From collisional to rifted basins: An example from the southern calabrian arc (italy)

Structural interpretation of available geological and geophysical data carried out along a regional transect extending across the southern Calabrian arc from the Tyrrhenian margins to the Ionian off-shore, demonstrates that a complex interplay between compressional and extensional processes has controlled the evolution of Upper Miocene-Pleistocene sedimentary basins developing in this region. Our data indicate that an Upper Miocene-Lower Pliocene succession outcropping in the southern Calabrian arc represents the infilling of perched basins developed between crystalline basement thrust sheets. A similar tectonic pattern characterises the Plio-Pleistocene basins occurring on the frontal part of the arc in the Ionian off-shore. Upper Pliocene-Pleistocene sediments outcropping along the Tyrrhenian side of the arc reveal that they in fact represent the infilling of extension-related basins. Time-space migration of compressional- and extensional-related sedimentary basins can be explained as the result of different tectonic processes developing on the upper plate as a result of the underplating of the Ionian domain beneath the Calabrian block. In this framework Upper Miocene-Lower Pliocene and Upper Pliocene-Pleistocene perched basins represent, therefore, fore-arc basins developed on the frontal accretionary wedge and/or on the hangingwall buttress of the arc during its southeastwards migration. Late Pliocene-Early Pleistocene extensional tectonics occurring along the Tyrrhenian side of the arc, may indeed be related to accommodation processes which characterised the rear of the wedge to maintain a stable geometry as a result of the underplating of the Ionian crust.