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Consulta: subjectFacets:"Crustal structure"
Registros recuperados: 17
Data/hora: 09/06/2017 10:23:09
Crustal structure of the basin and ridge system west of New Caledonia (southwest Pacific) from
wide-angle and reflection seismic data.
Provedor de dados: 5
Autores: 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
Crustal structure of the NE Rockall Trough from wide-angle seismic data modeling - art. no. B11105
Provedor de dados: 5
Autores: Klingelhoefer, Frauke; Edwards, R; Hobbs, R; England, R.
[1] Two wide-angle seismic lines located in the northern Rockall Trough were acquired in May 2000. One line ( line E) crosses
the trough from the continental shelf off Lewis to normal oceanic crust west of Lousy Bank in NW-SE direction. The other line (
line D) intersects with line E, crosses the Wyville-Thomson Ridge in a SW-NE direction and ends in the Faeroe-Shetland Basin.
Sonobuoy data and expanding spread profiles acquired in the same area have been remodeled. Analysis of the seismic data using
travel times and amplitudes reveals an up to 5 km thick sedimentary basin including an up to 1.5 km thick basaltic layer which is
present in most of the trough. Further conclusions of this study are that the Rockall Trough is underlain by highly stretched...
Tipo: Text
Palavras-chave: Crustal structure; Wide angle seismics; Rockall Trough.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-881.pdf
Deep crustal structure across a young passive margin from wide-angle and reflection seismic data
(The SARDINIA Experiment) - I. Gulf of Lion's margin
Provedor de dados: 5
Autores: 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
Deep structure of the Santos Basin-São Paulo Plateau System, SE Brazil
Provedor de dados: 5
Autores: 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
Geological constraints on the evolution of the Angolan margin based on reflection and refraction
seismic data (ZaïAngo project)
Provedor de dados: 5
Autores: 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: http://archimer.ifremer.fr/doc/2005/publication-349.pdf
Geophysical evidence for a transform margin offshore Western Algeria: a witness of a
subduction-transform edge propagator?
Provedor de dados: 5
Autores: Badji, Rabia; Charvis, Philippe; Bracene, Rabah; Galve, Audrey; Badsi, Madjid; Ribodetti, Alessandra; Benaissa, Zahia;
Klingelhoefer, Frauke; Medaouri, Mourad; Beslier, Marie-odile.
For the first time, a deep seismic data set acquired in the frame of the Algerian-French SPIRAL program provides new insights
regarding the origin of the westernmost Algerian margin and basin. We performed a tomographic inversion of traveltimes along a
100-km-long wide-angle seismic profile shot over 40 ocean bottom seismometers offshore Mostaganem (Northwestern Algeria).
The resulting velocity model and multichannel seismic reflection profiles show a thin (3-4 km thick) oceanic crust. The narrow
ocean-continent transition (less than 10 km wide) is bounded by vertical faults and surmounted by a narrow almost continuous
basin filled with Miocene to Quaternary sediments. This fault system, as well as the faults organized in a negative-flower structure
on the...
Tipo: Text
Palavras-chave: Seismic tomography; Continental margins: transform; Crustal structure; Africa; Europe.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00255/36670/35278.pdf
Imaging proto-oceanic crust off the Brazilian Continental Margin
Provedor de dados: 5
Autores: 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
La marge sud-marocaine et les premières phases d'ouverture de l'océan Atlantique Central
Provedor de dados: 5
Autores: Labails, Cinthia.
We here propose a twofold approach to study the continental margins of the Central Atlantic Ocean, with special focus on the
South Morocco Margin, in front of Reguibat bloc. This approach is based on plate kinematics reconstructions and geological field
studies to map and constrain the geometry of the plate boundary though time and seismic sections (reflection and refraction) to
decipher the tectonic and sedimentary history of the margin.
Sahabi et al. (2004) recently showed that the opening of the central
Atlantic Ocean started 195 my ago (Sinemurian basis) (i.e. 20 my later than what was generally proposed in earlier models).
Based on this result and on the analysis of geophysical data (including new seismic lines, a new magnetic anomaly grid and...
Tipo: Text
Palavras-chave: Tectonic inheritance; Combined wide angle and deep reflection seismic; South Moroccan margin; Crustal
structure; Non volcanic continental passive margin; Héritage tectonique; Sismique réflexion et réfraction; Structure crustale;
Marge continentale passive Sud Maroc.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/these-3791.pdf
Limits of the seismogenic zone in the epicentral region of the 26 December 2004 great
Sumatra-Andaman earthquake: Results from seismic refraction and wide-angle reflection surveys
and thermal modeling
Provedor de dados: 5
Autores: Klingelhoefer, Frauke; Gutscher, M. -a.; Ladage, S.; Dessa, J. -x.; Graindorge, D.; Franke, D.; Andre, Camille; Permana,
H.; Yudistira, T.; Chauhan, A.
