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| Registros recuperados: 18 | |
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| Menesguen, Claire; Hua, Bach-lien; Carton, Xavier; Klingelhoefer, Frauke; Schnurle, Philippe; Reichert, C.. |
| The North Atlantic temperature and salinity distributions are strongly influenced by the existence of Mediterranean eddies (meddies) which significantly contribute to the transport of the warm and salty Mediterranean Water along different pathways. The most common pathways are observed to be North and West of the Canary Current. However, a 2011 seismic reflection cruise conducted by BGR and Ifremer near the North-Western African margin of Morocco, MIRROR Leg 2, revealed the presence of a meddy south of the Azores front and very close to the Morocco coastline. This unusual location of a strong Mediterranean Water anomaly is confirmed by other data. Moreover, meddies are long-lived structures whose dynamics and dissipation are not yet completely understood.... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00074/18499/16046.pdf |
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| Tsang-hin-sun, Eve; Evain, Mikael; Julia, J; Lamarque, G; Schnurle, Philippe. |
| This study investigates the seismic structure and anisotropy in the crust beneath Madagascar and south-eastern Africa, using receiver functions. The understanding of seismic anisotropy is essential for imaging past and present deformation in the lithosphere-asthenosphere system. In the upper mantle, seismic anisotropy mainly results from the orientation of olivine, which deforms under tectonic (fossil anisotropy) or flow processes (in the asthenosphere). In the crust, the crystallographic alignment of amphiboles, feldspars(plagioclase) or micas or the alignment of heterogeneities such as fractures, add to a complex geometry, which results in challenges to understanding the Earth's shallow structure. The decomposition of receiver functions into back-azimuth... |
| Tipo: Text |
Palavras-chave: Crustal seismic anisotropy; Inherited structural heterogeneities; Crustal stress; Receiver function harmonics; Madagascar; Africa; EARS. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00686/79843/82668.pdf |
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| Evain, Mikael; Schnurle, Philippe; Lepretre, Angelique; Verrier, Fanny; Watremez, Louise; Thompson, Joseph Offei; De Clarens, Philippe; Aslanian, Daniel; Moulin, Maryline. |
| Deep seismic acquisitions and a new kinematic study recently highlighted the presence of continental crust in both the southern Mozambique's Coastal Plain (MCP) and further offshore in the North Natal Valley (NNV). Such findings falsify previous geodynamic scenarios based on the kinematic overlap between Antarctica and Africa plates, thus profoundly impacting our understanding East-Gondwana break-up. Using an updated position of Antarctica with respect to Africa this study reconsider the formation mechanism of East-African margins and most specifically of the Limpopo margin (LM). Coincident wide-angle and multi-channel seismic data acquired within the PAMELA project are processed to image the sedimentary and deep crustal structure along a profile that runs... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00678/79004/81397.pdf |
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| Moulin, Maryline; Klingelhoefer, Frauke; Afilhado, Alexandra; Aslanian, Daniel; Schnurle, Philippe; Nouze, Herve; Rabineau, Marina; Beslier, Marie-odile; Feld, Aurelie. |
| The conjugate margins system of the Gulf of Lion and West Sardinia (GLWS) represents a unique natural laboratory for addressing fundamental questions about rifting due to its landlocked situation, its youth, its thick sedimentary layers, including prominent palaeo-marker such as the MSC event, and the amount of available data and multidisciplinary studies. The main goals of the SARDINIA experiment, were to (i) investigate the deep structure of the entire system within the two conjugate margins: the Gulf of Lion and West Sardinia, (ii) characterize the nature of the crust, and (iii) define the geometry of the basin and provide important constrains on its genesis. This paper presents the results of P-wave velocity modelling on three coincident near-vertical... |
| Tipo: Text |
Palavras-chave: Marge continentale passive; Structure crustale; Réfraction; Golfe du Lion; Croûte océanique; Domaine transitionnel; Continental passive margin; Crustal structure; Wide-angle seismic; Gulf of Lion; Oceanic crust; Transitional domain. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00283/39422/38269.pdf |
