Seismicity in central-western Pyrenees (France): A consequence of the subsidence of dense exhumed bodies

Souriau, Annie; Rigo, Alexis; Sylvander, Matthieu; Benahmed, Sébastien; Grimaud, Frank

doi:10.1016/j.tecto.2014.02.008

Cited by 20 publications

(33 citation statements)

References 48 publications

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“…2), which is characterized by normal-fault focal mechanisms, may represent extensional sinking of this dense body (e.g. Souriau et al 2014), although its shape and depth extent are largely unknown. Following the image of the ECORS-Pyrenees profile (Roure et al, 1989), we have represented the body as a thrust slice of lower crust, which we tentatively placed as a dismembered piece of Iberian lower crust in the restoration.…”

Section: Discussionmentioning

confidence: 99%

“…The deep crustal structure is based on the interpretation of the ECORS-Arzacq seismic reflection profile and on receiver functions analysis of the PYROPE and older surveys (see text). The stippled area represents the cluster of microseisms characteristic of the North-Pyrenean Zone projected after Souriau et al (2014), where the vertical precision of the seismic event location is of 3 km (Dumont et al, 2015). Inset boxes represent key features of the Mesozoic and Cenozoic basins for the reconstruction of the preorogenic architecture shown in …”

Section: Discussionmentioning

confidence: 99%

“…Following inferences from the east and from the mylonitic deformation of basement blocks in the Triassic of the CBB (Corre et al, this volume), a network of anastomosed shear zones are sketched in Figure 3, representing a ductile extensional duplex stretching the upper crust in the distal margins. Lozenge-shaped bodies may have included lower crustal boudins, which were later incorporated in the North-Pyrenean basement and are now attested by gravity (Casas et al, 1997;Souriau et al, 2014). The width of the Pyrenean margins deduced from section restoration (<40 km) is comparable to some present-day, non-inverted passive margin tracts as the continental slope of the Armorican margin (Thinon et al, 2003), although they are markedly narrower than others like the South Atlantic margins (e.g.…”

Section: A Model For the Cretaceous Basinmentioning

confidence: 94%

“…A system of south-verging basement thrusts involving upper Paleozoic rocks under the Bedous unit and CBB, not exposed in the study transect, are schematically projected from observations in the Aspe and Ossau valleys, a few km east of the section. Under the northern CBB, a shallow slice of lower crust or mantle material is inferred from a Bouguer gravity high (Casas et al, 1997;Souriau et al, 2014). A north-dipping seismic band is reported to the south of the gravity anomaly (Souriau et al, 2014).…”

Section: Section Of the West-central Pyrenees: Identification Of Ancimentioning

confidence: 96%

“…Under the northern CBB, a shallow slice of lower crust or mantle material is inferred from a Bouguer gravity high (Casas et al, 1997;Souriau et al, 2014). A north-dipping seismic band is reported to the south of the gravity anomaly (Souriau et al, 2014). At the northern edge of the CBB, the North Pyrenean Frontal thrust (NPFT) appears in the MesozoicPaleogene succession as an imbricate fan of north-verging thrusts, poorly emergent to the surface (Biteau et al, 2006), and here pictured according to an unpublished section (courtesy of TOTAL).…”

Section: Section Of the West-central Pyrenees: Identification Of Ancimentioning

confidence: 99%

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

Teixell¹,

Labaume

Lagabrielle

2016

Comptes Rendus. Géoscience

136

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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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: A Model For the Cretaceous Basinmentioning

confidence: 94%

Section: Section Of the West-central Pyrenees: Identification Of Ancimentioning

confidence: 96%

Section: Section Of the West-central Pyrenees: Identification Of Ancimentioning

confidence: 99%

See 3 more Smart Citations

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

Teixell¹,

Labaume

Lagabrielle

2016

Comptes Rendus. Géoscience

136

250

View full text Add to dashboard Cite

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Microseismicity of the Béarn range: Reactivation of inversion and collision structures at the northern edge of the Iberian plate

et al. 2015

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The Béarn range, located to the north of the Axial Zone in the Western Pyrenees, is affected by numerous small-magnitude seismic events. These events overlap an area characterized by specific geological structures which are interpreted to have resulted from multistage extensional and compressional deformation. An analysis of surface geology draped over digital elevation model, together with field investigations, allow identification of two main shortening episodes with differing direction of contraction: D1 represents the inversion of the North Pyrenean Basin, whose Mesozoic infill was detached from highly extended crust and transported southward over the necking zone and the northern margin of the Iberian plate; D2 corresponds to the collision stage and is characterized in the study area by backfolding and backthrusting deformation coeval with uplift in the axial part of the chain due to thickening of the Iberian plate. The microseismicity appears to concentrate along the basal part of the inverted basin units (D1) where this initially low angle thrust has been tilted and steepened during collision (D2). We propose that local steepening of this ancient inversion structure, which should not be named "North Pyrenean Fault," provided the suitable dip for extensional solicitation in association with the present uplift of the Axial Zone, whatever the driving mechanism of this uplift could be.

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Modeling deep control pulsing ﬂux of native H2 throughout tectonic fault-valve systems

Donzé

Bourdet

Truche

et al. 2022

Preprint

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Pulsing seepages of native hydrogen (H2) have been observed at the surface on several emitting structures. It is still unclear whether this H2 pulsed flux is controlled by deep migration processes, atmosphere/near-surface interactions or by bacterial fermentation. Here, we investigate mechanisms that may trigger pulsating fluid migration at depth and the resulting periodicity. We set up a numerical model to simulate the migration of a deep constant fluid flow. To verify the model's formulation to solve complex fluid flows, we first simulate the morphology and amplitude of 2D thermal anomalies induced by buoyancy-driven water flow within a fault zone. Then, we simulate the H2 gas flow along a 1-km draining fault, crosscut by a lower permeable rock layer to investigate the conditions for which a pulsing system is generated from a deep control. For a constant incoming flow of H2 at depth, persistent bursts at the surface only appear in the model if: (I) a permeability with an effective-stress dependency is used, (II) a strong contrast of permeability exists between the different zones, (III) a sufficiently high value of the initial effective stress state at the base of the low permeable layer exists, and (IV) the incoming and continuous fluid flow of H2 at depth remains low enough so that the overpressure does not "open" instantly the low permeability layer. The typical periodicity expected for this type of valve-fault control of H2 pulses at the surface is at a time scale of the order of 100 to 300 days. Hosted fileessoar.10512945.1.docx available at https://authorea.com/users/527803/articles/611174modeling-deep-control-pulsing-%EF%AC%82ux-of-native-h2-throughout-tectonic-fault-valvesystems Modeling deep control pulsing flux of native H 2 throughout tectonic fault-valve systems

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Seismicity in central-western Pyrenees (France): A consequence of the subsidence of dense exhumed bodies

Cited by 20 publications

References 48 publications

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

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

Microseismicity of the Béarn range: Reactivation of inversion and collision structures at the northern edge of the Iberian plate

Modeling deep control pulsing ﬂux of native H2 throughout tectonic fault-valve systems

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