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| Registros recuperados: 56 | |
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| West, Bp; Wilcock, Wsd; Sempere, Jc; Geli, Louis. |
| Both geophysical and geochemical evidence suggests the presence of along-axis asthenospheric flow toward the Australian-Antarctic Discordance (AAD) beneath the Southeast Indian Ridge (SEIR). We use a three-dimensional, finite-volume formulation of viscous flow to investigate the structure of asthenospheric motion beneath the SEIR. Our results show that simple continental separation in either a constant- or variable-viscosity mantle without horizontal temperature gradients is unable to reproduce the inferred asthenospheric flow velocities and observed geographic distribution of the ''Indian'' and ''Pacific'' upper mantle isotopic provinces. The presence of a cooler, more viscous mantle directly beneath the AAD is necessary to reproduce observed constraints.... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00068/17903/15439.pdf |
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| Moulin, Maryline; Aslanian, Daniel; Olivet, Jean-louis; Contrucci, Isabelle; Matias, Luis; Geli, Louis; Klingelhoefer, Frauke; Nouze, Herve; Rehault, Jean Pierre; Unternehr, Patrick. |
| Deep penetration multichannel reflection and Ocean Bottom Seismometer wide-angle seismic data from the CongoAngola margin were collected in 2000 during the ZaïAngo cruise. These data help constrain the deep structure of the continental margin, the geometry of the pre-salt sediment layers and the geometry of the Aptian salt layer. Dating the deposition of the salt relative to the chronology of the margin formation is an issue of fundamental importance for reconstructing the evolution of the margin and for the understanding of the crustal thinning processes. The data show that the crust thins abruptly, from a 3040 km thickness to less than 10 km, over a lateral distance of less than 50 km. The transitional domain is a 180-km-wide basin. The pre-salt sediment... |
| Tipo: Text |
Palavras-chave: Deep seismic reflection and refraction; Sub salt imaging; Transitional domain; Crustal structure; Non volcanic passive continental margin. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/2005/publication-349.pdf |
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| Geli, Louis; Henry, P; Zitter, T; Dupre, Stephanie; Tryon, M; Cagatay, M; De Lepinay, B; Le Pichon, X; Sengor, A; Gorur, N; Natalin, B; Ucarkus, G; Oezeren, S; Volker, D; Gasperini, L; Burnard, P; Bourlange, S. |
| The submerged section of the North Anatolian fault within the Marmara Sea was investigated using acoustic techniques and submersible dives. Most gas emissions in the water column were found near the surface expression of known active faults. Gas emissions are unevenly distributed. The linear fault segment crossing the Central High and forming a seismic gap - as it has not ruptured since 1766, based on historical seismicity [Ambraseys, N.N., and Jackson, J.A., (2000), Seismicity of the Sea of Marmara (Turkey) since 1500, Geophys. J. Int., 141, (3), F1-F6. (doi:10.1046/j.1365-246x.2000.00137.x: Ambraseys, N., (2002), The seismic activity of the Marmara Region over the last 2000 years, Bull. Seism. Soc. Am., 92, 1-18; Parson, T., (2004), Recalculated... |
| Tipo: Text |
Palavras-chave: North Anatolian Fault; Marmara Sea; Gas emission; Fluids; Seismicity. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4681.pdf |
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| Klingelhofer, Frauke; Geli, Louis; Matias, Luis; Steinsland, N; Mohr, J. |
| A series of eight high-resolution seismic refraction profiles from the ultra-slow spreading (16 mm yr(-1) full spreading rate) Mohns Ridge in the Norwegian-Greenland Sea has been treated with modern inversion methods. The profiles were shot parallel to the ridge at an off-axis distance of 0-135 km corresponding to crustal ages of 0-22 Ma. The resulting models are constrained by synthetic seismograms and gravity modelling.The crustal thickness in all profiles is well below the global average for typical oceanic crust, and shows a high variability with a mean thickness of 4.0 +/- 0.5 km. This is mainly due to a very thin and variable lower crustal layer (Layer 3). Generally, the crust is thicker beneath basement highs and thinner beneath basins, implying... |
| Tipo: Text |
Palavras-chave: Seismic refraction; Oceanic crust; Mohns Ridge; Mantle. |
| Ano: 2000 |
URL: https://archimer.ifremer.fr/doc/2000/publication-681.pdf |
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| Ruffine, Livio; Geli, Louis. |
