The pull apart-type Tardets-Mauléon Basin, a key to understand the formation of the Pyrenees

Canérot, J.

doi:10.1051/bsgf/2017198

Cited by 31 publications

(39 citation statements)

References 27 publications

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“…From an onshore geological perspective, conclusive kinematic evidence for the direction of basin opening during the Albian-Cenomanian in the Pyrenees is lacking. While pull-apart basin models are proposed by some authors (Choukroune and Mattauer, 1978;Debroas, 1990;Canérot, 2017, and references therein), others argue for an essentially orthogonal extension direction in the broadly E-W-trending North Pyrenean basin (Souquet and Mediavilla, 1976;Johnson and Hall, 1989;Jammes et al, 2009;Masini et al, 2014;Mouthereau et al, 2014). …”

Section: Accepted Manuscriptmentioning

confidence: 99%

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: 99%

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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“…This platform succession terminates with a thick (300-400 m) layer of Upper Aptian limestones (Urgonian facies), and is followed by a thick sequence of Albian to Cenomanian-Turonian flysch deposits (e.g. Debroas, 1978;Debroas et al, 2010;Canérot, 2017aCanérot, , 2017b and references within) preserved within the synclines and marking the main rifting stage. The Chaînons Béarnais range hosts four main lherzolite bodies: the Saraillé and Tos de la Coustette bodies in the southern flank of the Sarrance anticline, the Urdach body at the western tip of the Mail Arrouy anticline, and the Turon de la Técouère body in the strongly tectonized zone of Benou, along the southern border of the Mail-Arrouy thrust structure (Fig.…”

Section: The Chaînons Béarnais and Their Four Mantle Bodies (Fig 2)mentioning

confidence: 99%

“…3 Anatomy of the crust-mantle detachment and cover décollement in the Urdach massif: structure and mineralogy 3.1 Geology of the Urdach massif ( Fig. 4) 3.1.1 Overview of former interpretations The Urdach mantle body lies at the western termination of the Mail Arrouy thrust monocline, between Col d'Urdach and Col d'Etche, and is the easternmost basement exposure of the Mauléon basin (Canérot, 2017a(Canérot, , 2017b. This 1.5-km long lherzolite body is well known for its association with sedimentary breccias of Late Albian age, named the Urdach breccia hereafter (Casteras et al, 1970;Roux, 1983;Debroas et al, 2010).…”

Section: Definition Of the Crust-mantle Detachment And Cover Décollemmentioning

confidence: 99%

Mantle exhumation at magma-poor passive continental margins. Part I. 3D architecture and metasomatic evolution of a fossil exhumed mantle domain (Urdach lherzolite, north-western Pyrenees, France)

Lagabrielle

Asti

Fourcade

et al. 2019

BSGF - Earth Sci. Bull.

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In two companion papers, we report the detailed geological and mineralogical study of two emblematic serpentinized ultramafic bodies of the western North Pyrenean Zone (NPZ), the Urdach massif (this paper) and the Saraillé massif (paper 2). The peridotites have been exhumed to lower crustal levels during the Cretaceous rifting period in the future NPZ. They are associated with Mesozoic pre-rift metamorphic sediments and small units of thinned Paleozoic basement that were deformed during the mantle exhumation event. Based on detailed geological cross-sections and microprobe mineralogical analyses, we describe the lithology of the two major extensional fault zones that accommodated: (i) the progressive exhumation of the lherzolites along the Cretaceous basin axis; (ii) the lateral extraction of the continental crust beneath the rift shoulders and; (iii) the decoupling of the pre-rift cover along the Upper Triassic (Keuper) evaporites and clays, allowing its gliding and conservation in the basin center. These two fault zones are the (lower) crust-mantle detachment and the (upper) cover décollement located respectively at the crust-mantle boundary and at the base of the detached pre-rift cover. The Urdach peridotites were exposed to the seafloor during the Late Albian and underwent local pervasive carbonation and crystallization of calcite in a network of orthogonal veins (ophicalcites). The carbonated serpentinized peridotites were partly covered by debris-flows carrying fragments of both the ultramafics and Paleozoic crustal rocks now forming the polymictic Urdach breccia. The mantle rocks are involved in a Pyrenean overturned fold together with thin units of crustal mylonites. Continent-derived and mantle-derived fluids that circulated along the Urdach crust-mantle detachment led to the crystallization of abundant metasomatic rocks containing quartz, calcite, Cr-rich chlorites, Cr-rich white micas and pyrite. Two samples of metasomatized material from the crust-mantle detachment yielded in situ zircon U/Pb ages of 112.9 ± 1.6 Ma and 109.4 ± 1.2 Ma, thus confirming the Late Albian age of the metasomatic event. The cover décollement is a 30-m thick fault zone which also includes metasomatic rocks of greenschist facies, such as serpentine-calcite association and listvenites, indicating large-scale fluid-rock interactions implying both ultramafic and continental material. The lowermost pre-rift cover is generally missing along the cover décollement due to tectonic disruption during mantle exhumation and continental crust elision. Locally, metasomatized and strongly tectonized Triassic remnants are found as witnesses of the sole at the base of the detached pre-rift cover. We also report the discovery of a spherulitic alkaline lava flow emplaced over the exhumed mantle. These data collectively allow to propose a reconstruction of the architecture and fluid-rock interaction history of the distal domain of the upper Cretaceous northern Iberia margin now inverted in the NPZ.

