Consulta: creatorFacets:"Sibuet, Jean-claude"
Registros recuperados: 64
Data/hora: 01/06/2024 13:53:58

The ocean-continent transition in the uniform lithospheric stretching model : role of partial melting in the mantle
Provedor de dados: 5
Autores: Foucher, Jean-paul; Le Pichon, Xavier; Sibuet, Jean-claude.
The role of partial melting in the uniform lithospheric stretching model of continental margin formation is explored.  It is shown that the transition from continental lithosphere stretching to oceanic accretion is most probably controlled by the production of a significant amount of partial melting in the asthenosphere immediately below the lithosphere, which requires stretching factors larger than 3.  It is also shown that, at stretching factors exceeding 2, the law of subsidence is significantly changed by the presence of partial melt in the underlying asthenosphere.  The implications for the existence of deep continental margin basins on thinned continental crusts are examined. The Armorican deep continental margin basin is taken as an example. [NOT...
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1981
URL: http://archimer.ifremer.fr/doc/1981/publication-5375.pdf

PostSeafloor Spreading Volcanism in the Central East South China Sea and its Formation Through an Extremely Thin Oceanic Crust
Provedor de dados: 5
Autores: Zhao, Minghui; He, Enyuan; Sibuet, Jean-claude; Sun, Longtao; Qiu, Xuelin; Tan, Pingchuan; Wang, Jian.
P-wave velocity models were obtained by forward and inverse modeling from 38 ocean bottom seismometers deployed in the central East sub-basin of the South China Sea (SCS). Four types of crust have been defined; a) thin oceanic crust (&lt;5 km), b) typical oceanic crust (5-6 km), c) thick oceanic crust hosting post-spreading volcanoes (&gt;6 km) with significant intrusive roots, and d) thick oceanic crust with enhanced spreading features (&gt;6 km) but without significant roots. Within the central East sub-basin, the thin oceanic crust, only identified inside a 80-km wide zone, is located within an overall 150-km wide domain characterized by N055° seafloor spreading trends. The post-spreading volcanoes were formed during a N-S tensional episode around 6-10...
Tipo: Text
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00427/53882/54951.pdf

Geophysical data collected underway on glomar challenger, leg 47B
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Ryan, William B.f.; Gustafson, Ted B.; Smith, S.m.
The scientific party aboard Glomar Challenger collected geophysical data during DSDP Leg 47B, which commenced from Vigo, Spain, and terminated at Brest, France (Figure 1). Site 398 (40°57.6'N, 10°43.1'W), located just south of Vigo Seamount and about 95 miles West of Porto, Portugal, was drilled from 13 April 1976 to 9 May 1976. Table 1 gives satellite positions, distance (in nautical miles along the track) and the speed and course between successive navigation points. The positioning error along the trackline is approximately 1 nautical mile. Distances are shown (Figure 1) along the trackline every 50 nautical miles and annotated every 100 nautical miles. Time is marked by crosses every 2 hours and annotated every 4 hours. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1979
URL: http://archimer.ifremer.fr/doc/1979/publication-5241.pdf

Origin of the southern Okinawa Trough volcanism from detailed seismic tomography - art. no. B08308
Provedor de dados: 5
Autores: Lin, Jing-yi; Sibuet, Jean-claude; Lee, Chao-shing; Hsu, Shu-kun; Klingelhoefer, Frauke.
Magmatism associated with subducting plate edges or slab tears has been suggested in the southern Okinawa Trough. The cross back-arc volcanic trail, which consists of a cluster of about 70 seamounts, is located above a Ryukyu slab tear lying along the 123.3°E meridian. In November 2003, more than 3300 earthquakes recorded in this area by 15 ocean bottom seismometers and surrounding land stations during a period of 12 days were used to determine the three-dimensional Vp and Vs velocity structures and Vp/Vs ratios. A mantle inflow characterized by low Vp and Vs and high Vp/Vs passing through the slab tear is imaged. The fluid and/or melt component is rising obliquely from the slab tear in the directions of the cross back-arc volcanic trail, the northern...
Tipo: Text
Palavras-chave: Slab component volcanism; Vp/Vs tomography; Southern Okinawa Trough back arc basin.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3032.pdf

Rifting consequences of three plate separation
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Srivastava, Shiri.
Submarine sedimentary basins parallel to the trends of passive continental margins are well explained by tensional processes between two lithospheric plates. This leaves open the enigma of many basins which strike across margins. We use examples from the North Atlantic to show that such basins may be formed during the initial rifting stage due to enhanced lithospheric thinning caused by the separation of three plates. We suggest that volcanics can be emplaced in these basins and, in the extreme case, where mantle temperature and consequently the degree of partial melting are particularly high, that basaltic flows can be thick enough to fill and hide the basins.
Tipo: Text
Ano: 1994
URL: http://archimer.ifremer.fr/doc/00196/30732/30291.pdf

From intracratonic extension to mature spreading in back arc basins: Examples from the Okinawa, Lau, North Fiji basins
Provedor de dados: 5
Autores: Auzende, Jean-marie; Boespflug, Xavier; Bougault, Henri; Dosso, Laure; Foucher, Jean-paul; Joron, Jean-louis; Ruellan, Etienne; Sibuet, Jean-claude.
Three cruises (POP 1, SEAPSO 3 and SEAPSO 4) carried out during the "Tour du Monde" of the R.V. Jean Charcot allow us to obtain new structural and geochemical data for the Okinawa, North Fiji and Lau basins. Taken together, the structural and geochemical data illustrate a difference in evolution stages of these sites. The less evolved stage is represented by the Okinawa basin, where accretion is evidenced only by volcanic intrusion into a thinned continental crust. The most evolved stage is illustrated in the North Fiji basin, where the present-day accretion can be directly compm·ed to the East Pacific Ridge. The Lau basin displays an intem1ediate stage with a complex system of accretionary ridges. This difference in the evolution stage is translated in...
Tipo: Text
Palavras-chave: Ouest Pacifique; Bassins arriere arc; Structure; Accretion; Geochimie; West Pacific; Back arc basins; Structure; Accretion; Geochemistry.
Ano: 1990
URL: http://archimer.ifremer.fr/doc/00119/23058/20893.pdf

Thermal regime of the northern bay of biscay continental margin in the vicinity of DSDP sites 400 to 402
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Foucher, Jean-paul.
Ten conventional oceanic surface heat flow measurements were made over the northern margin of the Bay of Biscay in the vicinity of the DSDP Sites 400 to 402 during the R/V Suroit - SU 01 (December 1975) and R/v Jean Charcot - CH 66 (February 1976) cruises of CNEXO. These measurements, complemented by the heat flow determination made at Site 402 during Leg 48 of the Deep Sea Drilling Project (Erickson et al; this volume) provide information on the thermal regime of the margin.The main observation is that the regional heat flux over the margin is substantially lower than over the adjacent Western European continental area.We suggest in this report that the observed heat flux contrast provides constraints on the debatable nature of the crustal thinning...
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1979
URL: http://archimer.ifremer.fr/doc/1979/publication-5279.pdf