| Summary of Marsitecruise The scientific cruise MARSITECRUISE of R/V Pourquoi pas? Took place from 28 October to 17 November 2014. Part of the operations were carried out within the frame of the MARSITE programme supported by the European Union, which aims at better understanding the behaviour of the North Anatolian fault in the Marmara sea in view of improving the assessment of the seismic hazard weighing on the Istanbul region. Coordinated by the Observatory of the University of Kandilli (KOERI, based in Istanbul), MARSITE groups 23 partners and includes different components: land, spatial and marine. The marine operations of the programme were coordinated by Ifremer and conducted using Italian (R/V Urania) and French (R/V Pourquoi pas?) naval means.... |
| Tipo: Text |
Palavras-chave: Sea of Marmara; Geochemistry; Seismicity. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00453/56480/58177.pdf |
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| Grall, Celine; Henry, P.; Thomas, Yannick; Westbrook, Graham; Cagatay, M. N.; Marsset, Bruno; Saritas, H.; Cifci, G.; Geli, Louis. |
| [1] High-resolution 3-D seismic data acquired in the Sea of Marmara on the Western High, along the northwestern branch of the North Anatolian Fault (also known as the Main Marmara Fault), shed new light on the evolution of the deformation over the last 500–600 ka. Sedimentary sequences in ponded basins are correlated with glacioeustatic cycles and transitions between marine and low sea/lake environments in the Sea of Marmara. In the 3 × 11 km2 of the 3-D seismic survey, deformation over the last 405–490 ka is localized along the main fault branch and north of it, where N130°–N140° trending normal faults and N40°–N50° folding accommodated strike-slip deformation associated with active argillokinesis. There is some evidence that deformation was more... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00169/28074/26289.pdf |
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| Nouze, Herve; Cosquer, Emmanuel; Collot, Julien; Foucher, Jean-paul; Klingelhoefer, Frauke; Lafoy, Yves; Geli, Louis. |
| High-resolution reflection and refraction seismic data were collected in 2004 to investigate, in further detail than allowed by pre-existing low resolution seismic data, the nature of a Bottom Simulating Reflector (BSR) that extends over a broad area of the Fairway Basin, a rifted, continental structure located on the eastern flank of the Lord Howe Rise, to the southwest of New Caledonia. Two main reflectors are documented: the shallower (RN) mimics the seafloor and has a negative polarity while the deeper (RP) does not always mimic the seafloor and has a positive polarity. Using the existing regional seismic lines, we can show that reflector RN can be continuously followed up to DSDP 208 drill hole site. Reflector RP is discontinuous and cannot be traced... |
| Tipo: Text |
Palavras-chave: Stratigraphy; Gas hydrates; Geophysics; Southwest Pacific; Fairway Basin; BSR. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7321.pdf |
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| Bernard, Pascal; Feron, Romain; Plantier, Guy; Nercessian, Alexandre; Couteau, Julien; Sourice, Anthony; Feuilloy, Mathieu; Cattoen, Michel; Seat, Han‐cheng; Chawah, Patrick; Chéry, Jean; Brunet, Christophe; Boudin, Frédérick; Boyer, Daniel; Gaffet, Stéphane; Geli, Louis; Pelleau, Pascal. |
| We report here the design, performance, and in situ demonstration, on‐land and offshore, of an innovative high‐resolution low‐cost optical (laser) seismometer. The instrument was developed within the Laser Interferometry for Earth Strain project (French Agence Nationale de la Recherche [ANR] program), and first tested at the low‐noise underground laboratory Laboratoire Souterrain à Bas Bruit (LSBB, France). It is based on Fabry–Pérot optical interferometry between the extremity of a probing optical fiber and a reflecting mirror secured to the mobile mass of a passive 2 Hz geophone. The detection technique is based on the wavelength modulation of the laser diode (1310 nm), which allows the separation of the optical power into two signals in quadrature,... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00585/69743/70207.pdf |
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| Dupre, Stephanie; Scalabrin, Carla; Grall, Celine; Augustin, Jean-marie; Henry, Pierre; Sengor, A. M. Celal; Goeruer, Naci; Cagatay, M. Namik; Geli, Louis. |
