Miocene progressive forearc extension in the Central Mediterranean

Miocene extensional sedimentary basins are being increasingly recognized in Central Mediterranean. However the paleogeographicreconstruction of the Paleo-Tyrrhenian during this time span results a difficult task because the subsequentPliocene-Quaternary backarc opening moved away these older sedimentary basins. Our study outlines principal deformationevents recorded by sediments that were deposited within minor basins of the Tyrrhenian Sea region and providesconstraints on the duration of these events.The interpretation of seismic profiles, wells, and outcrops data together with a review of the middle-upper Miocenesuccessions permitted us to recognize Miocene third order depositional sequences, reconstruct the fault pattern, and furnisha detailed evolution of the sedimentary basins that preceded the Pliocene-Quaternary Tyrrhenian high stretching.Based on the stratigraphic and tectonic constraints together with the age migration of the depocenters, we reconstructeda detailed paleogeographic evolution of central Mediterranean. Sedimentary basins architecture and fault pattern indicatea system of approximately N-S oriented normal faults and approximately E-W transform faults that were active sincethe Late Oligocene. Two period of extensional/transtensional tectonics (late Oligocene-Lower Burdigalian and UpperLanghian-Tortonian) were interrupted by a compressional event (late Burdigalian-Lower Langhian).Tacking in account the position of the Miocene volcanic arc (Sardinia), we propose that the coeval sedimentary basinsdeveloped in the central Mediterranean as forearc extensional/transtensional basins during the progressive collision withthe African plate and before the Tyrrhenian backarc opening. Unlike published late Oligocene-Tortonian reconstructionsof the western-central Mediterranean realm that report a linear migration of backarc extension, our results support a geodynamicmodel characterized by a progressive deformation of the forearc extension in the overriding plate.