Bay of biscay and Pyrenees
Provedor de dados: 5
Autores: Choukroune, Pierre; Le Pichon, Xavier; Seguret, Michel; Sibuet, Jean-claude.
The different hypotheses proposed for the creation of the Bay of Biscay are reviewed. New geological and geophysical data collected in the last two years in the Bay and in the Pyrenean domain give new insight into the tectogenesis of the Pyrenees.  Geological data of the Pyrenean area provide tight constraints on the hypothesis of formation of the Bay. The most probable hypothesis is an opening by rotation of the Iberian Peninsula around a pole of rotation situated near Paris, which resulted in strike-slip motion dong the North Pyrenean fault during the Upper Mesozoic.  A progressive westward migration of the pole initiated in the late Cretaceous blocked the motion dong the fault and led to the main Eocene tectogenetic Pyrenean phase. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1973
URL: http://archimer.ifremer.fr/doc/1973/publication-5061.pdf

Western extension of boundary between european and iberian plates during the pyrenean orogeny
Provedor de dados: 5
Autores: Le Pichon, Xavier; Sibuet, Jean-claude.
The kinematics of the Eocene episode of compression between the Iberian and European plates is examined. It is proposed that the boundary between the two plates extended West of the Pyrenees, along the Spanish marginal trench to end West of King's trough at a triple point junction. The pole of relative rotation computed within this hypothesis lies near 5°N ; 62°W and the resulting shortening along the Pyrenees is about 50 km dong 45°E. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1971
URL: http://archimer.ifremer.fr/doc/1971/publication-4918.pdf

Deep sea in situ excess pore pressure and sediment deformation off NW Sumatra and its relation with the December 26, 2004 Great Sumatra-Andaman Earthquake
Provedor de dados: 5
Autores: Sultan, Nabil; Cattaneo, Antonio; Sibuet, Jean-claude; Schneider, Jean-luc.
The swath bathymetric data acquired during the "Sumatra Aftershocks" cruise from the Sunda trench in the Indian Ocean to the north of the Sumatra Island imaged several scars and deposits. In situ pore pressure measurements using the Ifremer piezometer and coring demonstrate that high excess pore pressure and sediment deformation was generated by a recent event in the scar of the slope failure zone identified by J.T. Henstock and co-authors. This excess pore pressure is localized in the upper sedimentary layers and is not related to an interplate subduction process. Numerical simulations of the hydrological system that take into account the hydro-mechanical properties of the upper sediment layer show that the excess pore pressure and sediment deformations...
Tipo: Text
Palavras-chave: Tsunami; Sumatra; Slope failure; Pore pressure; Earthquake.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6740.pdf

Comments on the evolution of the north-east atlantic
Provedor de dados: 5
Autores: Le Pichon, Xavier; Sibuet, Jean-claude.
It has been proposed that the opening of the Bay of Biscay occurred by rotation about a pole situated near Paris (50.0° N, 3.3° E) and not about the pole proposed by Bullard et al.(4) (43.6° N, 1.0° E). The rotation about the first pole results in strike-slip motion aIong the North Pyrenean fault during the pre-Upper-Cretaceous opening, while the rotation about the second pole results in compression there. The second rotation is not compatible with geological data(5) which indicates extension prior to Upper Cretaceous in the Pyrenean region. We wish to show how these two hypothetical rotations agree with the magnetic data of Williams and McKenzie(6). [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1971
URL: http://archimer.ifremer.fr/doc/1971/publication-4898.pdf

La faille nord-pyrénéenne : faille transformante liée à l'ouverture du golfe de gascogne
Provedor de dados: 5
Autores: Sibuet, Jean-claude.
It is demonstrated that the northern Pyrenean fault can be interpreted as a transforming fault related to the opening of the Bay of Biscay. This fault follows a circle centred to the north of Paris, and along which the Iberian Peninsula could have slipped. As a consequence, the Bay of Biscay could have opened without creating any compression in the Pyrenean area.
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1970
URL: http://archimer.ifremer.fr/doc/1970/publication-4883.pdf

Spatial aftershock distribution of the 26 December 2004 great Sumatra-Andaman earthquake in the northern Sumatra area
Provedor de dados: 5
Autores: Lin, Jing-yi; Le Pichon, Xavier; Rangin, Claude; Sibuet, Jean-claude; Maury, Tanguy.
In July 2005, about 6 months after the 2004 great Sumatra-Andaman earthquake, 20 ocean bottom seismometers were deployed in the northern Sumatra area. More than 1000 events were identified during the 12 day recording period. After relocation, the seismicity shows different patterns on each side of the Lower Splay Fault. East of this feature and beneath the Aceh basin and fore arc, the deep earthquakes outline the subduction megathrust fault. West of it, the aftershocks distribution is strongly influenced by the active N-S oceanic fracture zones of the subducted plate. Two N-S trending clusters of 10- to 50-km-deep earthquakes observed below the lower wedge are interpreted as reactivated oceanic fracture zones. The postseismic activity suggests a...
Tipo: Text
Palavras-chave: 2004 great Sumatra Andaman earthquake; Sumatra trench; Andaman trench; Aftershocks; Splay faults; Oblique subduction.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00000/11081/7419.pdf

Problematic plate reconstruction
Provedor de dados: 5
Autores: Tucholke, Brian E.; Sibuet, Jean-claude.
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00095/20617/20618.pdf

56. Morphology and Basement Structures of the Goban Spur Continental Margin (Northeastern Atlantic) and the Role of the Pyrenean Orogeny
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Mathis, B; Pastouret, Léo; Auzende, Jean-marie; Foucher, Jean-paul; Hunter, Peter; Guennoc, P; De Graciansky, Pc; Montadert, L; Masson, Douglas.
Tipo: Text
Ano: 1985
URL: http://archimer.ifremer.fr/doc/00184/29494/27815.pdf

Présentation d'une carte magnétique de l'Atlantique Nord-Est
Provedor de dados: 5
Autores: Guennoc, Pol; Jonquet, Hélène; Sibuet, Jean-claude.
A compilation of magnetic anomalies in the North-East Atlantic based on available aeromagnetic and surface data is presented. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1979
URL: http://archimer.ifremer.fr/doc/1979/publication-5384.pdf

Melting features along the western Ryukyu slab edge (northeast Taiwan): Tomographic evidence - art. no. B12402
Provedor de dados: 5
Autores: Lin, Jing-yi; Hsu, Sk; Sibuet, Jean-claude.
[1] Behind the sedimentary Ryukyu arc lies the Okinawa Trough, whose termination is located at the tip of the Ilan plain ( northern Taiwan), just above the Ryukyu slab edge. The present-day active volcanic front is located 80 - 100 km above the Ryukyu slab and extends from Japan to Kueishantao Island, an islet situated 10 km offshore the Ilan plain. Between December 1990 and May 1999, 3370 earthquakes recorded in northern Taiwan by 65 seismic land stations were used to determine the three-dimensional V-p and V-s velocity structures and V-p/V-s ratios. A low V-s but high V-p/V-s sausage-like body, similar to 30 km in diameter, lies within the Eurasian mantle wedge, on top of the western Ryukyu slab extremity, at depths ranging between 20 and 100 km. We...
Tipo: Text
Palavras-chave: Ryukyu slab; Okinawa Trough; Seismic tomography; Melting features.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00000/10898/7751.pdf

