The Last Glacial Maximum Balearic Abyssal Plain Megabed revisited

Type Article
Date 2020-05
Language English
Author(s) Cattaneo AntonioORCID1, Badhani ShrayORCID1, Caradonna Cristina3, Bellucci Massimo2, Leroux EstelleORCID1, Babonneau Nathalie1, Garziglia Sebastien1, Poort Jeffrey4, Akhmanov Grigorii G.5, Bayon Germain1, Dennielou BernardORCID1, Jouet Gwenael1, Migeon Sebastien6, Rabineau MarinaORCID9, Droz Laurence8, Clare Michael7
Affiliation(s) 1 : IFREMER, Géosciences Marines, Plouzané, France
2 : UMR 6538 Géosciences Océan, Université de Brest, France
3 : Università di Trieste, Italy
4 : UMR 7193 ISTeP, Sorbonne Université, Paris, France
5 : Lomonosov Moscow State University, Moscow, Russian Federation, France
6 : UMR7329, GEOAZUR, Valbonne, France
7 : National Oceanography Centre, University of Southampton, United Kingdom
8 : IFREMER, Géosciences Marines, Plouzané, France
9 : UMR 6538 Géosciences Océan, Université de Brest, France
Source Geological Society, London, Special Publications (0305-8719) (Geological Society of London), 2020-05 , Vol. 500 , P. 341-357
DOI 10.1144/SP500-2019-188
Note From: Georgiopoulou, A., Amy, L. A., Benetti, S., Chaytor, J. D., Clare, M. A., Gamboa, D., Haughton, P. D. W., Moernaut, J. and Mountjoy, J. J. (eds) 2020. Subaqueous Mass Movements and their Consequences: Advances in Process Understanding, Monitoring and Hazard Assessments. Geological Society, London, Special Publications, 500, 341–357. First published online May 14, 2020, https://doi.org/10.1144/SP500-2019-188
Abstract

Megabeds are thick sedimentary layers extending over thousands square kilometres in deep sea basins and are thought to result from large slope failures triggered by major external events. Such deposits have been found in at least three areas of the Mediterranean Sea. Although their discovery dates back to the early 1980s, many questions remain, concerning their initiation, source area, extent, and the nature of their emplacement. One of the largest previously documented megabeds was emplaced during the Last Glacial Maximum across the Balearic Abyssal Plain with a thickness of 8-10 m in water depths of up to 2800 m.

New 3.5 kHz sub-bottom profiles and sediment cores provide greater constraint on the lateral variability of the megabed and allow to map it beyond previous estimates, with a revised areal extent up to 90,000-100,000 km2. Megabed terminations show gradual pinch-out to the West and an abrupt eastward termination against the Sardinia steep margin. The megabed presents both in seismic profiles and in sediment cores a tripartite subdivision likely corresponding to changes in flow regimes across the basin with a central area of sandy facies and erosional base oriented NNE-SSW allowing renewed discussions about sources and trigger of the megabed.

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Cattaneo Antonio, Badhani Shray, Caradonna Cristina, Bellucci Massimo, Leroux Estelle, Babonneau Nathalie, Garziglia Sebastien, Poort Jeffrey, Akhmanov Grigorii G., Bayon Germain, Dennielou Bernard, Jouet Gwenael, Migeon Sebastien, Rabineau Marina, Droz Laurence, Clare Michael (2020). The Last Glacial Maximum Balearic Abyssal Plain Megabed revisited. Geological Society, London, Special Publications, 500, 341-357. Publisher's official version : https://doi.org/10.1144/SP500-2019-188 , Open Access version : https://archimer.ifremer.fr/doc/00614/72597/