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| Biari, Youssef; Klingelhoefer, Frauke; Sahabi, Mohamed; Aslanian, Daniel; Schnurle, Philippe; Berglar, K.; Moulin, Maryline; Mehdi, K.; Graindorge, D.; Evain, Mikael; Benabdellouahed, Massinissa; Reichert, C.. |
| The structure of the Moroccan and Nova Scotia conjugate rifted margins is of key importance for understanding the Mesozoic break-up and evolution of the northern central Atlantic Ocean basin. Seven combined multichannel reflection (MCS) and wide-angle seismic (OBS) data profiles were acquired along the Atlantic Moroccan margin between the latitudes of 31.5° and 33° N during the MIRROR seismic survey in 2011, in order to image the transition from continental to oceanic crust, to study the variation in crustal structure and to characterize the crust under the West African Coast Magnetic Anomaly (WACMA). The data were modeled using a forward modeling approach. The final models image crustal thinning from 36 km thickness below the continent to approximately 8... |
| Tipo: Text |
Palavras-chave: Moroccan continental margin; Wide-angle seismic modeling; Deep crustal structure; Ocean continent transition. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00273/38401/36726.pdf |
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| Aidi, Chafik; Beslier, Marie-odile; Yelles-chaouche, Abdel Karim; Klingelhoefer, Frauke; Bracene, Rabah; Galve, Audrey; Bounif, Abdallah; Schenini, Laure; Hamai, Lamine; Schnurle, Philippe; Djellit, Hamou; Sage, Francoise; Charvis, Philippe; Deverchere, Jacques. |
| During the Algerian-French SPIRAL survey aimed at investigating the deep structure of the Algerian margin and basin, two coincident wide-angle and reflection seismic profiles were acquired in central Algeria, offshore Greater Kabylia, together with gravimetric, bathymetric and magnetic data. This ~260 km-long offshore-onshore profile spans the Balearic basin, the central Algerian margin and the Greater Kabylia block up to the southward limit of the internal zones onshore. Results are obtained from modeling and interpretation of the combined data sets. The Algerian basin offshore Greater Kabylia is floored by a thin oceanic crust (~4 km) with P-wave velocities ranging between 5.2 and 6.8 km/s. In the northern Hannibal High region, the atypical 3-layer... |
| Tipo: Text |
Palavras-chave: Mediterranean Sea; Algerian margin; Crustal structure; Tectonic inversion; Post-accretion magmatism; Deep seismics. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00425/53677/54519.pdf |
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| Evain, Mikael; Afilhado, A.; Rigoti, C.; Loureiro, Afonso; Alves, D.; Klingelhoefer, Frauke; Schnurle, Philippe; Feld, Aurelie; Fuck, R.; Soares, J.; De Lima, M. Vinicius; Corela, C.; Matias, L.; Benabdellouahed, Massinissa; Baltzer, Agnes; Rabineau, Marina; Viana, A.; Moulin, Maryline; Aslanian, Daniel. |
| The structure and nature of the crust underlying the Santos Basin-São Paulo Plateau System (SSPS), in the SE Brazilian margin, are discussed based on five wide-angle seismic profiles acquired during the Santos Basin (SanBa) experiment in 2011. Velocity models allow us to precisely divide the SSPS in six domains from unthinned continental crust (Domain CC) to normal oceanic crust (Domain OC). A seventh domain (Domain D), a triangular shape region in the SE of the SSPS, is discussed by Klingelhoefer et al. (2014). Beneath the continental shelf, a ~100 km wide necking zone (Domain N) is imaged where the continental crust thins abruptly from ~40 km to less than 15 km. Toward the ocean, most of the SSPS (Domains A and C) shows velocity ranges, velocity... |
| Tipo: Text |
Palavras-chave: Santos Basin; SAo Paulo Plateau; Crustal structure; Wide-angle seismic. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00276/38715/37232.pdf |
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| Moulin, Maryline; Aslanian, Daniel; Evain, Mikael; Leprêtre, Angelique; Schnurle, Philippe; Verrier, Fanny; Thompson, Joseph Offei; De Clarens, P.; Leroy, S.; Dias, N.; The Pamela‐moz35 Team,. |
| The Natal Valley, offshore Mozambique, is a key area for understanding the evolution of East Gondwana. Within the scope of the integrated multidisciplinary PAMELA project, we present new wide‐angle seismic data and interpretations, which considerably alter Geoscience paradigms. These data reveal the presence of a 30 km‐thick crust that we argue to be of continental nature. This falsifies all the most recent paleo‐reconstructions of the Gondwana. This 30 km‐thick continental crust 1000 m below sea level implies a complex history with probable intrusions of mantle‐derived melts in the lower crust, connected to several occurrences of magmatism, which seems to evidence the crucial role of the lower continental crust in passive margin genesis. |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00598/71055/69368.pdf |
