Key geological features of Alpine Corsica (modified from Gueydan et al., 2017) a. Schematic sketch of Western Alps and Corsica, showing the Alpine wedge, the major thrusts and basins, as well as Oligo-Miocene extensional basins in South-East France, in the Lyon Gulf and in Corsica. b. Regional geological map of Alpine Corsica with major lithological units shown in the tectonic log in inset. The “Schistes Lustrés” are composed from bottom to top of three main units i.e. Castagnicia (mainly meta-sediments), Lower Oceanic Unit (serpentinites and metabasalts) and Upper Oceanic Unit (serpentinites, metagabbros, and continental slices). The contacts between units are thrusts. The studied zone (violet star in both the tectonic log and the map) is in Marina di Giotanni and occurs in metagabbros in the Upper oceanic units. Oligo-Miocene brittle-ductile normal faults are shown (grey for Oligocene, red for early Miocene and blue for late Miocene, see details in Gueydan et al., 2017). c/ East-West schematic cross section (location in b/ as AA’ profile in dark grey dashed line) showing the tectonic nappe piles acquired during subduction (associated with top to NE shearing, blue arrow). Red arrows for exhumation sense of shearing. See text for references and explanations. The studied shear zones (violet star) is on top of the tectonic nappe piles (Upper Oceanic unit) and with top to E/NE shearing (red arrow).