Structure of the Northern Bay of Bengal offshore Bangladesh: Evidences from new multi-channel seismic data
Provedor de dados: 5
Autores: Rangin, Claude; Sibuet, Jean-claude.
New multi-channel seismic data were acquired in the northern part of the Bay of Bengal and at the northernmost termination of the 90°E Indian Ridge offshore Bangladesh. This survey was coupled with a seismic refraction experiment indicating this offshore basin is here floored by a thinned (15 km thick) continental crust, injected by Mesozoic volcanism. This attenuated continental crust is interpreted as formed during Gondwana super-continent fragmentation during a syn-rift period. The dominant tectonic pattern is marked by NE-SW trending tilted blocks filled by syn-rift sediments clearly identified on seismic profiles. The uppermost part of this continental crust (3–4 km thick) shows a complex assemblage of dipping reflectors and west-facing tilted blocks...
Tipo: Text
Palavras-chave: Bay of Bengal; Seismic analysis; Basin structure; Bangladesh.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00378/48974/49381.pdf

New pole for early opening of South Atlantic
Provedor de dados: 5
Autores: Mascle, Jean; Sibuet, Jean-claude.
USING the trends of equatorial, marginal fracture ridges, Le Pichon and Hayes proposed an early phase for the opening of the South Atlantic, with a pole of rotation at 21.5°N, 14°W with respect to Africa. Francheteau and Le Pichon2 tested this plate tectonic model with the whole South Atlantic and assumed that there is a relationship between continental margin offsets, the subsidence of coastal basins, and adjacent marginal fracture zones. We have studied extensions of fracture zones in the Gulf of Guinea and adjacent continental margins and have determined a new early opening pole that differs markedly from the one previously determined. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1974
URL: http://archimer.ifremer.fr/doc/1974/publication-5441.pdf

Intermingled fates of the South China Sea and Philippine Sea plate
Provedor de dados: 5
Autores: Zhao, Minghui; Sibuet, Jean-claude; Wu, Jonny.
Recent studies have shown the extent and nature of the South China Sea (SCS) at the end of spreading by unfolding (i.e. structurally restoring) the Manila slab, which is the subducted part of the SCS, and by identifying the nature of the crust-lithosphere (oceanic or thinned continental) from mid-slab P-wave velocity perturbations (dVp) [1,2]. The objective of this paper is to propose a reconstruction of the SCS at the end of seafloor spreading and to discuss its geodynamic consequences in the context of the SCS and Philippine Sea plate (PSP) evolution. Reasonably accurate PSP paleo-latitudes and poorly defined paleo-declinations were primarily used to establish the kinematic evolution of the PSP through time (e.g. [3,4]) until 2016, when Wu et al. [1]...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00611/72275/71069.pdf

Structure and development of the southeast Newfoundland continental passive margin: derived from SCREECH Transect 3
Provedor de dados: 5
Autores: Deemer, Sharon; Hall, Jeremy; Solvason, Krista; Lau, K. W. Helen; Louden, Keith; Srivastava, Shiri; Sibuet, Jean-claude.
P&gt;New seismic reflection data from the Grand Banks of Newfoundland and the Newfoundland Basin add to the growing knowledge of the composition, structure and history of this non-volcanic margin. Geophysical imaging is now approaching the extent of that done previously on the conjugate margin along Iberia, providing a valuable database for the development of rifting models. Two parallel profiles over the shelf platform image deep crustal fabric representing Precambrian or possibly Appalachian deformation as well as Mesozoic extension. Progressively more intense extension of continental crust is imaged oceanwards without the highly reflective detachments frequently seen on profiles off Galicia. A landward-dipping event 'L' is imaged sporadically and...
Tipo: Text
Palavras-chave: Atlantic Ocean; Submarine tectonics and Volcanism; Continental margins: divergent; Crustal structure.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6919.pdf

Earthquake off Japan could generate strong tsunami arrays
Provedor de dados: 5
Autores: Hsu, Shu-kun; Sibuet, Jean-claude.
The 26 December 2004 earthquake off Sumatra induced a disastrous tsunami that struck in South Asian countries. In a similar context, a potential great earthquake off Japan might occur and generate a strong tsunami in East Asia. The 2004 Sumatra earthquake is the second biggest earthquake (Mw = 9.3) recorded during the last century. It occurred at a depth of 20–30 km, close to an indentation of the Indonesian forearc (Figure l). The rupture propagated about 1200 km northward and terminated north of Andaman Islands.
Tipo: Text
Ano: 2005
URL: http://archimer.ifremer.fr/doc/00451/56258/57827.pdf

Structure of the southernmost Okinawa Trough from reflection and wide-angle seismic data
Provedor de dados: 5
Autores: Klingelhoefer, Frauke; Lee, Chao-shing; Lin, Jing-yi; Sibuet, Jean-claude.
During a passive seismic experiment in the Okinawa Trough the shots of two reflection profiles were recorded by ocean bottom seismometers (OBS). Both profiles include 3 ocean-bottom instruments, are about 65 km in length and located in the axial portion of the southwestern Okinawa Trough. Processing of the reflection seismic data images recent deformation of the sedimentary units. Forward modelling of the wide-angle data on both profiles reveals a 1-2 km thick sedimentary infill overlying an acoustic basement characterised by seismic velocities between 3.2 and 3.5 km/s. Crustal thickness could only be modelled on one profile and was determined to be around 10 km, thickening towards the Ryukyu Arc in the south. Gravity modelling was used to additionally...
Tipo: Text
Palavras-chave: Back arc basin; Crustal structure; Wide angle seismics; Okinawa Trough.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/2009/publication-6414.pdf

Présentation d'une carte gravimétrique de l'Atlantique Nord-Est
Provedor de dados: 5
Autores: Lalaut, Philippe; Sibuet, Jean-claude; Williams, Carol.
A compilation of free-air anomalies in the North-East Atlantic based on available gravity data is presented. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1981
URL: http://archimer.ifremer.fr/doc/1981/publication-5329.pdf

Site 398 : Evolution of the west iberian passive continental margin in the framework of the early evolution of the north atlantic ocean
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Ryan, William B.f.
DSDP Site 398 is located on the West Iberian passive continental margin, south of Galicia Bank, 20 km to the south of Vigo Seamount (Figure 1).The kinematic evolution of the Iberian plate is closely controlled by the relative motions of the African, European, and North American plates. A study based on magnetic data and land data was undertaken to better define the relative motion of Iberia with respect to these main plates (Sibuet et al; in preparation).Trapped between these plates, microcontinents such as Galicia Bank and Flemish Cap (located between Iberia and North America) assumed their own relative motions with respect to Iberia and North America during the early evolution of the North Atlantic.Consequently, the initial oceanic circulation between...
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1979
URL: http://archimer.ifremer.fr/doc/1979/publication-5269.pdf

Oceanic mantle reflections in deep seismic profiles offshore Sumatra are faults or fakes
Provedor de dados: 5
Autores: Sibuet, Jean-claude; He, Enyuan; Zhao, Minghui; Pang, Xinming; Klingelhoefer, Frauke.
In the late 90's, some faults identified within oceanic crust were demonstrated to be artifacts arising from out-of-plane scattering along linear sediment-buried fault scarps. Symmetrical mantle reflections observed southwest northern Sumatra on seismic reflection profiles have been identified as faults cutting through the upper mantle down to unprecedented depths reaching similar to 45 km. Seawater being conveyed along sub-vertical re-activated fracture zones (FZs) to the upper mantle, the mantle portions of FZs are serpentinized and act as mirrors for seismic rays. We suggest that the mantle features are not faults but artifacts resulting from out-of-plane reflections on these mirrors. Two perpendicular seismic profiles crossing the same FZ display two...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00516/62771/67173.pdf

