Dating the topography through thermochronology: application of Pecube code to inverted vertical profile in the eastern Sila Massif, southern Italy

Valerio Olivetti (1,2), Maria Laura Balestrieri (3), Claudio Faccenna (1) & Fin M. Stuart (4)
(1) Università di Roma Tre, Dip. Scienze, L.go S. L. Murialdo, 00146, Roma, Italy.
Corresponding author-email: valerio.olivetti@uniroma3.it.
(2) Aix-Marseille Université (AMU), IRD, CNRS, CEREGE UM34, BP 80, 13545 Aix-en-Provence Cedex 4, France.
(3) CNR, Istituto di Geoscienze e Georisorse, U.O.S. Firenze, via La Pira 4, 50121 Florence, Italy.
(4) Isotope Geoscience Unit, Scottish Universities Environmental Research Centre, East Kilbride G75 0QF, UK, tel: 33 6 74888693.

The Sila Massif is a small part of an orogenic wedge that sits on top of the narrow and active Calabrian subduction zone. The topography of the Sila Massif is characterized by a plateau region whose age and origin has been long debated. Here we integrate new apatite (U-Th)/He data from the eastern flank of the massif with existing apatite fission-track (AFT) data, to constrain the topographic evolution of the massif. The new AHe ages range from 9.7 Ma to 49.8 Ma and overlap the AFT ages indicating that a phase of rapid Cenozoic exhumation was followed by an abrupt decrease of the exhumation rate. A steep/inverse AFT age-elevation relationship from a vertical profile on top of the summit area of the north-eastern Sila may records post-exhumation relief degradation, which is consistent with the low-relief upland topography. To test this hypothesis we performed inverse numerical modeling using Pecube code. Integrating the new AHe ages and the numerical modelling results with the geological constraints we propose a new model for the regional topographic evolution from 30 Ma to the present.

(U-Th)/He thermochronology, Calabrian Arc, Pecube, Topography evolution.