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Pattier, France; Loncke, L.; Gaullier, V.; Basile, C.; Maillard, Alexandre; Imbert, Patrice; Roest, Walter; Vendeville, B. C.; Patriat, Martin; Loubrieu, Benoit. |
The eastern Demerara Plateau offshore French Guiana was surveyed in 2003 during the GUYAPLAC cruise (multibeam bathymetry and acoustic imagery, 6-channel seismic reflection and 3.5 kHz echo-sounding). The data show the "post-transform" Cenozoic that the series located on the outer part of the plateau (below c. 2000 m) contain at least twelve stacked mass transport deposits (MTDs) that have recorded a history of large-scale slope failure, as well as two main normal fault sets that provide possible pathways for upward fluid migration through the series, reaching at high as the uppermost MTDs. Seabed data show that the area above the failures is characterized by circular-to-elongate (slope-parallel) depressions interpreted as fluid seeps (pockmarks), some of... |
Tipo: Text |
Palavras-chave: Fluid ascent; Pockmarks; MTDs; Transform margin; Demerara Plateau. |
Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00157/26850/25316.pdf |
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Pattier, France; Loncke, L.; Imbert, Patrice; Gaullier, V.; Basile, C.; Maillard, Alexandre; Roest, Walter; Patriat, Martin; Vendeville, B. C.; Marsset, Tania; Bayon, Germain; Cathalot, Cecile; Caprais, Jean-claude; Bermell, Sylvain; Sotin, Christine; Hebert, Bertil; Mercier De Lepinay, Marion; Lebrun, J. F.; Marcaillou, B.; Heuret, A.; Droz, Laurence; Graindorge, David; Poetisi, E.; Berrenstein, H.. |
The Demerara plateau, located offshore French Guiana and Suriname, is part of a passive transform continental margin particularly prone to develop slope instabilities, probably in relation to the presence of a free distal border along its steep continental slope. Slope failure occurred at different periods (Cretaceous to Neogene) and shows an overall retrogressive evolution through time. Upslope these failure headscarp, an enigmatic regional MioPliocene unconformity has been discovered through the interpretation of new academic and industrial datasets. The aim of this work is to describe and understand the origin of this surface. Our analysis shows that this unconformity is made of a series of valleys that cross-cut sedimentary strata. Each one of these... |
Tipo: Text |
Palavras-chave: Unconformity; Hydrate pockmark; Slide; Contourite; Valley; Canyon; Demerara plateau. |
Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00271/38193/36735.pdf |
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