Contribution de la gravimétrie à l'étude de la Bretagne et du plateau continental adjacent
Provedor de dados: 5
Autores: Sibuet, Jean-claude.
The detailed interpretation of gravimetric surveys implies a good knowledge of the superficial geology, at least in specific spots such as the basement's outcrops. We now have a geological sketch map as well as an estimate of the thickness of the sedimentary series of the continental shelf off the coasts of Brittany. As a consequence, it is now possible to try and interpret the new map of this region's gravimetric anomalies, based on the terrestrial and marine geological data.
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1972
URL: http://archimer.ifremer.fr/doc/1972/publication-5051.pdf

New gravity and magnetic anomaly maps in the Taiwan-Luzon region and their preliminary interpretation
Provedor de dados: 5
Autores: Hsu, Shu-kun; Liu, Char-shine; Shyu, Chuen-tien; Liu, Shao-yung; Sibuet, Jean-claude; Lallemand, Serge; Wang, Chensung; Reed, Donald.
We have compiled new free-air gravity anomaly (FAA) and magnetic anomaly maps, shedding light on the tectonics in the Taiwan-Luzon region. To have a suitable datum level for both the available gravity and magnetic anomaly data, the set of data from an ACT cruise, conducted during May 27 to June 21, 1996, was chosen as a reference. Based on the cross-over error analysis, all the other data were adjusted accordingly. Some satellite-derived, airborne or land data were also added to the compilation to obtain better coverage. Several major new insights into the Taiwan-Luzon region are revealed by the new maps. (1) A prominent NE-SW trending belt of gravity and magnetic anomalies is present in the onshore and offshore areas of southwestern Taiwan. The Peikang...
Tipo: Text
Palavras-chave: Free-air gravity anomaly; Bouguer anomaly; Magnetic anomaly; Transverse ridge; Fracture zone; Transform fault; Taiwan.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00447/55859/58057.pdf

From intracratonic extension to nature spreading in back arc basins: Examples from the Okinawa, Lau and, North Fiji basins
Provedor de dados: 5
Autores: Auzende, Jean Marie; Boespflug, X; Bougault, Henri; Dosso, Laure; Foucher, Jean-paul; Joron, J-l; Ruellan, Etienne; Sibuet, Jean-claude.
Three cruises (POP 1, SEAPSO 3 and SEAPSO 4) carried out during the "Tour du Monde" of the R.V. Jean Charcot allow us to obtain new structural and geochemical data for the Okinawa, North Fiji and Lau basins. Taken together, the structural and geochemical data illustrate a difference in evolution stages of these sites. The less evolved stage is represented by the Okinawa basin, where accretion is evidence only by volcanic intrusion into a thinned continental crust. The most evolved stage is illustrated in the North Fiji basin, where the present-day accretion can be directly compared to the East Pacific Ridge. The Lau basin displays an intermediate stage with a complex system of accretionary ridges. This difference in the evolution stage is translated in the...
Tipo: Text
Ano: 1990
URL: http://archimer.ifremer.fr/doc/00268/37893/35974.pdf

Thinning of the Goban Spur continental margin and formation of early oceanic crust: Constraints from forward modelling and inversion of marine magnetic anomalies
Provedor de dados: 5
Autores: Louvel, Veronique; Dyment, Jerome; Sibuet, Jean-claude.
The deep seismic reflection profile Western Approaches Margin (WAM) cuts across the Goban Spur continental margin, located southwest of Ireland. This non-volcanic margin is characterized by a few tilted blocks parallel to the margin. A volcanic sill has been emplaced on the westernmost tilted block. The shape of the eastern part of this sill is known from seismic data, but neither seismic nor gravity data allow a precise determination of the extent and shape of the volcanic body at depth. Forward modelling and inversion of magnetic data constrain the shape of this volcanic sill and the location of the ocean-continent transition. The volcanic body thickens towards the ocean, and seems to be in direct contact with the oceanic crust. In the contact zone, the...
Tipo: Text
Palavras-chave: Continental margin; Goban Spur; Magnetic anomalies; Ocean-continent boundary.
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00337/44777/44601.pdf

Geophysical study of the easternmost walvis ridge, south atlantic : morphololy and shallow structure
Provedor de dados: 5
Autores: Goslin, J.; Mascle, Jean; Sibuet, Jean-claude; Hosking, H.
The landward termination of Walvis Ridge consists of two east-trending basement ridges of probable basaltic composition enclosing a relatively important sedimentary basin.  East of long. 10° E., the southern ridge disappears under the sediments of the continental margin. The trends of the basement ridges are in good agreement with the inferred direction of initial opening.  Since its formation, the Walvis Ridge has probably dammed sediment coming from the south. The proposed identification of layer A, a very strong horizon over which the reflectors are nearly undisturbed, may indicate that no major tectonic phase has affected this area since the shift of the pole of opening for the south Atlantic in Late Cretaceous-early Tertiary time. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1974
URL: http://archimer.ifremer.fr/doc/1974/publication-5147.pdf

26th December 2004 great Sumatra-Andaman earthquake: Co-seismic and post-seismic motions in northern Sumatra
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Rangin, C; Le Pichon, X; Singh, S; Cattaneo, Antonio; Graindorge, D; Klingelhoefer, Frauke; Lin, Jing-yi; Malod, Jacques-andre; Maury, Tanguy; Schneider, J; Sultan, Nabil; Umber, Marie; Yamaguchi, H.
Trench-parallel thrust faults verging both landward and seaward were mapped in the portion of wedge located between northern Sumatra and the Indian-Indonesian boundary. The spatial aftershocks distribution of the 26th December 2004 earthquake shows that the post-seismic motion is partitioned along two thrust faults, the Lower and Median Thrust Faults, the latter being right-laterally offset by a N-S lower plate fracture zone located along the 93.6 degrees N meridian. Between February 2005 and August 2005, the upper plate aftershock activity shifted from southeast of this fracture zone to northwest of it, suggesting that the lower plate left-lateral motion along the fracture zone may have induced a shift of the upper plate post-seismic activity along the...
Tipo: Text
Palavras-chave: Active thrust faults; Co seismic rupture; Aftershocks; 2004 Sumatra Andaman earthquake.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3508.pdf

Plate tectonic reconstructions and paleogeographic maps of the central and North Atlantic oceans
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Rouzo, Stephane; Srivastava, Shiri.
We have established a new plate kinematic model of the central and North Atlantic oceans between North America, Africa, Meseta, Iberia, Flemish Cap, and Galicia Bank from Late Triassic to Late Cretaceous to better understand the nature and timing of rifting of Nova Scotia and Morocco conjugate continental margins since Late Triassic. The maps of salt distributions at the Sinemurian-Pliensbachian limit (190 Ma; after salt deposition) and in middle Bajocian (170 Ma) show that an area of the Nova Scotia margin is devoid of allochthonous salt and that an area of similar size located oceanward of the West African Coast Magnetic Anomaly shows salt deposits, suggesting that a portion of the Nova Scotia margin with its overlying salt deposits could have been...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00117/22805/20913.pdf

Histoire tectonique du golfe de gascogne
Provedor de dados: 5
Autores: Sibuet, Jean-claude.
Il y a environ 200 m. a. (millions d'années), le golfe de Gascogne n'existait pas ; les rebords des plateaux continentaux du nord de la péninsule ibérique et de l'Europe étaient jointifs.  Bien que des cassures se soient produites dès la fin du Trias (200 m. a.), le mouvement d'ouverture du golfe de Gascogne aurait commencé dès la fin du Jurassique (136 m. a.) pour se terminer au Crétacé supérieur (80 m. a.).  La péninsule ibérique aurait subi, par rapport à l'Europe, une rotation d'environ 23 degrés autour d'un pôle situé près de Paris.  Du Crétacé supérieur à l'Eocène supérieur (38 m. a.) un mouvement de compression d'une cinquantaine de km d'amplitude,  entre la péninsule ibérique et l'Europe stable, serait responsable de la formation des Pyrénées et...
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1974
URL: http://archimer.ifremer.fr/doc/1974/publication-5134.pdf

