BELLAHSEN , Nicolas

This study proposes a reappraisal of the role of the basement tectonics in the structuration of the Alpine foreland,across the Castellane fold-and-thrust belt located in southwestern Alps. We construct three 30 km length N–Sbalanced cross-sections across the entire fold-and-thrust belt, in order to quantify the amount of horizontalshortening...

Le programme du Référentiel Géologique de la France (RGF), coordonné par le BRGM (https://rgf.brgm.fr) vise à fournir une information géologique 3D, numérique, homogène et cohérente sur l'ensemble du territoire national. La vocation du RGF est d'être un système d'information globale impliquant l'ensemble de la communauté scientifique pour...

New lithospheric analog models of oblique rifting presented here capture the main characteristics of natural oblique rifts and provide insights into the fault evolution, basin segmentation, and mantle exhumation occurring during rift localization. We present two models: one with a preexisting oblique lithospheric weakness (model B) and another...

The geometry and kinematics of rifts are strongly controlled by pre-existing structures that may be present in both the crust and the mantle lithosphere. In the Gulf of Aden, the Tertiary oblique rift developed through inherited Mesozoic extensional basins that trend orthogonal to the direction of Oligo-Miocene divergence. Such inheritance may...

The geometry and kinematics of rifts are strongly controlled by pre-existing structures in the lithosphere. Such features may be present in both the crust and the lithosphere mantle. In the oblique Gulf of Aden tertiary rift, inherited mesozoic basins are orthogonal to the direction of Oligo-Miocene divergence. Thus, lateral variations in the...

The geometry and kinematics of rifts are strongly controlled by pre-existing structures in the lithosphere. Such features may be present in both the crust and the lithosphere mantle. In the oblique Gulf of Aden tertiary rift, inherited mesozoic basins are orthogonal to the direction of Oligo-Miocene divergence. Thus, lateral variations in the...

The kinematics of the collision in Western Alps are investigated through five balanced cross sections of the whole external domain from the Oisans to the Mont Blanc massif. These cross sections were built using published data for the Jura and subalpine fold-and-thrust belts and new structural and field analysis for the External Crystalline...

Geological study of the Khan Tengri and Pobedi massifs highlights two phases of compressional fault displacements. A Late Permian/Triassic displacement phase is highlighted (1) by biotite 40 Ar/ 39 Ar ages of 265-256 Ma, suggestive of cooling of Pobedi mid- crustal granulites during >8 km of top-to-the-north motion of the Pobedi Thrust; (2) by...

In the Western Alps, the External Crystalline Massifs (ECM) are key places to investigate the kinematics and thermal structure of a collisional crustal wedge, as their paleo-brittle/ductile transition is now exhumed at the surface. New (U–Th–Sm)/He data on zircon and new Raman Spectroscopy on Carbonaceous Material (RSCM) data from the Aiguilles...

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The tectonic evolution of the Central Asian Orogenic Belt (CAOB) is characterized by the successive accretion of lithospheric blocks, leading to different interpretations about the polarity of subductions during the Paleozoic, the number of microplates and oceanic basins and the timing of tectonic events. This is especially the case in the Tien...

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Magnetic and gravity data gathered during the Encens-Sheba cruise (2000 June) in the eastern Gulf of Aden provide insights on the structural evolution of segmentation from rifted margins to incipient seafloor spreading. In this study, we document the conjugate margins asymmetry, confirm the location of the ocean–continent transition (OCT)...

Rifting between Arabia and Somalia started around 35 Ma followed by spreading at 17.6 Ma in the eastern part of the Gulf of Aden. The first-order segment between Alula-Fartak and Socotra-Hadbeen fracture zones is divided into three second-order segments with different structure and morphology. Seismic reflection data were collected during the...

The structural evolution of the Gulf of Aden passive margins was controlled by its oblique divergence kinematics, inherited structures, and the Afar hot spot. The rifting between Arabia and Somalia started at 35 Ma just before the hot spot paroxysm (at 30Ma) and lasted until 18Ma, when oceanic spreading started. Fieldwork suggests that rift...

The structural evolution of the Gulf of Aden passive margins was controlled by its oblique divergence kinematics, inherited structures, and the Afar hot spot. The rifting between Arabia and Somalia started at 35 Ma just before the hot spot paroxysm (at 30Ma) and lasted until 18Ma, when oceanic spreading started. Fieldwork suggests that rift...

Le but de cette contribution est de documenter et comprendre à la foisla cinématique des déformations collisionelles à l'échelle des Alpes externesoccidentales et le rôle de la structure de la marge européenne danscette structuration orogénique.Dans un premier temps, nous présentons des données nouvelles, structurales,microstructurales et...

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