Echofacies interpretation of Pleistocene to Holocene contourites on the Demerara plateau and abyssal plain

Type Article
Date 2021-05
Language English
Author(s) Tallobre Cédric1, Loncke Lies1, Droz Laurence2, Marsset TaniaORCID3, Uusõue Mirjam4, Roest WalterORCID3, Fanget Anne-Sophie1, Bassetti Maria-Angela1, Giresse Pierre1, Bayon Germain3
Affiliation(s) 1 : Université de Perpignan Via Domitia, Centre de Formation et de Recherche sur les Environnements Méditerranéens (CEFREM), UMR 5110, Perpignan, France..
2 : Université de Bretagne Occidentale (UBO)/UMR 6538 du CNRS Domaines Océaniques, Plouzané, France..
3 : IFREMER, Unité de Recherche Géosciences Marines, Plouzané, France..
4 : Tartu Observatory, Observatooriumi 1, Tõravere, 61602 Tartumaa, Estonia..
Source Interpretation-a Journal Of Subsurface Characterization (2324-8858) (Society of Exploration Geophysicists), 2021-05 , Vol. 9 , N. 2 , P. SB49-SB65
DOI 10.1190/INT-2020-0159.1
WOS© Times Cited 1

Off French Guiana and Surinam, NADW and AABW oceanic currents contour the Demerara marginal plateau, which promotes the formation of contourites. We have studied these contourites thanks to a new compilation of high-resolution sub-bottom profiles calibrated by sedimentary cores. The echo-facies and isopach maps we constructed highlight a sedimentary distribution parallel to the isobaths. The presence of moats along the slope is confirmed by the observation of parallel, elongated, sedimentary depleted zones and echo-facies strongly affected by diffraction hyperbola and transparent echo-facies. We interpret these features to be related to eroded slopes and Mass Transport Deposits. In contrast, the sedimentary drifts we mapped are characterized by elongated and thick slope-parallel depocentres displaying bedded echo-facies with wave-like bedforms. According to our interpretation, they result from interactions between currents and the seafloor. Seismic wipe-outs frequently affect those drifts, possibly resulting from high water or organic contents.

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Tallobre Cédric, Loncke Lies, Droz Laurence, Marsset Tania, Uusõue Mirjam, Roest Walter, Fanget Anne-Sophie, Bassetti Maria-Angela, Giresse Pierre, Bayon Germain (2021). Echofacies interpretation of Pleistocene to Holocene contourites on the Demerara plateau and abyssal plain. Interpretation-a Journal Of Subsurface Characterization, 9(2), SB49-SB65. Publisher's official version : , Open Access version :