The Curinga–Girifalco Line in the framework of the tectonic evolution of the remnant Alpine chain in Calabria (southern Italy)

In the peri-Mediterranean metamorphic belts, the tectonic evolution of the Calabria–Peloritani terrane during the dominant compressive tectonics of the Eocene represents one of the most problematic points in palinspastic restorations. A matter of particular debate is its shortening, which could have occurred during the Alpine or the Apennine subduction. In this regard, a crucial joint is provided by the kinematics of one of the most relevant shear zones such as the Curinga–Girifalco Line, cropping out in central Calabria. This shear zone juxtaposed a nearly complete Hercynian crustal section (i.e. the Sila and Serre Unit) onto the remnants of the Castagna Unit. The data in the available literature on ductile kinematics from the south-eastern branch of the Curinga–Girifalco Line indicate a downward movement of the hanging wall. In the present paper we show new, ductile kinematic data and petrographic evidence from outcrops in the north-western and south-eastern branches of the Curinga–Girifalco Line. Our results highlight the coherent kinematics of the Eocene shortening during the Alpine subduction system, followed by (late Eocene?)Oligocene to early Miocene, dominantly ductile extensional reworking, relating to the Apennines subduction system.