Exhumation and tilting of the late Herchynian continental crust in the Serre Massif (Southern Calabria, Italy)

In the Serre Massif (Calabria-Peloritani arc) a nearly complete tilted section of the Hercynian continental crust is exposed. The upper levels crop out in the Stilo area (southeastern Serre) and they consist of very low- to low-grade metamorphic phyllites with interbedded marbles and metavolcanic rocks of Ordovician to Carboniferous age. These rocks are intruded by late Hercynian granodiorites. The sedimentary cover is represented, from the bottom upwards, by: Jurassic shallow water limestones; Late Chattian-Burdigalian conglomeratic turbidites (Stilo-Capo d'Orlando Fm.); Serravallian-Tortonian conglomerates and arenites; Zanclean silty clays, argillaceous marls and silts (Trubi Fm.). Jurassic and Cenozoic sediments plunge southeastwards and the dip angle progressively decreases with the younging direction. In the present research an exhumation path for the upper Hercynian crust cropping out in the Stilo zone is traced. Igneous thermobarometry (Al-in-hornblende barometry and hornblende-plagioclase thermometry) was adopted to obtain the depth of the granodiorite at the time of emplacement. Then, sequentially restoring a NW-SE oriented geological section, the exhumation history of the granodiorite was unravelled, from the Present to the Paleozoic. The progressive back-rotations permitted to obtain the depth of the granodiorite at the age of the considered stratigraphic surface and to collect dept-time data useful to trace the exhumation path. The exhumation history of the Stilo granodiorite is characterised by two main episodes separated by a nearly static tectonic phase. The first episode took place from Late Carboniferous to earliest Jurassic and is poorly constrained by stratigraphic records. The second episode, well documented by the stratigraphic records, developed from Oligocene to Present and it is also characterised by episodic subsidence stages. A total amount of 43° southeastward tilting mostly took place from Late Oligocene to Pleistocene. Therefore, a continuous tectonic process from Oligocene to Present is suggested to explain the collected data. The extensional tectonics connected to the eastward migration of the Apenninic Arc played a key role in the tilting of the Serre crustal section.