Role of rift structural inheritance in orogeny highlighted by the Western Pyrenees case-study

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Evolution of a low convergence collisional orogen: a review of Pyrenean orogenesis

The Pyrenees is a collisional orogen built by inversion of an immature rift system during convergence of the Iberian and European plates from Late Cretaceous to late Cenozoic. The full mountain belt consists of the pro-foreland southern Pyrenees and the retro-foreland northern Pyrenees, where the inverted lower Cretaceous rift system is mainly preserved. Due to low overall convergence and absence of oceanic subduction, this orogen preserves one of the best geological records of early orogenesis, the transition from early convergence to main collision and the transition from collision to post-convergence. During these transitional periods major changes in orogen behavior reflect evolving lithospheric processes and tectonic drivers. Contributions by the OROGEN project have shed new light on these critical periods, on the evolution of the orogen as a whole, and in particular on the early convergence stage. By integrating results of OROGEN with those of other recent collaborative projects in the Pyrenean domain (e.g., PYRAMID, PYROPE, RGF-Pyrénées), this paper offers a synthesis of current knowledge and debate on the evolution of this immature orogen as recorded in the synorogenic basins and fold and thrust belts of both the upper European and lower Iberian plates. Expanding insight on the role of salt tectonics at local to regional scales is summarised and discussed. Uncertainties involved in data compilation across a whole orogen using different datasets are discussed, for example for deriving shortening values and distribution

Racial differences in systemic sclerosis disease presentation: a European Scleroderma Trials and Research group study

Objectives. Racial factors play a significant role in SSc. We evaluated differences in SSc presentations between white patients (WP), Asian patients (AP) and black patients (BP) and analysed the effects of geographical locations.Methods. SSc characteristics of patients from the EUSTAR cohort were cross-sectionally compared across racial groups using survival and multiple logistic regression analyses.Results. The study included 9162 WP, 341 AP and 181 BP. AP developed the first non-RP feature faster than WP but slower than BP. AP were less frequently anti-centromere (ACA; odds ratio (OR) = 0.4, P < 0.001) and more frequently anti-topoisomerase-I autoantibodies (ATA) positive (OR = 1.2, P = 0.068), while BP were less likely to be ACA and ATA positive than were WP [OR(ACA) = 0.3, P < 0.001; OR(ATA) = 0.5, P = 0.020]. AP had less often (OR = 0.7, P = 0.06) and BP more often (OR = 2.7, P < 0.001) diffuse skin involvement than had WP.AP and BP were more likely to have pulmonary hypertension [OR(AP) = 2.6, P < 0.001; OR(BP) = 2.7, P = 0.03 vs WP] and a reduced forced vital capacity [OR(AP) = 2.5, P < 0.001; OR(BP) = 2.4, P < 0.004] than were WP. AP more often had an impaired diffusing capacity of the lung than had BP and WP [OR(AP vs BP) = 1.9, P = 0.038; OR(AP vs WP) = 2.4, P < 0.001]. After RP onset, AP and BP had a higher hazard to die than had WP [hazard ratio (HR) (AP) = 1.6, P = 0.011; HR(BP) = 2.1, P < 0.001].Conclusion. Compared with WP, and mostly independent of geographical location, AP have a faster and earlier disease onset with high prevalences of ATA, pulmonary hypertension and forced vital capacity impairment and higher mortality. BP had the fastest disease onset, a high prevalence of diffuse skin involvement and nominally the highest mortality

The tectono-sedimentary evolution of synrift supra-detachment basins in distal rifted margins,examples of the Samedan basin (central alps, SE Switzerland) and the Mauléon basin (Western pyrenees SW France)

Le rifting continental est un processus polyphasé conduisant non seulement à la création de blocs basculés dans les marges proximales mais également à la mise en place de systèmes de failles de détachement dans les marges dites distales . Les failles dOne of the most effective geodynamical processes creating sedimentary basins is the continental rifting. Investigations performed in deep magma-poor rifted margins showed that the crust can be extremely extended and associated with low-angle detachment f

