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| Lericolais, Gilles; Bulois, C.; Gillet, Herve; Guichard, F.. |
| This paper presents a 3D geometric interpretation of very high resolution seismic Chirp profiles acquired on the Romanian shelf during ASSEMBLAGE European Project. The results provide a solid record of the Black Sea Last Glacial Maximum (LGM) water level fluctuations. This pseudo-3D seismic interpretation shows that the Black Sea lacustrine shelf deposits form a significant basinward-prograding wedge system. on top of these prograding sequences is a set of sand dunes that delineates a wave cut-terrace like feature around the isobath -100 m. Landward of this dune field are small depressions containing barkhan-like bodies. The upper part of the last prograding sequence is incised by anastomosed channels which end in the Danube (Viteaz) canyon which are also... |
| Tipo: Text |
Palavras-chave: Black Sea; Enclosed basin; Forced regression; Rapid transgression; Sea level changes. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6587.pdf |
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| Mazieres, Alais; Gillet, Herve; Castelle, Bruno; Mulder, Thierry; Guyot, Corentin; Garlan, Thierry; Mallet, Cyril. |
| In this study, the Capbreton canyon head, just off the coast, is investigated using high-resolution multibeam bathymetry datasets, sediment samples and numerical modeling. The HR bathymetry analysis reveals a morphological connection between the longshore trough and the head of the canyon. The analysis of recent sediment samples shows a clear correlation between the sediment of the canyon head and that of the nearshore. Hydrodynamic modeling (a coupled wave-flow model) shows that for high-energy waves, the rotational nature of surf-zone circulation reverses and wave-induced currents have the potential to transport large quantities of nearshore sands toward the canyon head. All these arguments support the assumption that the canyon head captures a part of... |
| Tipo: Text |
Palavras-chave: Longshore drift; Submarine canyon; Capbreton; Hydrodynamic modeling; Sediment transport. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00180/29118/27524.pdf |
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| Guiastrennec-faugas, Lea; Gillet, Herve; Peakall, Jeff; Dennielou, Bernard; Gaillot, Arnaud; Jacinto, Ricardo Silva. |
| Submarine channels are the main conduits and intermediate stores for sediment transport into the deep sea, including organics, pollutants, and microplastics. Key drivers of morphological change in channels are upstream-migrating knickpoints whose initiation has typically been linked to episodic processes such as avulsion, bend cutoff, and tectonics. The initiation of knickpoints in submarine channels has never been described, and questions remain about their evolution. Sedimentary and flow processes enabling the maintenance of such features in non-lithified substrates are also poorly documented. Repeated high-resolution multibeam bathymetry between 2012 and 2018 in the Capbreton submarine canyon (southeastern Bay of Biscay, offshore France) demonstrates... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00687/79926/82830.pdf |
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| Gillet, Herve; Lericolais, Gilles; Rehault, Jean Pierre. |
| In 1975, sediment cores from leg DSDP 42b (sites 380A and 381) revealed a thin sediment layer in the Black Sea basin which points to a shallow water environment at the Miocene-Pliocene boundary. With these facts and in the wake of hypothesis of the Messinian Salinity Crisis (MSC), it was proposed that the Black Sea, like the Mediterranean Sea, suffered a desiccation period at the end of the Messinian (Hsu, K.J. and Giovanoli, F., 1979. Messinian event in the Black Sea. Palaeogeography, Palaeoclimatology, Palaeoecology, 29: 75-93). Whereas the main topics of the MSC in the Mediterranean Sea is now widely accepted, the lack of evidence for a Messinian erosional surface in the Black Sea left the debate about the Messinian desiccation of this basin open until... |
| Tipo: Text |
Palavras-chave: Messinian salinity crisis; Seismic stratigraphy; Messinian erosional surface; Black Sea. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3324.pdf |
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| Popescu, Irina; De Batist, Marc; Lericolais, Gilles; Nouze, Herve; Poort, Jeffrey; Panin, Nicolae; Versteeg, Wim; Gillet, Herve. |
| A previously unknown pattern of multiple bottom-simulating reflections (BSRs) occurs on high-resolution reflection seismic data in the Danube deep-sea fan, associated with acoustic features indicating free gas. Our study provides evidence that this pattern is developed in relation with the architecture of distinct channel-levee systems of the Danube fan. Channel-levee systems hosting multiple BSRs act as relatively sealed gas-bearing systems whose top is situated above the base of the gas hydrate stability zone (BGHSZ). Inside these systems, free gas accumulates below the BGHSZ under a combined lithological, structural and stratigraphical control. The uppermost BSR marks the current equilibrium BGHSZ, for a gas composition of more than 99% methane.... |
| Tipo: Text |
Palavras-chave: Black Sea; Deep sea fan; Seismic data; Gas; Gas hydrates; Bottom simulating reflections. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1210.pdf |
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| Popescu, Irina; Lericolais, Gilles; Panin, Nicolae; De Batist, Marc De; Gillet, Herve. |
| This study is a synthesis of gas-related features in recent sediments across the western Black Sea basin. The investigation is based on an extensive seismic dataset, and integrates published information from previous local studies. Our data reveal widespread occurrences of seismic facies indicating free gas in sediments and gas escape in the water column. The presence of gas hydrates is inferred from bottom-simulating reflections (BSRs). The distribution of the gas facies shows (1) major gas accumulations close to the seafloor in the coastal area and along the shelfbreak, (2) ubiquitous gas migration from the deeper subsurface on the shelf and (3) gas hydrate occurrences on the lower slope (below 750 m water depth). The coastal and shelfbreak shallow gas... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2615.pdf |
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| Suc, Jean-pierre; Gillet, Herve; Cagatay, M. Namik; Popescu, Speranta-maria; Lericolais, Gilles; Armijo, Rolando; Melinte-dobrinescu, Mihaela Carmen; Sen, Sevket; Clauzon, Georges; Sakinc, Mehmet; Zabci, Cengiz; Ucarkus, Gulsen; Meyer, Bertrand; Cakir, Ziyadin; Karakas, Cagil; Jouannic, Gwenael; Macalet, Rodica. |
| The two sides of the Strandja Sill show a highly discontinuous stratigraphic succession since the Late Oligocene. This area, together with the Sea of Marmara Basin, is usually proposed as the gateway for the Paratethyan freshwaters and organisms that constituted the Lago Mare facies in the Mediterranean Sea during the Messinian Salinity Crisis (MSC). Our investigations involving new field observations and datings, together with previous studies, suggest that the sill has possibly experienced such a connection at around 8 Ma, i.e. significantly before the crisis. The proposal of a sea-level drop of the Black Sea before 7 Ma is not supported by our data on dinoflagellate cysts. Consistency of calcareous nannofossil succession at DSDP Site 380 is reinforced,... |
| Tipo: Text |
Palavras-chave: Mediterranean-Paratethys connection; Onshore-offshore stratigraphy; Messinian Salinity Crisis; Erosion; Fluvial network. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00251/36217/34768.pdf |
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