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| Loureiro, Afonso; Schnurle, Philippe; Klingelhofer, F.; Afilhado, A.; Pinheiro, Joao Marcelo; Evain, Mikael; Gallais, Flora; Dias, N. A.; Rabineau, Marina; Baltzer, Agnes; Benabdellouahed, Massinissa; Soares, J.; Fuck, R.; Cupertino, J. A.; Viana, A.; Matias, L.; Moulin, Maryline; Aslanian, Daniel; Vinicius Aparecido Gomes De Lima, M.. |
| Twelve combined wide-angle refraction and coincident multi-channel seismic profiles were acquired in the Jequitinhonha-Camamu-Almada, Jacuípe, and Sergipe-Alagoas basins, NE Brazil, during the SALSA experiment in 2014. Profiles SL11 and SL12 image the Jequitinhonha basin, perpendicularly to the coast, with 15 and 11 four-channel ocean-bottom seismometers, respectively. Profile SL10 runs parallel to the coast, crossing profiles SL11 and SL12, imaging the proximal Jequitinhonha and Almada basins with 17 ocean-bottom seismometers. Forward modelling, combined with pre-stack depth migration to increase the horizontal resolution of the velocity models, indicates that sediment thickness varies between 3.3 km and 6.2 km in the distal basin. Crustal thickness at... |
| Tipo: Text |
Palavras-chave: NE Brazil; South Atlantic Ocean; Passive margins; Wide-angle refraction seismic; PSDM; Crustal structure; Cretaceous breakup; Lower continental crust. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00428/53928/55054.pdf |
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| Klingelhoefer, Frauke; Evain, Mikael; Afilhado, A.; Rigoti, Caesar; Loureiro, Afonso; Alves, D.; Lepretre, Angelique; Moulin, Maryline; Schnurle, Philippe; Benabdellouahed, Massinissa; Baltzer, Agnes; Rabineau, Marina; Feld, Aurelie; Viana, A.; Aslanian, Daniel. |
| During the Sanba (Santos basin seismic transect) experiment in 2010–2011, a 380-km-long combined wide-angle and reflection seismic profile has been acquired using 30 ocean-bottom seismometers, a 4.5 km seismic streamer and a 8900 in.3 airgun array. The Sanba 3 profile crosses the southern flank of the Sao Paulo Plateau, the Sao Paulo Ridge and the easternmost Santos Basin in an east–west direction. Its eastern end is located on undisturbed oceanic crust. Tomographic and forward modelling of the wide-angle seismic data reveals that the sedimentary thickness is variable with only 1–2 km on top of the ridge and thickening to 4–5 km in the basin. Crustal thickness at the ridge is about 18 km and the relative layer thickness and velocity gradients indicate a... |
| Tipo: Text |
Palavras-chave: Controlled source seismology; Seismic tomography; Mid-ocean ridge processes; Continental margins: divergent; Continental tectonics: extensional; Crustal structure; South America. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00242/35296/33826.pdf |
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| Pinheiro, Joao Marcelo; Schnurle, Philippe; Evain, Mikael; Afilhado, A.; Gallais, Flora; Klingelhoefer, Frauke; Loureiro, Afonso; Fuck, R.; Soares, J.; Cupertino, J. A.; Viana, A.; Rabineau, Marina; Baltzer, Agnes; Benabdellouahed, Massinissa; Dias, N.; Moulin, Maryline; Aslanian, Daniel; Morvan, Laetitia; Maze, Jean-pierre; Pierre, Delphine; Pitel-roudaut, Mathilde; Rio, I; Alves, D.; Barros Junior, P.; Biari, Youssef; Corela, C.; Crozon, Jacques; Duarte, J. L.; Ducatel, Cecile; Falcao, C.; Fernagu, Philippe; Le Piver, David; Mokeddem, Zohra; Pelleau, Pascal; Rigoti, C.; Roest, Walter; Roudaut, Mickael. |
| The structure and nature of the crust underlying the Camamu-Almada-Jequitinhonha-Sergipe-Alagoas basins System, in the NE Brazilian margin, were investigated based on the interpretation of 12 wide-angle seismic profiles acquired during the SALSA (Sergipe ALagoas Seismic Acquisition) experiment in 2014. In this work, we present two 220-km-long NW-SE combined wide-angle and reflection seismic profiles, SL 01 and SL 02, that have been acquired using 15 ocean-bottom-seismometers along each profile, offshore the southern part of the Sergipe Alagoas Basin (SAB), north of the Vaza-Barris Transfer zone. The SL 02 has a 150-km long inland continuation with 20 land-seismic-stations until the Sergipano Fold Belt (SFB). Wide-angle seismic forward modeling allows us to... |
| Tipo: Text |
Palavras-chave: South Atlantic ocean; NE Brazil; Sergipe-Alagoas basin; Passive margins; Wide-angle refraction seismics; Crustal structure; Tectonic inheritance. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00461/57263/59315.pdf |