Variations of b-values at the western edge of the Ryukyu subduction zone, north-east Taiwan
Provedor de dados: 5
Autores: Lin, Jing-yi; Sibuet, Jean-claude; Hsu, S.
Using earthquakes relocated in north-east Taiwan, we estimated b-value distribution along a cross-section located near the Ryukyu slab edge, and four b-value anomalous areas are evidenced: (1) a high b-value body lying on top of a low Vp, low Vs and high Vp/Vs sausage-like body was considered as a region of enhanced partial melt or water supply above which seismicity occurs; (2) beneath the Ilan Plain, an anomalous area characterized by b-values slightly higher than 1.1 might give evidence to the magma conduits to the Kueishantao Island; (3) above the Ryukyu Wadati-Benioff zone, at depths ranging from 90 to 110 km, a high b-value anomaly might correspond to the depth where dehydration occurs in the subducting oceanic plate; and (4) a low b-value area...
Tipo: Text
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4119.pdf

3D seismic structure of the Zhenbei-Huangyan seamounts chain in the East Sub-basin of the South China Sea and its mechanism of formation
Provedor de dados: 5
Autores: Wang, Jian; Zhao, Minghui; Qiu, Xuelin; Sibuet, Jean-claude; He, Enyuan; Zhang, Jiazheng; Tao, Chunhui.
The probable N055°-oriented extinct spreading ridge of the East Sub-basin is cut across by the post-spreading volcanic ridge oriented approximately E–W in its western part and called the Zhenbei–Huangyan seamounts chain. A three-dimensional ocean bottom seismometer survey was conducted in 2011 and covered both the extinct spreading ridge and the Zhenbei–Huangyan seamounts chain in the East Sub-basin. The comprehensive seismic record sections of 39 ocean bottom seismometers underline the high-quality data with clear and reliable P-wave seismic first arrivals. The three-dimensional tomographic results show that the crust is oceanic on each side of the Zhenbei–Huangyan seamounts chain. The seafloor spreading lineaments and associated fracture zones pattern...
Tipo: Text
Palavras-chave: Extinct spreading ridge; Zhenbei-Huangyan seamounts chain; 3D seismic structure; Post-spreading magmatism; East Sub-basin; South China Sea.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00314/42515/44989.pdf

Dominant structural trends on the western continental margin of iberia : implications on initial rifting
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Berthois, Léopold.
Preparatory to IPOD site surveys for Leg 47B, a provisional bathymetric map was established (three sheets, scaled 1:500,000) for the area West of the Iberian peninsula. This report presents a new version of this bathymetric map (scaled 1:2,400,000 at 41°N) which incorporates data obtained since 1974. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1979
URL: http://archimer.ifremer.fr/doc/1979/publication-5240.pdf

Reply to the comment of Talwani et al. (2017) on the Sibuet et al. (2016) paper entitled “Thinned continental crust intruded by volcanics beneath the northern Bay of Bengal”
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Klingelhoefer, Frauke; Yeh, Yi-ching; Rangin, Claude; Lee, Chao-shing.
The northern Bay of Bengal velocity-depth profiles do not follow the velocity-depth curve of the North Atlantic volcanic margins, and only partially the Kerguelen velocity-depth curves. Deep seismic refraction and reflection profiles acquired across the Hatton bank and Feroes ridge show that the melt is intruded into the lower thinned continental crust as sills, which cross-cut the continental fabric rather than underplating as it was often assumed in the past. Compared with the SCS northern margin proxy, we still suggest that the BoB crust is thinned continental crust intruded by post-rifting volcanics, as also shown by the interpretation of the numerous high-quality deep MCS profiles we collected there. What was supposed to be underplating might be sills...
Tipo: Text
Palavras-chave: Northern Bay of Bengal; Wide-angle and reflection seismic profiles; Multichannel seismic profiles; Thinned continental crust intruded by; Volcanics.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00393/50459/51192.pdf

The ocean-continent boundary off the western continental margin of Iberia: Crustal structure west of Galicia Bank
Provedor de dados: 5
Autores: Whitmarsh, Robert B; White, Robert S; Horsefield, Susan J; Sibuet, Jean-claude; Recq, Maurice; Louvel, Veronique.
A seismic refraction transect across the Galicia Bank continental margin shows that the original continental crust thins westward from 17 to 2 km immediately east of a margin-parallel peridotite ridge (PR). immediately west of the PR, oceanic crust is only 2.5-3.5 km thick, but farther west (oceanward) it thickens to 7 km. The PR caps a similar to 60-km-wide lens-shaped serpentinized peridotite body underlying both thinned continental and thin oceanic crust. When superimposed on a reflection time version of the velocity model, the S reflector is clearly intracrustal at its east end. Westward, S cuts down to lower crustal levels, eventually coinciding with the top of the serpentinized peridotite lens (original crust-mantle boundary). These observations...
Tipo: Text
Ano: 1996
URL: http://archimer.ifremer.fr/doc/00281/39255/43277.pdf

Tectonic significance of the Taitung Canyon, Huatung Basin, east of Taiwan (vol 25, pg 95, 2004)
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Hsu, Shu-kun; Normand, Alain.
Since the beginning of formation of Proto-Taiwan, the subducting Philippine (PH) Sea plate has moved continuously through time in the N307° direction with respect to Eurasia (EU), tearing the EU plate. The subducting EU plate includes a continental part in the north and an oceanic part in the south. The boundary B between these two domains corresponds to the eastern prolongation of the northeastern South China Sea ocean-continent transition zone. In the Huatung Basin (east of Taiwan), the Taitung Canyon is N065° oriented and is close and parallel to B. Seismic profiles show that the southern flank of the canyon corresponds to a fault with a normal component of a few tens of meters in the sediments and possible dextral shearing. Several crustal earthquakes...
Tipo: Text
Palavras-chave: Underlying slab deformation along trasition zone; Slip fault; Right lateral strike; Taitung Canyon.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-3035.pdf

South armorican shear zone and continental fit before the opening of the bay of biscay
Provedor de dados: 5
Autores: Sibuet, Jean-claude.
The relative position of continents prior to the opening of the Bay of Biscay can be correctly deduced from reconstruction of the Ibero-Armoncan belt only if the extent of the Late-Hercynian horizontal displacement along the south Armorican shear zone and perhaps also along the north Pyrenean fault can be determined. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1973
URL: http://archimer.ifremer.fr/doc/1973/publication-5060.pdf

Thickness of lithosphere deduced from gravity edge effects across the Mendocino Fault
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Le Pichon, Xavier; Goslin, Jean.
THE evolution of a lithospheric plate, as it migrates away from the accreting boundary (mid-ocean ridge crest), is mostly a result of vertical cooling by conduction. As density is a function of temperature and pressure, the density structure should be a function of the age of the plate and, in order to preserve isostatic equilibrium, the seafloor should subside as the plate cools. Thus, the variation of heat flow, seafloor depth and the gravity field are different expressions of the same process, progressive cooling, occurring over the whole thickness of the plate. Sclater and Francheteau² have verified these properties through an analysis of the variation of heat flow and depth with the age of the plate. Their model assumed that the plate remains a...
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1974
URL: http://archimer.ifremer.fr/doc/1974/publication-5430.pdf

