TY - JOUR T1 - LiDAR offshore structural mapping and U/Pb zircon/monazite dating of Variscan strain in the Leon metamorphic domain, NW Brittany A1 - Le Gall,Bernard A1 - Authemayou,Christine A1 - Ehrhold,Axel A1 - Paquette,Jean-Louis A1 - Bussien,Denise A1 - Chazot,Gilles A1 - Aouizerat,Arthur A1 - Pastol,Yves AD - Inst Univ Europeen Mer, UMR CNRS6538, Domaines Ocean, F-29280 Plouzane, France. AD - IFREMER, Ctr Brest, Unite Rech GM, Lab Environm Sedimentaires, F-29280 Plouzane, France. AD - CNRS, UMR6524, Lab Magmas & Volcans, F-63038 Clermont Ferrand, France. AD - Univ Clermont Ferrand, F-63038 Clermont Ferrand, France. AD - Serv Hydrog & Oceanog Marine, F-29228 Brest, France. UR - https://doi.org/10.1016/j.tecto.2014.05.026 DO - 10.1016/j.tecto.2014.05.026 KW - Armorican massif KW - Leon metamorphic domain KW - Offshore structural mapping KW - LiDAR records KW - Dextral ductile shearing KW - U/Pb zircon/monazite dating N2 - 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 magmatic intrusions (St-Renan granite and an offshore gabbro-diorite complex) dated at 314-320 Ma by new U-Th/Pb ages. It post-dated an early regional foliation related to top-to-the-NE ductile transpresional shearing. Our study emphasizes the key role of strike-slip tectonics in the NW part of the Armorica Variscan belt. Y1 - 2014/09 PB - Elsevier Science Bv JF - Tectonophysics SN - 0040-1951 VL - 630 SP - 236 EP - 250 ID - 30490 ER -