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| Lepretre, Angelique; Klingelhoefer, Frauke; Graindorge, David; Schnurle, Philippe; Beslier, M. O.; Yelles, K.; Deverchere, Jacques; Bracene, R.. |
| The origin of the Algerian margin remains one of the key questions still discussed in the Western Mediterranean sea, due to the imprecise nature and kinematics of the associated basin during the Neogene. For the first time, the deep structure of the Maghrebian margin was explored during the SPIRAL seismic survey. In this work, we present a N-S transect off Tipaza (west of Algiers), a place where the margin broadens due to a topographic high (Khayr-al-Din Bank). New deep penetration seismic profiles allow us to image the sedimentary sequence in the Algerian basin and the crustal structure at the continent-ocean boundary. Modeling of the wide-angle data shows thinning of the basement, from more than 15km in the continental upper margin to only 5–6km of... |
| Tipo: Text |
Palavras-chave: Algerian margin; Crustal structure; Wide-angle seismic data; Multiphased tectonic evolution; Western Mediterranean back-arc basins; Contractional reactivation. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00152/26333/24412.pdf |
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| Schnurle, Philippe; Liu, Char-shine. |
| We have implemented a 2-dimensional numerical model for simulating gas hydrate and free gas accumulation in marine sediments. The starting equations are those of the conservation of the transport of momentum, energy, and mass, as well as those of the thermodynamics of methane hydrate stability and methane solubility in the pore-fluid. These constitutive equations are then integrated into a finite element in space, finite-difference in time scheme. We are then able to examine the formation and distribution of methane hydrate and free gas in a simple geologic framework, with respect to the geothermal heat flow, fluid flow, the methane in-situ production and basal flux. Three simulations are performed, leading to the build up of hydrate emplacements largely... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00056/16755/14269.pdf |
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| Mihoubi, A.; Schnurle, Philippe; Benaissa, Z.; Badsi, M.; Bracene, R.; Djelit, H.; Geli, Louis; Sage, F.; Agoudjil, A.; Klingelhoefer, Frauke. |
| This study presents the results of a deep seismic survey across the north Algerian margin, based on the combination of 2-D multichannel and wide-angle seismic data simultaneously recorded by 41 ocean bottom seismometers deployed along a north-south line extending 180 km off Jijel into the Algerian offshore basin, and 25 land stations deployed along a 100-km-long line, cutting through the Lesser Kabylia and the Tellian thrust-belt. The final model obtained using forward modelling of the wide-angle data and pre-stack depth migration of the seismic reflection data provides an unprecedented view of the sedimentary and crustal structure of the margin. The sedimentary layers in the Algerian basin are 3.75 km thick to the north and up to 4.5-5 km thick at the... |
| Tipo: Text |
Palavras-chave: Tomography; Continental margins: divergent; Africa. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00217/32836/32150.pdf |
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| Schnurle, Philippe; Liu, Char-shine; Lin, Andrew T.; Lin, Saulwood. |
| A dense seismic reflection survey with up to 250-m line-spacing has been conducted in a 15 × 15 km wide area offshore southwestern Taiwan where Bottom Simulating Reflector is highly concentrated and geochemical signals for the presence of gas hydrate are strong. A complex interplay between north–south trending thrust faults and northwest–southeast oblique ramps exists in this region, leading to the formation of 3 plunging anticlines arranged in a relay pattern. Landward in the slope basin, a north–south trending diapiric fold, accompanied by bright reflections and numerous diffractions on the seismic profiles, extends across the entire survey area. This fold is bounded to the west by a minor east-verging back-thrust and assumes a symmetric shape, except at... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00056/16754/14248.pdf |
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| Aslanian, Daniel; Moulin, Maryline; Schnurle, Philippe; Klingelhoefer, Fraucke; Leroux, Estelle; Rabineau, Marina; Gailler, Audrey; Bache, Francois; Gorini, Christian; Kuroda, J.; Eguchi, N.; Droxler, Andre W.; Alain, Karine; Roure, François; Haq, B.. |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00149/26055/24160.pdf |
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| Registros recuperados: 18 | |
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