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“…Up to now, three major interpretations were proposed to account for the geological features of the Urdach area. They involve the following processes: (1) emplacement of large‐scale composite olistolith of mantle‐crustal basement in the Albian‐Cenomanian flyschs along with coarse sedimentary breccia (Duée et al, ; Fortané et al, ); (2) mantle denudation along the Urdach transverse (N‐S) fault scarp zone responsible for the formation of the Mid‐Cretaceous Urdach composite breccia wedge (Canérot, ; Debroas et al, ); and (3) thrusting of a slice of mantle rocks and its cover of tectonosedimentary breccia over verticalized Cretaceous flysch strata (Jammes et al, ; Lagabrielle et al, ).…”

Section: Mapping and Sampling Of The Saraillé And Urdach Paleozoic Unitsmentioning

confidence: 99%

How Do Continents Deform During Mantle Exhumation? Insights From the Northern Iberia Inverted Paleopassive Margin, Western Pyrenees (France)

et al. 2019

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Extreme crustal thinning associated with subcontinental mantle exhumation characterizes the distal domain of some current, magma‐poor continental passive margins. Since these domains lie at abyssal depths and are hardly accessible, their internal structure and the finite strain of the stretched crust are not directly observed and are only inferred. A detailed field study was conducted on exceptionally preserved Cretaceous distal margin analogs in two key areas of the western Pyrenees (North Pyrenean Zone): the Urdach and Saraillé ultramafic massifs in the Chaînons Béarnais range. A tight sampling allowed us to characterize the conditions of the ductile deformation of the continental crust exhumed together with the mantle. New 40Ar/39Ar dating on muscovite constrains the timing of the last deformation of the continental crust in relation with mantle exhumation to the late Albian. We propose a new reconstruction for the distal part of the North Iberian paleopassive margin based on the following constraints: (i) post‐Silurian Paleozoic rocks are never found in the distal domain; (ii) lower crustal levels are not found in the exhumed crustal units; (iii) extension in the pre‐Silurian series is accomplished by lenticular deformation and pervasive ductile flattening through anastomosing extensional mylonitic shear zones at temperatures of 350–450 °C; and (iv) at the final step of exhumation, only pre‐Silurian crustal lenses remained welded on the exhumed mantle. Finally, we discuss the importance of the crustal structure inherited from previous Paleozoic and Mesozoic tectonic events and we state that mantle exhumation was partially achieved before the Cretaceous North Pyrenean rifting.

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The pull apart-type Tardets-Mauléon Basin, a key to understand the formation of the Pyrenees

Cited by 31 publications

References 27 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

Mantle exhumation at magma-poor passive continental margins. Part I. 3D architecture and metasomatic evolution of a fossil exhumed mantle domain (Urdach lherzolite, north-western Pyrenees, France)

How Do Continents Deform During Mantle Exhumation? Insights From the Northern Iberia Inverted Paleopassive Margin, Western Pyrenees (France)

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