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| Collot, Julien; Patriat, Martin; Etienne, S.; Rouillard, P.; Soetaert, F.; Juan, C.; Marcaillou, B.; Palazzin, G.; Clerc, C.; Maurizot, P.; Pattier, F; Tournadour, E.; Sevin, B.; Privat, A.. |
| Classically, deepwater fold-and-thrust belts are classified in two main types, depending if they result from near- or far-field stresses and the understanding of their driving and triggering mechanism is poorly known. We present a geophysical dataset off the western margin of New Caledonia (SW Pacific) that reveals deformed structures of a deepwater fold-and-thrust belt that we interpret as a near-field gravity-driven system, which is not located at a rifted passive margin. The main factor triggering deformation is inferred to be oversteepening of the margin slope by post-obduction isostatic rebound. Onshore erosion of abnormally-dense obducted material, combined with sediment loading in the adjacent basin, has induced vertical motions that have caused... |
| Tipo: Text |
Palavras-chave: Deepwater fold-and-thrust belt; Obduction; Isostasy. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00405/51614/52162.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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| Collot, Julien; Migeon, Sebastien; Spence, G.; Legonidec, Y.; Marcaillou, B.; Schneider, J.-l.; Michaud, F.; Alvarado, A.; Lebrun, J.-f.; Sosson, M.; Pazmino, A.. |
| cuador and southwest (SW) Colombia suffered widespread damage during the twentieth century as a result of some of the greatest subduction earthquakes and associated tsunamis ever recorded. In 1906, the Ecuador‐SW Columbia margin, located at the transition between the continent and deep ocean, ruptured over a 500‐kilometer length as a single great (Mw = 8.8) subduction earthquake (Figure 1a) [Kelleher, 1972]. The 1906 rupture zone was partially reactivated in 1942, 1958, and 1979 by earthquakes of Mw 7.7 to 8.2 (Figure 1b), with 100‐200 kilometerlong rupture zones [Beck and Ruff, 1984]. Such considerable variation in earthquake rupture length and magnitude in this area's seismic cycles during the last century has raised questions about the nature and... |
| Tipo: Text |
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| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00451/56257/57826.pdf |
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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.. |
| 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... |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00428/53942/55285.pdf |
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| Laurencin, M.; Marcaillou, B.; Graindorge, David; Lebrun, J.‐f.; Klingelhoefer, Frauke; Boucard, M.; Laigle, M.; Lallemand, S.; Schenini, L.. |
| Strain partitioning related to oblique plate convergence has long been debated in Northern Lesser Antilles. Geophysical data acquired during the ANTITHESIS cruises highlight that the sinistral strike‐slip Bunce Fault develops along the vertical, long, and linear discontinuity between the sedimentary wedge and a more rigid backstop. The narrowness of the 20‐ to 30‐km‐wide accretionary wedge and its continuity over ~850 km is remarkable. The Bunce Fault extends as far south as 18.5°N where it anastomoses within the accretionary prism where the sharp increase in convergence obliquity possibly acts as a mechanical threshold. Surface traces related to subducting seamounts suggest that 80% of the lateral component of the convergent motion is taken up by internal... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00511/62291/66526.pdf |
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| Laurencin, Muriel; Marcaillou, B.; Graindorge, D.; Klingelhoefer, Frauke; Lallemand, S.; Laigle, M.; Lebrun, J. -f.. |
| The influence of the highly oblique plate convergence at the northern Lesser Antilles onto the margin strain partitioning and deformation pattern, although frequently invoked, has never been clearly imaged. The Anegada Passage is a set of basins and deep valleys, regularly related to the southern boundary of the Puerto-Rico-Virgin-Islands (PRVI) microplate. Despite the publications of various tectonic models mostly based on bathymetric data, the tectonic origin and deformation of this Passage remains unconstrained in the absence of deep structure imaging. During cruises Antithesis 1 and 3 (2013 - 2016), we recorded the first deep multichannel seismic images and new multibeam data in the northern Lesser Antilles margin segment in order to shed a new light... |
| Tipo: Text |
Palavras-chave: Oblique subduction zone; Strain partitioning; Anegada Passage; Lesser Antilles margin; Multichannel seismic reflection. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00386/49710/50236.pdf |
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| Loncke, L.; Roest, Walter; Klingelhoefer, Frauke; Basile, C.; Graindorge, David; Heuret, A.; Marcaillou, B.; Museur, Thomas; Fanget, Anne-sophie; Mercier De Lépinay, M.. |
| Numerous submarine plateaus form highstanding bathymetric highs at continent to ocean transitions. Due to their proximity to continents, they have been frequently labelled “marginal plateaus”, although this term has not been clearly defined or associated with a specific geology or geodynamic process. Until now, these elevations have been interpreted as submerged thinned continental fragments detached from continents, basaltic buildups formed by hotspots, volcanic margins or oceanic plateaus. Many of these plateaus formed at transform margins connecting oceanic basins of contrasted ages. We propose for the first time to define and review a class of marginal plateaus related to a specific tectonic setting: “Transform Marginal Plateaus” (TMPs). Based on a... |
| Tipo: Text |
Palavras-chave: Transform marginal plateau; Transform margin; Volcanic margin; Large Igneous Province; Continental breakup; Paleoceanography; Land bridge; Gateway. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00512/62407/66663.pdf |
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