The tectono-sedimentary evolution of synrift supra-detachment basins in distal rifted margins,examples of the Samedan basin (central alps, SE Switzerland) and the Mauléon basin (Western pyrenees SW France)

Le rifting continental est un processus polyphasé conduisant non seulement à la création de blocs basculés dans les marges proximales mais également à la mise en place de systèmes de failles de détachement dans les marges dites distales . Les failles de détachement exhument leur mur au fond de bassins sédimentaires originaux : les bassins supra-détachement. Bien qu imagés dans les marges actuelles ou décrits dans des analogues fossiles, ils n ont quasiment jamais été explorés. Cette étude s'intéresse à leur développement pendant le rifting sur la base de deux chantiers à terre (alpin et pyrénéen). Cette étude montre qu ils ont une morphologie, une architecture stratigraphique et un remplissage sédimentaire fortement conditionnés par le développement des systèmes de détachement. Ces derniers développent des éléments structuraux dérivés de la délamination de leur toit qui subdivisent les bassins en trois ordres de grandeurs le long de la marge distale. En dépit des échelles différentes, leur enregistrement sédimentaire est la conséquence d'une évolution triphasée : 1) initiation de l'exhumation du mur de faille et développement d'un cortège sédimentaire basal, syn-tectonique, dérivé de son toit ; 2) exhumation et érosion du mur vers l'amont du bassin alimentant le cortège basal ; 3) migration de l'exhumation en dehors du bassin par création d'un nouvel élément structural à l'aval et développement d'une séquence syn-rift post-tectonique remplissant passivement le bassin. Cette dernière, coupée de la source d'origine tectonique, est dépendante d'une connexion avec un flux sédimentaire externe et de son importance au regard de l'accommodation post-tectonique.One of the most effective geodynamical processes creating sedimentary basins is the continental rifting. Investigations performed in deep magma-poor rifted margins showed that the crust can be extremely extended and associated with low-angle detachment faulting. Therefore, the tectono-sedimentary models developed for classical hemigrabens of the most proximal domains of the margins cannot be applied to the distal margins. Unfortunately, due to access issues, this evolution remains poorly understood. This is the aim of this study focused on two fossil analogues (Alps and Pyrenees). Palinspastic restoration helped to restore the post-rift architecture of this type of basins preserving their syn-rift sedimentary record. This study shows that supra-detachment basins are controlled by the detachment faults flooring rift-basins. They are bounded by structural elements resulting from the hangingwall delamination during active exhumation (allochthons or detachment breakaway blocks). A syn-rift trilogy evolution can be observed as: 1) Onset of exhumation, with the hangingwall rupture during the basin opening over the exhumed fault plane. Deposition of hangingwall-derived basal facies tract. 2) Widening of the basin accommodated by the upstream footwall exhumation controls a source change to footwall derived deposits. 3) Tectonic cessation through the basin leads to develop the post-tectonic sequence consisting of passive infilling. Because of the cessation of active exhumation as the engine of the syn-rift gravity flows along the fault, this sequence is strongly dependent of a potential incoming sediment flux and its efficiency compare to post-tectonic space accommodation

L' évolution tectono-sédimentaire syn-rift des bassins de marge passive profonde (Exemples du bassin de samedan (Alpes centrales, Suisse) et du bassin de Mauléon (Pyrénées basques françaises))