Pyrenean orogeny and plate kinematics - art. no. B08104
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Srivastava, Sp; Spakman, W.
The evolution of the Pyrenees, a mountain range between Iberia and Eurasia, has remained the subject of many debates between geologists and geophysicists for a long time. By combining the identification of seafloor spreading anomalies A33o to M0 in the Bay of Biscay with those in the North Atlantic, we have derived a position of a mean pole of rotation for the entire opening of the Bay of Biscay. Four hundred kilometers of shortening took place between the Iberian and Eurasian plates in the Pyrenean domain during the opening of the Bay of Biscay, from chrons M0 to A33o time (118 to 80 Ma). The deep seismic Etude Continentale et Oceanique par Reflexion et refraction Sismique (ECORS) profile shot across the Pyrenees and teleseismic data show the presence of...
Tipo: Text
Palavras-chave: Pyrenean evolution; Kinematics; Seismic data; Tomography.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00000/10837/7748.pdf

Melting features along the Ryukyu slab tear, beneath the southwestern Okinawa Trough - art. no. L19607
Provedor de dados: 5
Autores: Lin, Jing-yi; Hsu, Sk; Sibuet, Jean-claude.
The present-day active volcanic front associated with the Ryukyu subduction zone extends from Japan to the Ilan plain (northern Taiwan) and is located within the Okinawa Trough, 80-100 km above the Ryukyu slab. An abnormal amount of arc volcanism, which consists of basalt, andesite and rhyolite occurs within the southwestern Okinawa Trough, above a slab tear of the Ryukyu subduction zone (CBVT). The power spectrum analysis of magnetic data shows the occurrence of a thin crust above the slab tear and a thick crust beneath this volcanic area. We suggest that an excess of H2O-rich fluid might occur at the slab tear and might increase the melt flux. Both are conveyed obliquely to the uppermost mantle and lower crust CBVT magmas. After interactions, basaltic...
Tipo: Text
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00000/10868/7754.pdf

Impact of lower plate structure on upper plate deformation at the NW Sumatran convergent margin from seafloor morphology
Provedor de dados: 5
Autores: Graindorge, D; Klingelhoefer, Frauke; Sibuet, Jean-claude; Mcneill, L; Henstock, T; Dean, S; Gutscher, M; Dessa, J; Permana, H; Singh, S; Leau, H; White, N; Carton, H; Malod, Jacques-andre; Rangin, C; Aryawan, K; Chaubey, A; Chauhan, A; Galih, D; Greenroyd, C; Laesanpura, A; Prihantono, J; Royle, G; Shankar, U.
We present results from multibeam bathymetric data acquired during 2005 and 2006, in the region of maximum slip of the 26 Dec. 2004 earthquake (Mw 9.2). These data provide high-resolution images of seafloor morphology of the entire NW Sumatra forearc from the Sunda trench to the submarine volcanic arc just north of Sumatra. A slope gradient analysis of the combined dataset accurately highlights those portions of the seafloor shaped by active tectonic, depositional and/or erosional processes. The greatest slope gradients are located in the frontal 30 km of the forearc, at the toe of the accretionary wedge. This suggests that long-term deformation rates are highest here and that probably only minor amounts of slip are accommodated by other thrust faults...
Tipo: Text
Palavras-chave: Sumatra; Tectonic; Seafloor morphology; Accretionary wedge; Subduction.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-5166.pdf

Interprétation gravimétrique des zones de fractures
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Veyrat-peiney, Bernard.
A vertical distribution of temperatures in the lithosphere allows us to generate a simple gravimetric model which closely matches the observed free-air anomaly across oceanic fracture zones. Topographic highs associated with fracture zones are not compensated in the active transform part but become progressively compensated in the fossil part. At distances corresponding to a period of 10 to 20 m.y., compensation is complete. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1976
URL: http://archimer.ifremer.fr/doc/1976/publication-5001.pdf

Distribution of the East China Sea continental shelf basins and depths of magnetic sources
Provedor de dados: 5
Autores: Lin, Jing-yi; Sibuet, Jean-claude; Hsu, S.
The acoustic basement map of the East China Sea, established by the Shanghai Offshore Petroleum Bureau with all available industry seismic data, shows the existence of a 30-km-wide, 10-km-deep basin, that we named the Ho Basin. The Ho Basin belongs to a series of elongated deep basins extending over 600 km east of the Taiwan-Sinzi Ridge and flanked to the East by a ridge named the Longwan Ridge in its northern part. This new system of basin and ridge was probably formed during middle Miocene, sometimes in between rifting episodes occurring in the Taipei Basin and Okinawa Trough. It. complements the already defined system of five belts of back-arc basins and associated arc volcanic ridges in the East China Sea, which are progressively younger from the...
Tipo: Text
Palavras-chave: Depth of magnetic sources; Spectral analysis; Backarc basins; East China Sea.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-1342.pdf

Geodynamics of the South China Sea
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Yeh, Yi-ching; Lee, Chao-shing.
The beginning of seafloor spreading in the South China Sea (SCS) is now established from IODP drilling Leg 349 at 33 Ma. Chron 12 (32 Ma) is the oldest chron identified in the SCS. The nature of the crust of the northeastern part of the SCS located north of chron C12, where chrons 15 to 17 were previously identified, is not oceanic but thinned continental crust intruded by volcanic elongated features emplaced 17-22 Ma ago. Based on magnetic anomalies identifications, the end of the SCS spreading could be either 15.5, 20.5 Ma (Briais et al., 1993; Barckhausen et al., 2014) or something else. However, as post-spreading magmatic activity (~ 13-3.5 Ma) largely masks the spreading fabric in particular near the axis of the east sub-basin, published locations of...
Tipo: Text
Palavras-chave: South China Sea; Gravity; Magnetics; Structural and tectonic analyses; Kinematics.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00316/42686/42059.pdf

Structure and rifting evolution of the northern Newfoundland Basin from Erable multichannel seismic reflection profiles across the southeastern margin of Flemish Cap
Provedor de dados: 5
Autores: Welford, J. K.; Smith, J. A.; Hall, J.; Deemer, S.; Srivastava, S. P.; Sibuet, Jean-claude.
We present the results from processing and interpreting five lines from the 1992 Erable multichannel seismic reflection experiment extending from the southeastern margin of Flemish Cap into the northern Newfoundland Basin. These profiles reveal significant along strike variations in the rifting styles experienced by Flemish Cap. In the southwest, a 100-km-wide transition zone is identified between thinned continental crust and thin oceanic crust. Similar to the conjugate Galicia Bank and Iberian margins, this transition zone contains a section of deep basement adjacent to a series of shallower ridges and is interpreted as exhumed serpentinized mantle. Along strike towards the northeast, this transition zone pinches out completely within 100 km and is...
Tipo: Text
Palavras-chave: Controlled source seismology; Submarine tectonics and volcanism; Continental margins: divergent; Continental tectonics: extensional; Crustal structure; Atlantic Ocean.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00001/11202/7876.pdf

