Alpine tectono‐metamorphic evolution of the Corsica basement

The Alpine orogenic edifice of Corsica (northern Tyrrhenian Sea) offers thepossibility to investigate the mode through which continental crust respondsto the propagation of regional shortening at convergent plate margins. Thegeology of Corsica has been traditionally described as separating domainsaffected by the Alpine tectonism (Alpine Corsica) from those that did not expe-rience the Alpine tectono-metamorphic overprint (Hercynian Corsica), butrecent studies show that most of Hercynian Corsica was thermally reset inpost-Eocene times, questioning this paradigm. The continental units formed atthe expenses of the stretched continental margin of the European plate andconsist of Hercynian granitoid basement rocks and cover sequences (Permianvolcaniclastics and Mesozoic sedimentary successions). By integrating meso-and microstructural investigations with metamorphic thermobarometry and40Ar–39Ar geochronology along three E–W trending structural transectsrunning across the basement section exposed below the Alpine orogenicwedge, we document middle-late Eocene (c. 50–33 Ma) westward-vergingsyn-metamorphic (low-grade blueschist facies) thick-skinned, basement-involved thrusting. Significantly, crustal shortening in the continentalbasement predated of c. 15–10 Ma the subduction zone metamorphism in theoceanic-derived Schistes Lustrés Complex. When the P–T–t–deformationhistory as reconstructed from the Corsica basement is integrated with theregional scenario of the Alpine–Apennine orogeny, a tectonic reconstruction isproposed, which frames the Alpine orogeny in Corsica within the Apennine–Maghrebian subduction system in the retroside (retrowedge) of the Apennineorogenic wedge.