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

Type Article
Date 2016-09
Language English
Author(s) Loncke L.1, Maillard A.2, Basile C.3, Roest WalterORCID4, Bayon Germain4, Gaullier V.5, Pattier France1, Mercier De Lépinay Marion1, Grall Celine1, Droz L.6, Marsset TaniaORCID4, Giresse P.1, Caprais Jean-Claude4, Cathalot CecileORCID4, Graindorge D.6, Heuret A.7, Lebrun J. F.7, Bermell Sylvain4, Marcaillou B.7, Sotin C.1, Hebert B.1, Patriat MartinORCID4, Bassetti M. A.1, Tallobre Cedric1, Buscail R.1, Durrieu De Madron X.1, Bourrin F.1
Affiliation(s) 1 : Université de Perpignan Via Domitia, Centre de Formation et de Recherche sur les Environnements Méditerranéens, UMR 5110, 52 avenue Paul Alduy, F-66860, Perpignan, France
2 : GET–OMP–Université Paul Sabatier, 14 avenue E. Belin, 31400, Toulouse, France
3 : ISTerre, UMR–CNRS 5275, Observatoire des Sciences de l'Univers de Grenoble, Université Joseph Fourier, Maison des Géosciences, 1381 rue de la Piscine, 38400 St Martin d'Hères, France
4 : Ifremer, Centre de Brest, Institut Carnot–Ifremer EDROME, UR Géosciences Marines, BP 70, 29280 Plouzané, France
5 : Université de Lille 1, UMR 8217 – Géosystèmes, Bâtiment S.N.5, Cité Scientifique, 59655 Villeneuve d'Ascq Cedex, France
6 : Université de Bretagne Occidentale (UBO)/UMR 6538 du CNRS ‘Domaines Oceaniques’, Institut Universitaire Européen de la Mer (IUEM), Technopole Brest Iroise, Place Nicolas Copernic, 29280 Plouzané, France
7 : Université des Antilles et de la Guyane, Laboratoire Large, Campus Fouillole, BP 592, 97157 Pointe à Pitre, France
Source Geological Society, London, Special Publications (0305-8719) (Geological Society of London), 2016-09 , Vol. 431 , N. 1 , P. 179-197
DOI 10.1144/SP431.7
Note Geological Society, London, Special Publications. Volume 431, 2016. https://doi.org/10.1144/SP431 Transform Margins: Development, Controls and Petroleum Systems Edited by: M. Nemčok, EGI, University of Utah, USA, EGI Laboratory at SAV, Slovakia S. Rybár, EGI Laboratory at SAV, Slovakia, Comenius University, Slovakia S. T. Sinha, Reliance Industries Ltd, India S. A. Hermeston, White Rose Energy Ventures, UK and L. Ledvényiová, EGI Laboratory at SAV, Slovakia, Comenius University, Slovakia
Abstract

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.

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Loncke L., Maillard A., Basile C., Roest Walter, Bayon Germain, Gaullier V., Pattier France, Mercier De Lépinay Marion, Grall Celine, Droz L., Marsset Tania, Giresse P., Caprais Jean-Claude, Cathalot Cecile, Graindorge D., Heuret A., Lebrun J. F., Bermell Sylvain, Marcaillou B., Sotin C., Hebert B., Patriat Martin, Bassetti M. A., Tallobre Cedric, Buscail R., Durrieu De Madron X., Bourrin F. (2016). Structure of the Demerara passive-transform margin and associated sedimentary processes. Initial results from the IGUANES cruise. Geological Society, London, Special Publications, 431(1), 179-197. Publisher's official version : https://doi.org/10.1144/SP431.7 , Open Access version : https://archimer.ifremer.fr/doc/00428/53942/