Deep drilling results of Leg 47b (Galicia Bank area) in the framework of the early evolution of the North Atlantic Ocean
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Ryan, W. B. F.; Arthur, M.; Barnes, R.; Blechsmidt, G.; De Charpal, O.; De Graciansky, P. C.; Habib, D.; Iaccarino, S.; Johnson, D.; Lopatin, B. G.; Maldonado, A.; Montadert, L.; Moore, D. G.; Morgan, G. E.; Mountain, G.; Rehault, J. P.; Sigal, J.; William, C. A.
Lithologic and stratigraphic evidence from D.S.D.P. Site 398 (3910 m water depth, 1740 m total penetration) and regional seismic reflexion data are placed in the context of the early tectonic evolution of the North Atlantic ocean. The morphology of the western Iberian continental margin is the result of two main tensional episodes dated Permo-Lias and Upper Jurassic - Lower Cretaceous, during which the initial basins between Grand Banks and Iberia were created by subsidence and tilting of continental blocks. A limited oceanic opening had probably occurred in Jurassic time between these two tensional episodes. There was no relative motion during Lower Cretaceous between North America and Iberia. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1980
URL: http://archimer.ifremer.fr/doc/1980/publication-5394.pdf

Geophysical constraints on the lithospheric structure in the northeastern South China Sea and its implications for the South China Sea geodynamics
Provedor de dados: 5
Autores: Liu, Siqing; Zhao, Minghui; Sibuet, Jean-claude; Qiu, Xuelin; Wu, Jonny; Zhang, Jiazheng; Chen, Chuanxu; Xu, Ya; Sun, Longtao.
An E-W oriented OBS2015-2 wide-angle refraction profile was shot in the northeastern South China Sea (SCS) between refraction profiles T1 and T2 in order to better understand the variability of the crustal composition and the role of specific tectonic features. P-wave velocity models established from forward and inversion modeling imaged a 12 to 15 km-thick thinned continental crust and a high velocity layer (HVL) in the lower crust which is interpreted as magmatic underplating. Profile OBS2015-2 cut across the Taiwan transfer zone (TTZ), which separates two consecutive rifted segments of different orientations in the northeastern SCS. The TTZ is a well-defined upper crustal feature characterized by a HVL with different thickness on both sides. We have...
Tipo: Text
Palavras-chave: Northeastern South China Sea; Continent-ocean boundary (COB); Wide-angle reflection/refraction data; Thinned continental crust intruded by post-rifting volcanism; Taiwan transfer zone (TTZ).
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00443/55458/56974.pdf

Spatial variations in the frequency-magnitude distribution of earthquakes in the southwestern Okinawa Trough
Provedor de dados: 5
Autores: Lin, Jing-yi; Sibuet, Jean-claude; Lee, Chao-shing; Hsu, Shu-kun; Klingelhoefer, Frauke.
The relations between the frequency of occurrence and the magnitude of earthquakes are established in the southern Okinawa Trough for 2823 relocated earthquakes recorded during a passive ocean bottom seismometer experiment. Three high b-values areas are identified: (1) for an area offshore of the Ilan Plain, south of the andesitic Kueishantao Island from a depth of 50 km to the surface, thereby confirming the subduction component of the island andesites; (2) for a body lying along the 123.3 degrees E meridian at depths ranging from 0 to 50 km that may reflect the high temperature inflow rising up from a slab tear; (3) for a third cylindrical body about 15 km in diameter beneath the Cross Backarc Volcanic Trail, at depths ranging from 0 to 15 km. This...
Tipo: Text
Palavras-chave: Magma chamber; Slab tear; Southern Okinawa Trough backarc basin; B Values.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3036.pdf

Thinned continental crust intruded by volcanics beneath the northern Bay of Bengal
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Klingelhoefer, Frauke; Huang, Yuan-ping; Yeh, Yi-ching; Rangin, Claude; Lee, Chao-shing; Hsu, Shu-kun.
Since the early Cretaceous, the Bay of Bengal was formed during rifting between India and Antarctica and then by subsequent seafloor spreading. The nature of the crust underlying the Bay of Bengal is oceanic south of 15°N, but remains unknown (thinned continental crust, serpentinized mantle or oceanic crust) north of this limit. In order to better define the nature of the crust in the northern Bay of Bengal, three wide-angle reflection seismic and refraction profiles were acquired during the multichannel seismic reflection Bengal cruise. Nine ocean-bottom seismometers were deployed alternatively on three profiles. A seismic source consisting of 64 air guns with a volume of 6180 in3 was used simultaneously with a 10.05-km long streamer to acquire both...
Tipo: Text
Palavras-chave: Northern Bay of Bengal; Wide-angle seismic reflection and refraction data; Thinned continental crust intruded by volcanics.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00345/45571/45180.pdf

Mouvements verticaux dans la région des bancs de Galice (Atlantique nord-est) d'après les résultats du Leg 47 B
Provedor de dados: 5
Autores: Sibuet, Jean-claude; De Cahrpal, Olivier; Montadert, Lucien; Ryan, William B.f.
The morphology of the Western Iberian Continental margin is the result of two main tensional episodes dated Permian-Lias and Upper Jurassic-Lower Cretaceous. Locally, at the level of D.S.D.P. site 398, this second episode is dated Barremian to Uppermost Aptian. A limited oceanic opening probably occurred in Middle Jurassic time between these two tensional episodes. During Lower Cretaceous, there was no relative movement between North America and Iberia. Seafloor spreading began again in Uppermost Aptian and has continued to the present day. The paleodepth for site 398 should have been around two kilometers in Lower Cretaceous after the last movements of subsidence and tilting of blocks associated with the so-called Upper Jurassic-Lower Cretaceous tensional...
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1978
URL: http://archimer.ifremer.fr/doc/1978/publication-5235.pdf

Okinawa trough backarc basin: Early tectonic and magmatic evolution
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Deffontaines, Benoît; Hsu, Shu-kun; Thareau, Nicolas; Le Formal, Jean-pierre; Liu, Char-shine; Act Party,.
The Okinawa Trough, lying between Japan and Taiwan, is a backarc basin formed by extension within the continental lithosphere behind the Ryukyu trench-are system. Stress directions associated with the two last extensional phases in the southwestern Okinawa Trough have been deduced from a comparison with analog modeling: the direction of extension is N150 degrees for the Pleistocene phase of extension (2-0.1 Ma) and N170 degrees for the late Pleistocene-Holocene phase of extension (0.1-0 Ma). The present-day Ryukyu volcanic are, a narrow continuous feature extending from Japan to Taiwan, is located on the eastern side of the Okinawa Trough, 80-100 km above the Wadati-Benioff zone, the minimum depth for emplacement of are magmatism. Scarce present-day...
Tipo: Text
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00448/55932/57773.pdf

Geophysical study of the easternmost Walvis Ridge, South Atlantic: Deep structure
Provedor de dados: 5
Autores: Goslin, J.; Sibuet, Jean-claude.
A seismic-refraction study of the sedimentary structure of the South West African continental shelf was carried out between lat 17°S and 24°S using expendable sonobuoys. Striking differences exist both in the topography and sedimentary structure between the shelf north and south of the Walvis Ridge. South of the ridge, as far as lat 23°S, the shelf consists of a prograded series, whereas north of the ridge, at least as far as lat 17°S, east-trending canyons cut the shelf sedimentary cover. The steep northem scarp of Walvis Ridge can be traced eastward under the sediment of the continental margin. The southern flank of the ridge is buried under a thicker sedimentary cover and could only be traced eastward to long. 10°E on seismic-reflection records. This...
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1975
URL: http://archimer.ifremer.fr/doc/1975/publication-4978.pdf