| Understanding of the evolution of fluid-fault interactions during earthquake cycles is a challenge that acoustic gas emission studies can contribute. A survey of the Sea of Marmara using a shipborne, multibeam echo sounder, with water column records, provided an accurate spatial distribution of offshore seeps. Gas emissions are spatially controlled by a combination of factors, including fault and fracture networks in connection to the Main Marmara Fault system and inherited faults, the nature and thickness of sediments (e.g., occurrence of impermeable or gas-bearing sediments and landslides), and the connectivity between the seafloor and gas sources, particularly in relation to the Eocene Thrace Basin. The relationship between seepage and fault activity is... |
| Tipo: Text |
Palavras-chave: Fluid emissions; Gas; Water column acoustics; Multibeam echo sounder; Sea of Marmara; Tectonics. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00268/37972/36049.pdf |
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| Henry, P.; Grall, Celine; Kende, J.; Viseur, S.; Ozeren, M. S.; Sengor, A. M. C.; Dupre, Stephanie; Scalabrin, Carla; Geli, Louis. |
| The Sea of Marmara is traversed by the North Anatolian Fault system and also presents abundant emission sites of methane gas into the water column. In order to assess the spatial relationship between gas emissions and active faults, the distribution of distances between gas emission sites and the nearest fault is calculated and compared with the distribution of distances between a uniform random distribution of points (Poisson process representing the null hypothesis of an absence of relationship between gas emissions and faults) and the nearest fault. Interestingly, the distance distribution for the Poisson process is nearly exponential, indicating that the fault map does not have a characteristic scale other than that representing the intensity of the... |
| Tipo: Text |
Palavras-chave: Cold seeps; Gas emissions; Transform plate boundary; Strike-slip fault; Damage zone. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00441/55252/56739.pdf |
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| Klingelhoefer, Frauke; Lafoy, Y; Collot, Julien; Cosquer, Emmanuel; Geli, Louis; Nouze, Herve; Vially, R. |
| [1] During the Zoneco 11 marine geophysical survey (September 2004), two deep reflection seismic profiles recorded by ocean bottom seismometers were acquired in the offshore domain west of New Caledonia. The northern profile crosses the New Caledonia Basin, the Fairway Ridge, the Fairway Basin, and the Lord Howe Rise. The southern profile crosses the Norfolk Rise south of New Caledonia, the New Caledonia Basin, the Fairway Ridge and Basin, and ends at the foot of Lord Howe Rise. On the northern profile the Lord Howe Rise has a crustal thickness of 23 km and exhibits seismic velocities and velocity gradients characteristic of continental crust. The crust thins to 12-15 km in the neighboring Fairway Basin, which is interpreted to be of thinned continental... |
| Tipo: Text |
Palavras-chave: Crustal structure; SW Pacific; Wide angle seismic. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3543.pdf |
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| Henry, Pierre; Tryon, Mike; Bourlange, Sylvain; Geli, Louis; Zitter, Tiphaine; Bouloubassi, Ioanna; Burnard, Pete; Cagatay, M Namik; Chevalier, Nicolas; Gasperini, Luca; Gorur, Naci; Gerigk, Christoph; Leveque, Claude; Le Pichon, Xavier; Lopez-garcia, Purification; Massol, Alain; Mercier De Lepinay, Bernard; Natalin, Boris; Ozeren, Sinan; Pierre, Catherine; Ritt, Benedicte; Sengor, Am Celal; Ucarkus, Gulsen. |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00398/50962/51714.pdf |
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| Ruffine, Livio; Germain, Yoan; Polonia, Alina; De Prunele, Alexis; Croguennec, Claire; Donval, Jean-pierre; Pitel-roudaut, Mathilde; Ponzevera, Emmanuel; Caprais, Jean-claude; Brandily, Christophe; Grall, Celine; Bollinger, Claire; Geli, Louis; Gasperini, Luca. |
| Within the Sea of Marmara, the highly active North Anatolian Fault (NAF) is responsible for major earthquakes (Mw>=7), and acts as a pathway for fluid migration from deep sources to the seafloor. This work reports on pore water geochemistry from three sediment cores collected in the Gulfs of Izmit and Gemlik, along the Northern and the Middle strands of the NAF, respectively. The resulting data set shows that anaerobic oxidation of methane (AOM) is the major process responsible for sulfate depletion in the shallow sediment. In the Gulf of Gemlik, depth concentration profiles of both sulfate and alkalinity exhibit a kink-type profile. The Sulfate Methane Transition Zone (SMTZ) is located at moderate depth in the area. In the Gulf of Izmit, the low... |
| Tipo: Text |
Palavras-chave: Anaerobic oxidation of methane; North Anatolian Fault; Pore water geochemistry; Sea of Marmara; Seismic activity. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00272/38339/36570.pdf |
