Structure of the Demerara passive-transform margin and associated sedimentary processes. Initial results from the IGUANES cruise

International audience he IGUANES cruise took place in May 2013 on the R/V L'Atalante along the Demerara passive transform margin off French Guiana and Surinam. Seismic, multibeam and chirp acquisitions were made. Piston cores were collected for pore geochemistry and sedimentology. A mooring wa...

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Published in:Geological Society, London, Special Publications
Main Authors: Loncke, L., Maillard, A., Basile, C., Roest, R., Bayon, G., Gaullier, V., Pattier, F., Mercier de Lépinay, M., Grall, C., Droz, L., Marsset, T., Giresse, P., Caprais, C., Cathalot, C., Graindorge, D., Heuret, A., Lebrun, F., Bermell, S., Marcaillou, B., Sotin, C., Hebert, B., Patriat, M., Bassetti, M., Tallobre, C., Buscail, R., Durrieu de Madron, X., Bourrin, F.
Other Authors: Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement IRD : UR219-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Géosystèmes - UMR 8217, Université de Lille, Sciences et Technologies-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Recherche en Géosciences et Energies UR2_1 (LARGE), Université des Antilles (UA), Centre de formation et de recherche en environnement marin (CEFREM)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2016
Subjects:
Online Access:https://univ-perp.hal.science/hal-01741165
https://univ-perp.hal.science/hal-01741165/document
https://univ-perp.hal.science/hal-01741165/file/55285.pdf
https://doi.org/10.1144/SP431.7
Description
Summary:International audience he IGUANES cruise took place in May 2013 on the R/V L'Atalante along the Demerara passive transform margin off French Guiana and Surinam. Seismic, multibeam and chirp acquisitions were made. Piston cores were collected for pore geochemistry and sedimentology. A mooring was deployed on the sea-bottom for 10 months (temperature, salinity, turbidity and current measurements). This new dataset highlights the lateral variability of the 350 km-long Guiana–Surinam transform margin due to the presence of a releasing bend between two transform segments. The adjacent Demerara Plateau is affected by a 350 km-long giant slide complex. This complex initiated in Cretaceous times and was regularly reactivated until recent times. Since the Miocene, contourite processes seem to be active due to the onset of the North Atlantic Deep Water (NADW) bottom current. A main NADW water vein flows towards SE, eroding slide headscarps and allowing the deposition of contourite drifts. Numerous depressions looking like comet tails or comet scours record this flow. Some of those were interpreted before the cruise as active pockmarks. Pore geochemistry and core analysis do not show any evidence of present-day gas seepage.