Formation and evolution of glauconite in the Demerara Contourite depositional system related to NADW circulation changes during late Quaternary (French Guiana)

Type Article
Date 2019-06
Language English
Author(s) Tallobre Cédric1, 2, Giresse Pierre1, 2, Bassetti Maria-Angela1, 2, Loncke Lies1, 2, Bayon Germain3, Buscail Roselyne1, 2, Tudryn Alina4, Zaragosi Sébastien5
Affiliation(s) 1 : Univ. Perpignan Via Domitia, Centre de Formation et de Recherche sur les Environnements Méditerranéens (CEFREM), UMR 5110, 52 Avenue Paul Alduy, 66860, Perpignan, France
2 : CNRS, Centre de Formation et de Recherche sur les Environnements Méditerranéens (CEFREM), UMR 5110, 52 Avenue Paul Alduy, 66860, Perpignan, France
3 : IFREMER, Unité de Recherche Géosciences Marines, 29280, Plouzané, France
4 : GEOPS, Univ. Paris-Sud, CNRS, Université Paris-Saclay, Rue du Belvédère, Bât. 504-509, 91405, Orsay, France
5 : Université de Bordeaux, Environnements et Paléoenvironnements Océaniques et Continentaux, UMR CNRS 5805 EPOC, Allée Geoffroy Saint-Hilaire, CS 50023 - 33615, Pessac cedex, France
Source Journal Of South American Earth Sciences (0895-9811) (Elsevier BV), 2019-06 , Vol. 92 , P. 167-183
DOI 10.1016/j.jsames.2019.03.011
WOS© Times Cited 8
Keyword(s) Marginal plateau, Contourite, Glauconite, Demerara plateau
Abstract

The Demerara Plateau is a marginal plateau which forms a bathymetric relief on the sea floor. Here, contourite deposits have been studied in detail, following the recent discovery of contourite sequences likely related to the bottom currents and linked both to contour current and peculiar sea-floor morphology. A chronostratigraphic framework, based on δ18O relative variations and palaeomagnetic events in sediment cores allows correlating sediment processes to current intensity changes and major climate phases (glacial or interglacial). The studied sediments are enriched in glauconitic grains. In addition, the glauconite mineralogical maturity can easily correlate to low sedimentation rate and slightly energetic bottom currents on the seafloor. Based on these data and using the glauconitic authigenic mineral as proxy for inferring the degree of winnowing at the sediment-water interface, we might put forward the hypothesis that the intensity of NADW is higher during the glacial stages and lower during interglacial periods.

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Tallobre Cédric, Giresse Pierre, Bassetti Maria-Angela, Loncke Lies, Bayon Germain, Buscail Roselyne, Tudryn Alina, Zaragosi Sébastien (2019). Formation and evolution of glauconite in the Demerara Contourite depositional system related to NADW circulation changes during late Quaternary (French Guiana). Journal Of South American Earth Sciences, 92, 167-183. Publisher's official version : https://doi.org/10.1016/j.jsames.2019.03.011 , Open Access version : https://archimer.ifremer.fr/doc/00485/59665/