Tectonothermal history of the Hercynian continental crust of the Serre (southern Calabria, Italy) monitored by Rb–Sr biotite resetting

Abstract

In the Serre mountains of Calabria, Italy, an exposed section of the continental crust, as left by the Hercynian orogeny, consists of intermediate-lower to upper crustal units. Huge masses of granitoids separate the lower from the upper crustal units. Many mica ages have been obtained from metamorphic and plutonic rocks, which have been interpreted as reflecting continuous cooling or discrete Mesozoic events. A reappraisal of previously determined isotopic data integrated with new Rb± Sr biotite ages is presented and assessed at regional scale to better constrain the post-Hercynian geological evolution of the continental crust of the Serre. The ages cover a wide span of time and form clusters which fit a model involving magmatic, hydrothermal and tectonic events preceding and accompanying the opening and closure of the Tethyan ocean.

Timescales and mechanisms of batholith construction: Constraints from zircon oxygen isotopes and geochronology of the late Variscan Serre Batholith (Calabria, southern Italy)

“…Numerous muscovite and biotite Rb-Sr ages have been reported, including: a) 250-220 Ma and 150-130 Ma for the basal "Squillace tonalite" (Caggianelli et al, 2000;Del Moro et al, 2000); b) 180-130 Ma for the overlying "Cardinale tonalite" (biotite ages: Del Moro et al, 2000); c) 290-250 Ma and 260-190 Ma for the intermediate-level BMPG (Del Moro et al, 1994; d) 288-263 Ma and 280-240 Ma for the shallower BMG (Del Moro et al, 2000;Fornelli et al, 1994), and e) 290-270 Ma for the shallowest BAG (biotite ages: Del Moro et al, 2000;Fornelli et al, 1994).…”

Alpine orogenic P‐T‐t‐deformation history of the Catena Costiera area and surrounding regions (Calabrian Arc, southern Italy): The nappe edifice of north Calabria revised with insights on the Tyrrhenian‐Apennine system formation

“…Radiometric ages concerning the Alpine overprint affecting the Calabride Complex units range between Cretaceous‐Paleocene (Rb/Sr method [ Borsi and Dubois , 1968; Del Moro et al , 2000]) and Eocene‐Oligocene (Rb/Sr method on biotite [ Schenk , 1980]; Rb/Sr method on white micas [ Bonardi et al , 1987]; 40 Ar/ 39 Ar method on biotite [ Rossetti et al , 2001]). In north Calabria, such age spanning is likely due to the fact that thermal conditions during Alpine metamorphism were too low (thermal peak < ∼300°C) to induce a complete reopening of the K‐Ar isotope system in micas from the Calabride Complex [ Rossetti et al , 2001].…”

Pressure–temperature evolution of the late Hercynian Calabria continental crust: compatibility with post‐collisional extensional tectonics

“…Alternatively, it has been proposed that isothermal exhumation and granitoids emplacement took place in a framework of post‐collisional extension (Caggianelli et al. , 2000; Del Moro et al. , 2000; Caggianelli and Prosser, 2002), similarly to the tectonic evolution of the French Massif Central and the Sardinia Massif to which the Hercynian Calabria region has been palaeogeographically related (Matte, 1986, 2001; Stampfli and Borel, 2002; Von Raumer et al.…”