The Calabrian Orocline: buckling of a previously more linear orogen

Abstract

AbstractRecent structural studies of the Apennines and the Calabrian orocline and a compilation of structural, stratigraphic, GPS and palaeomagnetic data from the central and western Mediterranean region show that beginning in the Late Miocene a N–S trending ribbon continent that had been previously deformed, and which we now recognize as the Apennine–Sicilian thrust belt, buckled eastward in response to northward movement of Africa relative to stable Europe. A simple geometric model is consistent with available data and shows how eastward buckling of an originally north–south continental beam explains: (1) opening of the Tyrrhenian Sea basin from 7–2 Ma, at which point sea-floor spreading ceases and the basin begins to shrink by southward subduction beneath Sicily; (2) the coeval development of an east-verging fold-and-thrust belt along the length of the Apennine–Sicilian belt in response to overthrusting of the autochthon to the east, followed by extension beginning at 1 Ma as the Apennine portion of the beam begins to retreat to the SW; and (3) subduction of continental and oceanic lithosphere east of the buckling beam into a trench that migrates eastward through time due to ‘push back’ by the buckling upper plate.