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| Authemayou, Christine; Le Gall, Bernard; Caroff, Martial; Bussien Grosjean, Denise. |
| During the Carboniferous collision stage, the West European Variscan orogen was affected by oblique convergence, wrenching, plate-scale oroclinal bending, and widespread exhumation of the deep crust. One of these exhumed units forms the Leon dome located on the northern flank of the Ibero-Armorican Arc in the western part of the Armorican massif. Structural field data from the Ouessant Island reveal kinematic changes between 330 and 300 Ma that affected the northwestern margin of the Leon dome. This margin underwent two ductile deformation phases with opposite strike-slip shear senses. Dextral strike-slip wrenching combined with orogen-normal shortening, orogen-parallel stretching, and local top-to-the-NE shearing occurred during the Leon dome formation... |
| Tipo: Text |
Palavras-chave: Variscan; Armorican massif; Gneiss dome formation; Wrenching; Orogenic syntax; Ouessant Island. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74906/75947.pdf |
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| Le Gall, Bernard; Authemayou, Christine; Ehrhold, Axel; Paquette, Jean-louis; Bussien, Denise; Chazot, Gilles; Aouizerat, Arthur; Pastol, Yves. |
| An exceptional structural picture of the immerged Variscan basement, offshore the Leon metamorphic domain, is supplied by high-resolution LiDAR and echosounder data recorded in the Molene archipelago, western Brittany (France). Various types of fabrics are identified and, from in situ rock sample analyses further combined with field structural data, are interpreted on a lineament trajectory map as the trace of magmatic and tectonic structures. Our onshore/offshore study leads us to propose a two-phase kinematic model that emphasizes the role of a strike-slip duplex in an EW-trending relay zone linking the North Armorican and Pierres Noires ductile shear zones (NASZ, PNSZ). Dextral shearing occurred within a transtensional setting, synchronously with... |
| Tipo: Text |
Palavras-chave: Armorican massif; Leon metamorphic domain; Offshore structural mapping; LiDAR records; Dextral ductile shearing; U/Pb zircon/monazite dating. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00194/30490/28895.pdf |
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