The Arzacq-Western Pyrenees ECORS Deep Seismic Profile

Daignières, M.; Séguret, M.; Specht, M.; Team, Ecors

doi:10.1007/978-3-642-78849-9_15

Cited by 58 publications

(64 citation statements)

References 17 publications

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“…The observations do not support the Lakora thrust dipping north to offset the lower crust and Moho (e.g. Daignières et al 1994;Jammes et al, 2009), nor they provide evidence for the Guarga thrust (Fig. 16C) oversteepening downwards to link with the lower crust and Moho offset (e.g.…”

Section: Accepted Manuscriptmentioning

confidence: 86%

“…Another debatable point resides in the southward extension of lower crustal and Moho reflections in the adjacent ECORS-Arzacq profile. Certainly, the deep crustal reflectivity is weak along the entire reflection line (Daignières et al, 1994), but discontinuous reflections at 8-10 s TWT (not weaker than in much of the rest of the profile) interpreted as the Moho can be traced until below the Mendibelza massif in the southern end of the profile (Teixell, 1998) (Fig. 10), and thus cross-cutting the geometry postulated by Wang et al (2016).…”

Section: Significance Of High-density Bodies In the Crustmentioning

confidence: 93%

“…This section line runs 10-15 km east of the Ansó-Arzacq crustal transect of Teixell (1998), and construction details are given in Teixell et al (2016). Descriptions and references of the surface geology can be found in Labaume et al (1985), Teixell (1996) and Lagabrielle et al (2010), and the deep structure derives from the projection of the ECORS-Arzacq and PYROPE W geophysical profiles (Daignières et al, 1994; resulting from the rising and downbuilding of diapiric salt walls and minibasins (Canérot, 1988;Labaume and Teixell, 2014). The underlying basement can be inferred to dip northwards, cut by thrust faults, until it attains the regional elevation of the Aquitaine basin ( Fig.…”

Section: The Chaînons Béarnais-jaca Sectionmentioning

confidence: 99%

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Crustal structure and evolution of the Pyrenean-Cantabrian belt: A review and new interpretations from recent concepts and data

et al. 2018

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International audienceThis paper provides a synthesis of current data and interpretations on the crustal structure of the Pyrenean-Cantabrian orogenic belt, and presents new tectonic models for representative transects. The Pyrenean orogeny lasted from Santonian (~84 Ma) to early Miocene times (~20 Ma), and consisted of a spatial and temporal succession of oceanic crust/exhumed mantle subduction, rift inversion and continental collision processes at the Iberia-Eurasia plate boundary. A good coverage by active-source (vertical-incidence and wide-angle reflection) and passive-source (receiver functions) seismic studies, coupled with surface data have led to a reasonable knowledge of the present-day crustal architecture of the Pyrenean-Cantabrian belt, although questions remain. Seismic imaging reveals a persistent structure, from the central Pyrenees to the central Cantabrian Mountains, consisting of a wedge of Eurasian lithosphere indented into the thicker Iberian plate, whose lower crust is detached and plunges northwards into the mantle. For the Pyrenees, a new scheme of relationships between the southern upper crustal thrust sheets and the Axial Zone is here proposed. For the Cantabrian belt, the depth reached by the N-dipping Iberian crust and the structure of the margin are also revised.The common occurrence of lherzolite bodies in the northern Pyrenees and the seismic velocity and potential field record of the Bay of Biscay indicate that the precursor of the Pyrenees was a hyperextended and strongly segmented rift system, where narrow domains of exhumed mantle separated the thinned Iberian and Eurasian continental margins since the Albian-Cenomanian. The exhumed mantle in the Pyrenean rift was largely covered by a Mesozoic sedimentary lid that had locally glided along detachments in Triassic evaporites. Continental margin collision in the Pyrenees was preceded by subduction of the exhumed mantle, accompanied by the pop-up thrust expulsion of the off-scraped sedimentary lid above. To the west, oceanic subduction of the Bay of Biscay under the North Iberian margin is supported by an upper plate thrust wedge, gravity and magnetic anomalies, and 3D inclined sub-crustal reflections. However, discrepancies remain for the location of continent-ocean transitions in the Bay of Biscay and for the extent of oceanic subduction. The plate-kinematic evolution during the Mesozoic, which involves issues as the timing and total amount of opening, as well as the role of strike-slip drift, is also under debate, discrepancies arising from first-order interpretations of the adjacent oceanic magnetic anomaly record

