FISSION-TRACK ANALYSIS OF THE CRYSTALLINE BASEMENT ROCKS OF THE CALABRIAN ARC, SOUTHERN ITALY - EVIDENCE OF OLIGOMIOCENE LATE-OROGENIC EXTENSION AND EROSION

Fission track analysis is used to provide low temperature and time con straints on the late-orogenic cooling and exhumational history of the crystalline basement rocks of the Calabrian Are, southern Italy. 65 sa mples yielded 57 apatite fission track ages, 54 zircon fission track a ges and 25 apatite-confined fission track length distributions. Interp retation of this data reveals a phase of increased cooling rates relat ed to exhumation between approximately 35 Ma (mid-Oligocene) and 15 Ma (Middle Miocene). Evidence from the sedimentary record indicates sign ificant Oligo-Miocene erosion related to this period of exhumation. Ne w chronological constraints are also applied to localised late-orogeni c extensional tectonism that has recently been identified within the b asement rocks of the Calabrian Arc. This information is used to produc e a new model of the Oligo-Miocene tectonic evolution of the Calabrian Arc. It proposes that the crystalline basement rocks were part of a c ritical orogenic wedge between the mid-Oligocene and the Middle Miocen e.