, Alessandro; Parsons, Daniel R.; Pope, Ed L.; Stacey, Cooper D.; Symons, William O.; Vardy, Mark E.; Watts, Camilla. |
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... |
Tipo: Text |
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Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00514/62594/66952.pdf |
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Callard, S. Louise; Cofaigh, Colm O.; Benetti, Sara; Chiverrell, Richard C.; Van Landeghem, Katrien J. J.; Saher, Margot H.; Gales, Jenny A.; Small, David; Clark, Chris D.; Stephen, J. Livingstone; Fabel, Derek; Moreton, Steven G.. |
During the Last Glacial Maximum (LGM) the marine-terminating Barra Fan Ice Stream (BFIS), a major conduit of the British Irish Ice Sheet (BITS), drained much of western Scotland and northwest Ireland with ice streaming onto the continental shelf of the Malin Sea. The extent and retreat history of this ice stream across the shelf, until now, is not well known. In particular, geochronological constraints on the history of this ice stream have thus far been restricted to deep-sea cores or terrestrial cosmogenic nuclide dating onshore, with ages across the shelf absent. To understand the possible external forcing factors acting on this marine terminating ice stream during retreat, improved geochronological constraint on its deglaciation is necessary. Here, we... |
Tipo: Text |
Palavras-chave: British-Irish Ice Sheet; Glacimarine; Last glacial maximum; Radiocarbon dating; Ice-sheet retreat; Grounding-zone wedges. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00504/61588/65891.pdf |
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