Provenence and paleogeographic evolution in a multi-source foreland: the Cenozoic Venetian Basin (NE Italy)

ABSTRACT: Diachronous deformation and exhumation of the Dinaric, eastern Southern Alps, and Northern Apennine belts
caused a complex pattern of sedimentation and dispersal in the Venetian–Friulian Basin. Our dataset provides, for the first
time, a comprehensive picture of the Cenozoic evolution across the whole basin. Growth and erosion of the three chains feeding
the Venetian–Friulian Basin are here traced by combination of multiple analytical techniques. We examine the terrigenous and
intrabasinal supply to the basin by using arenite petrography (gross composition, heavy minerals) and apatite fission-track
analysis framed in an updated stratigraphy. Data come from both outcropping and subsurface Eocene to Pleistocene strata and
are compared with the modern river sediments of the study area. On the basis of this approach, we present a schematic temporal
and paleogeographic evolution of the Venetian–Friulian Basin from the Eocene to Present.
During the Eocene most sediments were derived from erosion of carbonate successions within the growing Dinaric thrust belt
to the east, and from its peripheral bulge to the west, where some carbonate factories were active. Oceanic rocks, probably
located in the Vardar suture zone to the north, contributed little. Once Dinaric thrusting ceased, most of the detritus was
derived from the northern basement of the Austroalpine realm. An abrupt paleogeographic variation caused by activation of
southward-verging thrusts in the Southalpine domain occurred during the Serravallian. The drainage divide moved southward
and most of the detritus was derived from the basement and related sedimentary covers of the Southern Alps. Sand composition
of modern river sediments and of the Plio-Pleistocene deposits indicates that the modern hydrographic pattern of this area was
already established in the Pleistocene.