From present rivers to old terrigenous sediments: the evolution of the drainage system in the eastern Southern Alps

The eastern Southern Alps are presently dominated by southward drainage systems feeding the Venetian–Friulian plain confined to the south of the Insubric Lineament. Following the assumption that river sediments reflect, in the first instance, the rocks outcropping in their catchments, the comparison between present fluvial and old terrigenous sediments lets us to evaluate changes in provenance since the late Miocene, when the basement exhumation along the Valsugana Thrust system took place as indicated by apatite fission-track data. This tectonic event determined the onset of the main drainage systems the evolution of which has been depicted tracking the petrographic signatures from the Present back to the late Miocene. Provenance data show important episodes of stream piracy and watershed migration, in response to tectonic uplift in the Southern Alps, as well as to the Messinian Salinity Crisis and the Quaternary glaciations.