Geomorphology of a modern carbonate slope system and associated sedimentary processes: Example of the giant Great Abaco Canyon, Bahamas

Type Article
Date 2021-01
Language English
Author(s) Recouvreur Audrey1, Fabregas Natacha2, Mulder Thierry1, Hanquiez Vincent1, Fauquembergue Kelly1, Tournadour Elsa3, 4, Gillet Hervé1, Borgomano Jean5, Poli Emmanuelle, Kucharski Jean‐baptiste1, Wilk Stanislas1
Affiliation(s) 1 : Université de Bordeaux EPOC UMR 5805 33615 Pessac Cedex ,France
2 : Department of Earth Science University of Bergen Allégaten 41 5007 Bergen ,Norway
3 : IFREMER Géosciences Marines CS 10070, 29280 Plouzané, France
4 : Geological Survey of New Caledonia DIMENC BP 465 98845 Nouméa New Caledonia ,France
5 : Centre Européen de Recherche et d’Enseignement de Géosciences de l’Environnement Aix‐Marseille Université – CNRS (UMR7330) – IRD (UMR 161) – COLLEGE de France – USC INRA – OSU – Institut PYTHEAS – Technopole Environnement Arbois‐Méditerranée BP80 13545 Aix en Provence Marseille CEDEX 04 ,France
Source Sedimentology (0037-0746) (Wiley), 2021-01 , Vol. 68 , N. 1 , P. 266-293
DOI 10.1111/sed.12777
Keyword(s) Backscatter, Bahamas, carbonate slope, echofacies, giant canyon, sea floor morphology, sedimentary processes
Abstract

The large acoustic data set acquired during the Carambar cruises is composed of high resolution bathymetry, backscatter data and very‐high resolution seismic lines which allow for an overview of the morphology and sediment transfer processes from the shallow upper slope to the abyssal plain of a modern carbonate system: the north‐eastern slope of the Little Bahama Bank. Surficial distribution of the acoustic facies and echofacies reflects a wide variety of sedimentary processes along and across the slope. The western sector of the Little Bahama Bank is dominated by depositional processes whereas its eastern sector, which is incised in the lower slope by giant canyons, is affected by erosion and bypass processes. Datasets suggest that currents play an important role both along‐slope sedimentary processes and in the abyssal plain. The Antilles Current appears to affect a large part of the middle and lower slopes. The absence of sizable present‐day channel/levée complexes or lobes at the mouth of the canyon – revealed by the bathymetric map – indicates that the southward flowing Deep Western Boundary Current influences modern abyssal sediment deposition. Based on depositional processes and indicators of canyon maturity observed in facies distribution, the current study proposes that differential subsidence affects the eastern versus western part of the bank. The morphology of the Great Abaco Canyon and Little Abaco Canyon, which extends parallel to the platform, and the Little Bahama Bank slope appears to be related to the Great Abaco Fracture Zone.

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Recouvreur Audrey, Fabregas Natacha, Mulder Thierry, Hanquiez Vincent, Fauquembergue Kelly, Tournadour Elsa, Gillet Hervé, Borgomano Jean, Poli Emmanuelle, Kucharski Jean‐baptiste, Wilk Stanislas (2021). Geomorphology of a modern carbonate slope system and associated sedimentary processes: Example of the giant Great Abaco Canyon, Bahamas. Sedimentology, 68(1), 266-293. Publisher's official version : https://doi.org/10.1111/sed.12777 , Open Access version : https://archimer.ifremer.fr/doc/00636/74787/