Crustal structure across the post-spreading magmatic ridge of the East Sub-basin in the South China Sea: Tectonic significance
Provedor de dados: 5
Autores: He, Enyuan; Zhao, Minghui; Qiu, Xuelin; Sibuet, Jean-claude; Wang, Jian; Zhang, Jiazheng.
The 140-km wide last phase of opening of the South China Sea (SCS) corresponds to a N145° direction of spreading with rift features identified on swath bathymetric data trending N055° (Sibuet et al., 2016). These N055° seafloor spreading features of the East Sub-basin are cut across by a post-spreading volcanic ridge oriented approximately E-W in its western part (Zhenbei-Huangyan seamounts chain). The knowledge of the deep crustal structure beneath this volcanic ridge is essential to elucidate not only the formation and tectonic evolution of the SCS, but also the mechanism of emplacement of the post-spreading magmatism. We use air-gun shots recorded by ocean bottom seismometers to image the deep crustal structure along the N-S oriented G8G0 seismic...
Tipo: Text
Palavras-chave: East Sub-basin of the South China Sea; Zhenbei Huangyan seamounts chain; 2-D crustal structure; Post-spreading magmatism.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00317/42858/42284.pdf

Structure across the northeastern margin of Flemish Cap, offshore Newfoundland from Erable multichannel seismic reflection profiles: evidence for a transtensional rifting environment
Provedor de dados: 5
Autores: Welford, J. Kim; Hall, Jeremy; Sibuet, Jean-claude; Srivastava, Shiri P.
P&gt;We present the results from processing and interpreting nine multichannel seismic reflection lines collected during the 1992 Erable experiment over the northeastern margin of Flemish Cap offshore Newfoundland. These lines, combined into five cross-sections, provide increased seismic coverage over this lightly probed section of the margin and reveal tectonically significant along-strike variations in the degree and compartmentalization of crustal thinning. Similar to the southeastern margins of Flemish Cap and the Grand Banks, a transitional zone of exhumed serpentinized mantle is interpreted between thinned continental and oceanic crust. The 25 km wide transitional zone bears similarities to the 120 km wide transitional zone interpreted as exhumed...
Tipo: Text
Palavras-chave: Controlled source seismology; Continental margins: divergent; Continental tectonics: extensional; Submarine tectonics and volcanism; Crustal structure; Atlantic Ocean.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00017/12776/11313.pdf

A schematic model of the evolution of the south atlantic
Provedor de dados: 5
Autores: Le Pichon, Xavier; Melguen, M.; Sibuet, Jean-claude.
A schematic model of the evolution of the South Atlantic ocean is proposed to demonstrate the possibilities offered by the Deep Sea Drilling Project within the framework of Plate Tectonics to reconstruct a logical evolution of the history of the ocean basins and their paleoenvironment. The emphasis is put on the methodology available to reconstruct the ocean crust morphology and its sedimentary cover at all stages throughout the opening of the ocean.Paleobathymetric, deep paleo-water-circulation and paleo-sedimentary - facies maps at five different stages of the opening are presented and discussed. The last type of maps are in great part based on a new paleo - Carbonate Compensation Depth Curve for the South Atlantic which is tentatively proposed here....
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1978
URL: http://archimer.ifremer.fr/doc/1978/publication-5196.pdf

Histoire structurale du golfe de Gascogne
Provedor de dados: 5
Autores: Sibuet, Jean-claude.
La précision des mesures gravimétriques en mer est souvent difficile à estimer du fait de la multiplicité des causes d'erreurs. Bien que La précision recherchée ou affirmée soit de quelques milligals, il n'est pas rare de trouver des valeurs de l'anomalie à l'air libre différant de plusieurs dizaines de milligals aux intersections de profils exécutés sur des navires différents.
Tipo: Text
Ano: 1972
URL: http://archimer.ifremer.fr/doc/00034/14539/11816.pdf

Exhumed mantle-forming transitional crust in the Newfoundland-Iberia rift and associated magnetic anomalies - art. no. B06105
Provedor de dados: 5
Autores: Sibuet, Jean-claude; Srivastava, Shiri; Manatschal, Gianreto.
[1] Transitional zones located between Iberia and North America formed during continental rifting and mostly consist of exhumed mantle. In this study we show that ages of exhumed mantle at Ocean Drilling Program (ODP) sites 1068 and 1070 in the Iberia Abyssal Plain and site 1277 in the Newfoundland Basin are similar to ages determined from magnetic lineations created by serpentinization during mantle exhumation. On the basis of paleomagnetic and geological data and a comparison with a fossil ocean-continent transition in the Alps, we envisage a first episode of mantle serpentinization during which a strong component of magnetization was acquired followed by a second episode occurring at the contact with cold seawater, and which only affects the upper tens...
Tipo: Text
Palavras-chave: Magnetic anomalies; Newfoundland Iberia rift; Exhumed mantle.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3015.pdf

Paléoenvironnement de l'Atlantique sud
Provedor de dados: 5
Autores: Melguen, Marthe; Le Pichon, Xavier; Sibuet, Jean-claude.
A schematic model of the evolution of the South Atlantic paleoenvironment since the early Cretaceous is proposed. The reconstruction here proposed is based on all the data offered for the South Atlantic by the Deep-Sea Drilling Project. These data are integrated within the framework of Plate Tectonics. The emphasis is put on the methodology available to reconstruct the ocean crust morphology and its sedimentary cover throughout the opennig of the ocean. Paleobathymetric, paleocirculation and paleofacies maps are presented. The paleofacies maps are in great part based on a new paleo-CCD (paleo-calcite compensation depth) curve, which is tentatively proposed here for the South Atlantic. During the early Cretaceous the South Atlantic consisted of two narrow...
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1978
URL: http://archimer.ifremer.fr/doc/1978/publication-5234.pdf

Contribution à l'étude des mécanismes de formation des marges continentales passives
Provedor de dados: 5
Autores: Sibuet, Jean-claude.
Based on the geological and geophysical data on North-East Atlantic margins, the aim of this study is to define the directions of the extension of the different margin segments, and then to constrain the margin formation models in order to try and quantify the extension. The proposed scheme is to try and integrate the available geological and geophysical constraints, keeping in mind that the future data on the deep structure of the margins could quickly lead us to reconsider it. The first kinematical consequences of this scheme are examined. (unverified OCR)
Tipo: Text
Ano: 1987
URL: http://archimer.ifremer.fr/doc/1987/these-3753.pdf

Variations in heat flow across the Goban Spur and Galicia Bank continental margins
Provedor de dados: 5
Autores: Louden, K. E; Sibuet, Jean-claude; Foucher, Jean-paul.
We present the results of 44 new heat flow stations which were taken in 1984 and 1989 in profiles across the Goban Spur and Galicia Bank continental margins (NW Atlantic Ocean). Simple extensional models indicate that the heat flow across both these Early Cretaceous rifted margins should increase from values of 45-50 mW/m2 over oceanic crust to 65-80 mW/m2 on the continents. The rate of this increase should help to constrain the mechanism (simple versus pure shear) by which the upper, more radiogenic continental crust is thinned. Measurements across Goban Spur increase from values of 40-45 mW/m2 over oceanic crust to 50-55 mW/m2 near the continental shelf. They follow the predicted trend for pure-shear rifting, but only if the value of upper crustal...
Tipo: Text
Ano: 1991
URL: http://archimer.ifremer.fr/doc/00182/29341/28269.pdf