Le rifting continental est un processus polyphasé conduisant non seulement à la création de blocs basculés dans les marges proximales mais également à la mise en place de systèmes de failles de détachement dans les marges dites distales . Les failles de détachement exhument leur mur au fond de bassins sédimentaires originaux : les bassins supra-détachement. Bien qu imagés dans les marges actuelles ou décrits dans des analogues fossiles, ils n ont quasiment jamais été explorés. Cette étude s intéresse à leur développement pendant le rifting sur la base de deux chantiers à terre (alpin et pyrénéen). Cette étude montre qu ils ont une morphologie, une architecture stratigraphique et un remplissage sédimentaire fortement conditionnés par le développement des systèmes de détachement. Ces derniers développent des éléments structuraux dérivés de la délamination de leur toit qui subdivisent les bassins en trois ordres de grandeurs le long de la marge distale. En dépit des échelles différentes, leur enregistrement sédimentaire est la conséquence d une évolution triphasée : 1) initiation de l exhumation du mur de faille et développement d un cortège sédimentaire basal, syn-tectonique, dérivé de son toit ; 2) exhumation et érosion du mur vers l'amont du bassin alimentant le cortège basal ; 3) migration de l exhumation en dehors du bassin par création d un nouvel élément structural à l aval et développement d une séquence syn-rift post-tectonique remplissant passivement le bassin. Cette dernière, coupée de la source d origine tectonique, est dépendante d une connexion avec un flux sédimentaire externe et de son importance au regard de l accommodation post-tectonique.One of the most effective geodynamical processes creating sedimentary basins is the continental rifting. Investigations performed in deep magma-poor rifted margins showed that the crust can be extremely extended and associated with low-angle detachment faulting. Therefore, the tectono-sedimentary models developed for classical hemigrabens of the most proximal domains of the margins cannot be applied to the distal margins. Unfortunately, due to access issues, this evolution remains poorly understood. This is the aim of this study focused on two fossil analogues (Alps and Pyrenees). Palinspastic restoration helped to restore the post-rift architecture of this type of basins preserving their syn-rift sedimentary record. This study shows that supra-detachment basins are controlled by the detachment faults flooring rift-basins. They are bounded by structural elements resulting from the hangingwall delamination during active exhumation (allochthons or detachment breakaway blocks). A syn-rift trilogy evolution can be observed as: 1) Onset of exhumation, with the hangingwall rupture during the basin opening over the exhumed fault plane. Deposition of hangingwall-derived basal facies tract. 2) Widening of the basin accommodated by the upstream footwall exhumation controls a source change to footwall derived deposits. 3) Tectonic cessation through the basin leads to develop the post-tectonic sequence consisting of passive infilling. Because of the cessation of active exhumation as the engine of the syn-rift gravity flows along the fault, this sequence is strongly dependent of a potential incoming sediment flux and its efficiency compare to post-tectonic space accommodation.STRASBOURG-Géologie (674822251) / SudocSudocFranceF

The Err detachment in SE Switzerland: a witness of how continents break apart.

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A reconstruction of Iberia accounting for Western Tethys-North Atlantic kinematics since the late-Permian-Triassic

International audienceThe western European kinematic evolution results from the opening of the western Neotethys and the Atlantic oceans since the late Paleozoic and the Mesozoic. Geological evidence shows that the Iberian domain recorded the propagation of these two oceanic systems well and is therefore a key to significantly advancing our understanding of the regional plate reconstructions. The late-Permian-Triassic Iberian rift basins have accommodated extension, but this tectonic stage is often neglected in most plate kinematic models, leading to the overestimation of the movements between Iberia and Europe during the subsequent Mesozoic (Early Cretaceous) rift phase. By compiling existing seismic profiles and geological constraints along the North Atlantic margins, including well data over Iberia, as well as recently published kinematic and paleogeographic reconstructions, we propose a coherent kinematic model of Iberia that accounts for both the Neotethyan and Atlantic evolutions. Our model shows that the Europe-Iberia plate boundary was a domain of distributed and oblique extension made of two rift systems in the Pyrenees and in the Iberian intra-continental basins. It differs from standard models that consider left-lateral strike-slip movement localized only in the northern Pyrenees in introducing a significant strike-slip movement south of the Ebro block. At a larger scale it emphasizes the role played by the late-Permian-Triassic rift and magmatism, as well as strike-slip faulting in the evolution of the western Neotethys Ocean and their control on the development of the Atlantic rift