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Section: Accepted Manuscriptmentioning

confidence: 86%

Section: Significance Of High-density Bodies In the Crustmentioning

confidence: 93%

Section: The Chaînons Béarnais-jaca Sectionmentioning

confidence: 99%

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Crustal structure and evolution of the Pyrenean-Cantabrian belt: A review and new interpretations from recent concepts and data

et al. 2018

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“…The tectonic knowledge of the Pyrenees benefitted greatly more than 20 years ago from the acquisition of the ECORS deep seismic reflection profiles Daignières et al, 1994). Subsequent crustal-scale models for the Pyrenean orogeny included restored sections to the preorogenic state that depicted a Mesozoic rift basin floored by a thinned continental crust (Roure et al, 1989;Muñoz, 1992;Teixell, 1998;Beaumont et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

The crustal evolution of the west-central Pyrenees revisited: Inferences from a new kinematic scenario

Teixell¹,

Labaume

Lagabrielle

2016

Comptes Rendus. Géoscience

145

250

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New evolutionary models for the Pyrenean orogeny must consider feedbacks between the midCretaceous hyperextension postulated recently and the Pyrenean inversion. We present a new crustal section of the Pyrenees through the Jaca basin, the western Axial Zone and the Chaînons Béarnais which allows identifying the ancient continental margins of the Iberian and European plates and a suture. A sequential restoration allows a reassessment of the style of convergence through time. Restoration leads to a progressively thinned crust in narrow continental margins separated by a domain of exhumed mantle peridotite and overlain by a detached sedimentary lid. Early convergence during the late Cretaceous and earliest Paleogene was accommodated by subduction of the peridotite domain. This was followed in the Eocene by initial collision involving overriding of the Iberian margin onto the European margin along the deep ramp of the NorthPyrenean Frontal thrust, which defines the suture. Subsequent full collision and strong relief generation from the late Eocene to the early Miocene were associated to thrust accretion of the Iberian plate, underlain by wedging and northward subduction of decoupled Iberian lower crust.

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“…1), from the Mendibelza Massif to the south to the Arzacq Basin to the north (Daignières et al 1994). Beneath the Mendibelza Massif, the Iberian Moho is dipping towards the north.…”

Section: Introductionmentioning

confidence: 99%

The Pyrenean architecture as revealed by teleseismic P-to-S converted waves recorded along two dense transects

Chevrot¹,

Sylvander²,

Díaz³

et al. 2015

Geophysical Journal International

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S U M M A R YBetween 2011 and 2013, two dense transects were deployed across the central and western Pyrenees to get better constraints on the deep lithospheric architecture and discriminate the competing models of the structure and formation of the Pyrenees. Each transect recorded the regional and global seismicity during a period of approximately 1 yr. Here, we exploit the records of teleseismic compressional waves and of their conversions to shear waves on internal discontinuities in order to map lithospheric interfaces beneath the two transects. The migrated sections, obtained by performing common conversion point stacks, are in remarkable agreement with the results of the ECORS-Pyrenees and ECORS-Arzacq deep seismic surveys. However, the migrations of converted waves reveal new details of the deep lithospheric architecture that could not be seen with the active source experiments. The new images provide clear and definite evidence for the subduction of a thinned Iberian crust down to at least ∼70 km depth, a result that has important implications for the formation of the Pyrenees. The subduction of the Iberian lithosphere leads to reconsider the amount of convergence between Iberia and Europe during the Cenozoic. A recent regional P-wave tomography, relying on the data of the PYROPE and IBERARRAY temporary experiments, revealed the segmentation of lithospheric structures by inherited Hercynian NE-SW transfer faults that were reactivated during the Albian rifting. Our migration images are consistent with this model, and give further support to the idea that the Pyrenees were produced by the tectonic inversion of a segmented hyperextended rift that was buried by subduction beneath the European Plate.

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The Arzacq-Western Pyrenees ECORS Deep Seismic Profile

Cited by 58 publications

References 17 publications

Crustal structure and evolution of the Pyrenean-Cantabrian belt: A review and new interpretations from recent concepts and data

Crustal structure and evolution of the Pyrenean-Cantabrian belt: A review and new interpretations from recent concepts and data

The crustal evolution of the west-central Pyrenees revisited: Inferences from a new kinematic scenario

The Pyrenean architecture as revealed by teleseismic P-to-S converted waves recorded along two dense transects

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