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| Registros recuperados: 10 | |
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| Minshull, T. A.; Westbrook, Graham; Weitemeyer, K. A.; Sinha, M. C.; Goswami, B. K.; Marsset, Bruno. |
| Methane hydrate—a solid substance in which methane is trapped within ice‐like crystals—is stable at low temperatures and high pressures and may be destabilized by ocean warming on both geological and human time scales. Methane is a powerful greenhouse gas, and methane released from hydrate provides a potential positive feedback mechanism in global climate change [e.g., Archer and Buffett, 2005]—in theory, the more methane is released by the hydrates, the warmer the climate gets, causing the ocean to warm and release more methane. However, methane escaping from the seabed is oxidized and dissolved in the ocean, and insufficient methane may reach the atmosphere to affect the climate significantly. Its importance for climate change therefore depends on... |
| Tipo: Text |
Palavras-chave: Methane hydrate; Svalbard; Sea floor; Seismic; Electromagnetic; Arctic. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00451/56262/57832.pdf |
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| Blouin, Arthur; Imbert, Patrice; Sultan, Nabil; Callot, Jean-paul. |
| The morphology of mud volcanoes (MV) has been extensively studied over the last few decades. Although recent research has begun to focus on deep processes and structures, little is known about mud generation mechanisms. This study aims to investigate the feeder system and formation of an active kilometer‐scale MV by relying on a 3‐D seismic survey and an in‐situ dataset on the Absheron anticline (South Caspian Basin). Seismic data show a depleted area in the Anhydritic Surakhany Formation (ASF), whose mineralogical composition fits with surface mud. Well data show that the ASF is a succession of evaporitic beds and low temperature shales near its fracture pressure. Biostratigraphic analysis confirms a Pliocene origin for the mud, suggesting that the ASF... |
| Tipo: Text |
Palavras-chave: Mud volcano; Pore pressure; Methane; Modeling; Seismic. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00481/59304/62057.pdf |
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| Colin, Florent; Ker, Stephan; Riboulot, Vincent; Sultan, Nabil. |
| Gas hydrate (GH) systems constitute methane sinks sensitive to environmental changes such as pressure, temperature, and salinity. It remains a matter of debate as to whether the large GH system of the Black Sea has reached a steady state since the last glacial maximum (LGM). We report on an irregular free gas distribution in specific sediment layers marking an irregular bottom‐simulating reflector (BSR). This anomalous free gas distribution revealed by very high resolution seismic images, acquired by a deep‐towed multichannel seismic system, might be evidence of an on‐going migration of the base of the GH stability zone (GHSZ). We show that the reequilibrium is not occurring homogeneously as overpressure from hydrate dissociation slows their decomposition... |
| Tipo: Text |
Palavras-chave: Hydrates; Seismic; Very high resolution; Dissociation; Black Sea. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00652/76430/77526.pdf |
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| Dennielou, Bernard; Droz, Laurence; Babonneau, Nathalie; Jacq, Celine; Bonnel, Cedric; Picot, Marie; Le Saout, Morgane; Saout, Yohan; Bez, Martine; Savoye, Bruno; Olu, Karine; Rabouille, Christophe. |
| The detailed structure and composition of turbiditic channel-mouth lobes is still largely unknown because they commonly lie at abyssal water depths, are very thin and are therefore beyond the resolution of hull-mound acoustic tools. The morphology, structure and composition of the Congo turbiditic channel-mouth lobe complex (90×40 km; 2525 km2) were investigated with hull-mounted swath bathymetry, air gun seismics, 3.5 kHz sub-bottom profiler, sediment piston cores and also with high-resolution multibeam bathymetry and video acquired with a Remote Operating Vehicle (ROV). The lobe complex lies 760 km off the Congo River mouth in the Angola abyssal plain between 4740 and 5030 m deep. It is active and is fed by turbidity currents that deposit several... |
| Tipo: Text |
Palavras-chave: Congo deep-sea fan; Lobe; Lobe complex; Channel; Channel-Lobe Transition Zone; Angola basin; Slump; Slide; Debrite; Turbidite; ROV; Bathymetry; Seismic; Sediment core. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00378/48976/49383.pdf |
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| Lericolais, Gilles; Algan, Oya; Morigi, Caterina; Okay, Seda; Kirci-elmas, Elmas; Cifci, Gunay. |
| Since the preliminary mapping of the northern Bosphorus outlet of the Black Sea continental shelf by the 90’s NATO project, an important data set bringing morphological, seismic and sedimentological information is now available to describe there a shallow fan system consisting of a main channel and short distributary branches, levees, and sediment waves, correlative to a southern source flowing to the north. This paper brings complementary quantitative data from landscape at the eastern and western shelf area of the shallow fan system. It confirms that the Bosphorus outlet fan preserved on the shelf surface provides an important record of surface water flow. To deduce the history of the Marmara/Black Sea last connexion, it is fundamental to understand how... |
| Tipo: Text |
Palavras-chave: Bosphorus; Black Sea; Seismic; Sediment cores; Multibeam bathymetry; Shallow fan. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00501/61254/64838.pdf |
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| Registros recuperados: 10 | |
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