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| Geli, Louis; Cochran, James R.; Lee, T. C.; Francheteau, J.; Labails, C.; Fouchet, C.; Christie, D.. |
| The flanks of the Southeast Indian Ridge are characterized by anomalously low subsidence rates for the 0-25 Ma period: less than 300 m Ma(-1/2) between 101 degrees E and 120 degrees E and less than 260 m Ma(-1/2) within the Australian-Antarctic Discordance (AAD), between 120 degrees E and 128 degrees E. The expected along-axis variation in mantle temperature (similar to 50 degrees C) is too small to explain this observation, even when the temperature dependence of the mantle physical properties is accounted for. We successively analyze the effect on subsidence of different factors, such as variations in crustal thickness; the dynamic contribution of an old, detached slab supposedly present within the mantle below the AAD; and depletion in phi(m), a... |
| Tipo: Text |
Palavras-chave: Southeast Indian Ridge; Seafloor subsidence; Mantle temperature. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00068/17898/15449.pdf |
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| Ruffine, Livio; Donval, Jean-pierre; Croguennec, Claire; Burnard, Pete; Lu, Hailong; Germain, Yoan; Legoix, Ludovic N.; Bignon, Laurent; Cagatay, M. Namik; Marty, Bernard; Madre, David; Pitel-roudaut, Mathilde; Henry, Pierre; Geli, Louis. |
| On continental margins, upward migration of fluids from various sources and various subsurface accumulations, through the sedimentary column to the seafloor, leads to the development of cold seeps where chemical compounds are discharged into the water column. MarsiteCruise was undertaken in November 2014 to investigate the dynamics of cold seeps characterized by vigorous gas emissions in the Sea of Marmara (SoM). A previous paper published by Bourry et al. (2009) presented the gas geochemistry of three seeps sampled along three different segments in the SoM. Their findings showed that the seeps were sourced by three different reservoirs. In this paper, seventeen seeps were investigated to determine the gas sources, unravel reservoir contributions, and... |
| Tipo: Text |
Palavras-chave: Abiotic CO2-source; Gas bubbles; Molecular and isotopic compositions; Primary and secondary methanogenesis; Sea of Marmara; Seeps; Thermogenic gases. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00411/52203/52926.pdf |
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| Ondreas, Helene; Aslanian, Daniel; Geli, Louis; Olivet, Jean-louis; Briais, Anne. |
| The spreading rate at the Pacific-Antarctic Ridge (PAR) increases rapidly from 54 mm/yr near Pitman Fracture Zone (FZ) up to 76 mm/yr near Udintsev FZ, resulting in three domains of axial morphology: an axial valley south of Pitman FZ, an axial high north of Saint Exupery FZ, and in between, the transitional domain extends over 650 km. It comprises sections of ridge with an axial valley or an axial high and generally displays a very low cross-sectional relief. It is also characterized by two propagating rifts. Two domains of different seafloor roughness appear south of Udintsev FZ: east of 157 degreesW these two domains are separated by a 1000-km V-shaped boundary. West of 157 degreesW, the boundary approximately coincides with Chron 3a or Chron 4. The... |
| Tipo: Text |
Palavras-chave: Spreading; Segmentation; Geomorphology; Seafloor; Ridge. |
| Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/2001/publication-438.pdf |
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| Klingelhoefer, Frauke; Labails, Cinthia; Cosquer, Emmanuel; Rouzo, Stephane; Geli, Louis; Aslanian, Daniel; Olivet, Jean-louis; Sahabi, M.; Nouze, Herve; Unternehr, P.. |
| A total 1500 km of seismic reflection and wide-angle profiles were acquired off the southern Moroccan margin during the DAKHLA cruise, a joint project of Ifremer, the Universities of Brest, El Jadida and Lisbon and Total. The shots along two profiles parallel to the margin and two profiles perpendicular to the margin were also recorded by ocean bottom seismometers (OBS). The profiles perpendicular to the margin were additionally extended on land using 14 stations on the northern profile and 11 stations on the southern profile. Modelling of the reflection and wide-angle seismic data reveals a 10 km deep sedimentary basin including two high velocity carbonate layers. Lateral crustal thinning is observed from a 27 km thick crystalline continental crust to a 7... |
| Tipo: Text |
Palavras-chave: Ocean continent transition; Keyword wide angle seismic; Southern Moroccan margin. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6410.pdf |
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| Registros recuperados: 56 | |
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