The 26 December 2004 Sumatra earthquake (M-w = 9.1) initiated around 30 km depth and ruptured 1300 km of the
Indo-Australian-Sunda plate boundary. During the Sumatra-OBS (ocean bottom seismometer) survey, a wide-angle seismic
profile was acquired across the epicentral region. A seismic velocity model was obtained from combined travel time tomography
and forward modeling. Together with reflection seismic data from the SeaCause II cruise, the deep structure of the source region
of the great earthquake is revealed. Four to five kilometers of sediments overlie the oceanic crust at the trench, and the subducting
slab can be imaged down to a depth of 35 km. We find a crystalline backstop 120 km from the trench axis, below the fore-arc
basin. A high-velocity zone...
Tipo: Text
Palavras-chave: Middle america trench; Fore arc basin; Bottom seismographic observation; Subduction zone; Crustal structure;
Accretionary prism; Mantle serpentinization; Aftershock distribution; Megathrust earthquakes; Velocity structure.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00000/11155/7737.pdf
Multiphased tectonic evolution of the Central Algerian margin from combined wide-angle and
reflection seismic data off Tipaza, Algeria
Provedor de dados: 5
Autores: 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
Seismic evidence for plume-derived volcanism during formation of the continental margin in southern
Davis Strait and northern Labrador Sea
Provedor de dados: 5
Autores: Gerlings, Joanna; Funck, Thomas; Jackson, H. Ruth; Louden, Keith E.; Klingerhoefer, Frauke.
The crustal structure in the southern Davis Strait and the adjacent ocean-continent transition zone in NE Labrador Sea was
determined along a 185-km-long refraction/wide-angle reflection seismic transect to study the impact of the Iceland mantle plume
to this region. A P-wave velocity model was developed from forward and inverse modelling of dense airgun shots recorded by
ocean bottom seismographs. A coincident industry multichannel reflection seismic profile was used to guide the modelling as
reflectivity could be identified down to Moho. The model displays a marked lateral change of velocity structure. The sedimentary
cover (velocities 1.8-3.9 km s(-1)) is up to 4 km thick in the north and thins to 1 km in the south. The segment of the line within...
Tipo: Text
Palavras-chave: Crustal structure; Hotspots; Continental margins: transform; Continental margins: divergent.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6848.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>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
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>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
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
Structure of the Gabon Margin from integrated seismic reflection and gravity data
Provedor de dados: 5
Autores: Dupre, Stephanie; Cloetingh, Sierd; Bertotti, Giovanni.
In the South Gabon Basin, deep multi-channel seismic reflection and gravity modeling analysis have shed light on key features of
the structure of the margin. The thinned continental crust beneath the Gabon Margin appears to be composed of two distinct
layers, separated by a clear, strong and more or less continuous reflector running in the 7–10 s TWT window. The lower crust is
characterized by a higher density, intermediate between the lower values of the upper crust and the denser values of the mantle.
The lower crust is irregularly shaped and presents lateral thickness variations along the direction of thinning and along the coast.
In the offshore thinned continental domain, the lower and upper crust form a 20–25 km thick body. Crustal thicknesses point...
Tipo: Text
Palavras-chave: Deep seismic; Gravity modeling; Crustal structure; Rifted continental margins; Lower crust; Gabon Margin.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00039/15020/12347.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: http://archimer.ifremer.fr/doc/2009/publication-6414.pdf
The crustal structure of the north-eastern Gulf of Aden continental margin: insights from wide-angle
seismic data
Provedor de dados: 5
Autores: Watremez, Louise; Leroy, Sylvie; Rouzo, Stephane; D'Acremont, E.; Unternehr, P.; Ebinger, C.; Lucazeau, F.; Al-lazki,
A.
P>The wide-angle seismic (WAS) and gravity data of the Encens survey allow us to determine the deep crustal structure of the
north-eastern Gulf of Aden non-volcanic passive margin. The Gulf of Aden is a young oceanic basin that began to open at least
17.6 Ma ago. Its current geometry shows first- and second-order segmentation: our study focusses on the Ashawq-Salalah
second-order segment, between Alula-Fartak and Socotra-Hadbeen fracture zones. Modelling of the WAS and gravity data (three
profiles across and three along the margin) gives insights into the first- and second-order structures. (1) Continental thinning is
abrupt (15-20 km thinning across 50-100 km distance). It is accommodated by several tilted blocks. (2) The ocean-continent
transition...
Tipo: Text
Palavras-chave: Controlled source seismology; Continental margins: divergent; Crustal structure; Indian Ocean.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00200/31102/29507.pdf