A seismic study in the Bay of Biscay

Limond, W.Q.; Gray, F.; Grau, G.; Fail, J. P.; Montadert, L.; Patriat, P.

doi:10.1016/0012-821x(74)90125-3

Cited by 8 publications

(8 citation statements)

References 4 publications

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“…Nevertheless, the ESPs were implemented parallel to the main structural trends and it is likely that a 3D data analysis would lead to a similar depth for the crust-mantle discontinuity but could reduce the uncertainty on the velocity values for the deep layers (0.2 km d). As a matter of fact, similar drastic crustal thinning and velocities have been found in the vicinity (Limond et al 1974;Foucher et al 1982). …”

Section: Crustal Velocity Structuresupporting

confidence: 70%

Deep seismic reflection and refraction profiling along the Aquitaine shelf (Bay of Biscay)

Pinet

Montadert

1987

Geophys J Int

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The 300 km ECORS -Bay of Biscay profile was carried out along the Aquitaine shelf and comprised a complete set of experiments including zero-offset and 7.5 km constant offset vertical seismic reflection and six expanding spread profiles. Large offset recordings were fundamental for the definition of the layered lower crust and the Moho, while ESPs provided decisive complementary information for the geological interpretation. These data show a strong variation in crustal thickness from about 20 km beneath the rifted Parentis basin, a failed arm of the oceanic Bay of Biscay, up to 35 km to the north below the Armorican shelf, in the Hercynian domain, and to the south below the Cantabria shelf, in the vicinity of the Pyrenean deformation front. The results have important implications for the behaviour of the crust during the formation of rifted sedimentary basins and during continental collision.

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Section: Crustal Velocity Structuresupporting

confidence: 70%

Deep seismic reflection and refraction profiling along the Aquitaine shelf (Bay of Biscay)

Pinet

Montadert

1987

Geophys J Int

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“…Below the deep margin basin, the inferred thickness of the thinned continental crust, based on the interpretation of free-air anomalies in terms of local as well as regional isostatic equilibrium (Lalaut 1980), is about 3 km. This value is in agreement with the interpretation of a refraction line shot in the deep rnargin basin about 50 km southweastwards of the seismic section of figure 3 (Limond et al 1974). I n summary, the deep margin basin, located on a greatly thinned continental crust about 3 km thick, is, in the absence of sedirnents, a slight geological feature 0.5 km or less deeper than the adjacent oceanic crust.…”

Section: ( B ) (A)supporting

confidence: 90%

The ocean-continent transition in the uniform lithospheric stretching model: role of partial melting in the mantle

1982

Deep Sea Research Part B. Oceanographic Literature Review

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The role of partial melting in the uniform lithospheric stretching model of continental margin formation is explored. I t 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.

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“…Furthermore, the crust is quite thick, appears deformed by faults and includes an upper seismic layer with anomalous low velocities (<5.5 km/s) that overlies a lower seismic layer in which the velocities (7.2–7.3 km/s) [ Ruiz , 2007] are higher than those observed westward in the oceanic layer 3 [ Limond et al , 1974]. For some authors, these features are compatible with a crust which continues being partial or totally oceanic [ Limond et al , 1974; Boillot et al , 1979; Sibuet and Collette , 1993; Alvarez‐Marrón et al , 1995, 1996, 1997]; but, for others, they denote a transitional crust [ Derégnaucourt and Boillot , 1982; Gallastegui , 2000; Ruiz , 2007]. This transitional crust would be in continuation with the transitional crust at the toe of the Armorican slope west of 6°W and would define a transition zone separating the oceanic crust from the Armorican thinned continental crust.…”

Section: Pyrenean and North Foreland Structure In The Eastern Part Ofmentioning

confidence: 99%

“…The continental crust beneath the North Iberian shelf has been affected by the north Pyrenean contractional structures, but yet its thickness decreases from near 27–30 km along the coastline to 20 km at the toe of the continental slope [ Gallart et al , 1997; Pulgar et al , 1996; Fernández‐Viejo et al , 1998; Ruiz , 2007], emphasizing a crustal thinning of the Cantabrian margin during the Late Jurassic‐Early Cretaceous rifting. More to the north, in the Bay of Biscay abyssal plain, the crust of the abyssal plain is much thinner with crustal velocities of an oceanic or transitional crust [ Limond et al , 1974; Fernández‐Viejo , 1997; Ruiz , 2007]. In this area, the refraction seismic Moho is located at a depth of 10–16 km and increases its depth up to 20 km at the toe of the Cantabrian continental slope [ Bacon et al , 1969; Limond et al , 1974; Roberts and Montadert , 1980; Ruiz , 2007].…”

Section: Pyrenean and North Foreland Structure In The Eastern Part Ofmentioning

confidence: 99%

The role of the Bay of Biscay Mesozoic extensional structure in the configuration of the Pyrenean orogen: Constraints from the MARCONI deep seismic reflection survey

et al. 2011

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Seismic interpretation of the MARCONI deep seismic survey enables recognition of the upper crustal structure of the eastern part of the Bay of Biscay and the main features of its Alpine geodynamic evolution. The new data denotes that two domains with different Pyrenean and north foreland structures exist in the Bay of Biscay. In the eastern or Basque‐Parentis Domain, the North Pyrenean front is located close to the Spanish coast, and the northern foreland of the Pyrenees is constituted by a continental crust thinned by a north dipping fault that induced the formation of the Early Cretaceous Parentis Basin. In the western or Cantabrian Domain, the North Pyrenean front is shifted to the north and deforms a narrower and deeper foreland basin which lies on the top of a transitional crust formed from the exhumation of lithospheric mantle along a south dipping extensional low‐angle fault during the Early Cretaceous. The transition between these two domains corresponds to a soft transfer zone linking the shifted North Pyrenean fronts and a north‐ to WNW‐directed thrust that places the continental crust of the Landes Plateau over the transitional crust of the Bay of Biscay abyssal plain. Comparison between this structure and regional data enables characterization of the extensional rift system developed between Iberia and Eurasia during the Late Jurassic and Cretaceous and recognizes that this rift system controlled not only the location and features of the Pyrenean thrust sheets but also the overall structure of this orogen.

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A seismic study in the Bay of Biscay

Cited by 8 publications

References 4 publications

Deep seismic reflection and refraction profiling along the Aquitaine shelf (Bay of Biscay)

Deep seismic reflection and refraction profiling along the Aquitaine shelf (Bay of Biscay)

The ocean-continent transition in the uniform lithospheric stretching model: role of partial melting in the mantle

The role of the Bay of Biscay Mesozoic extensional structure in the configuration of the Pyrenean orogen: Constraints from the MARCONI deep seismic reflection survey

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