Late Cretaceous Carbonate Turbidites of the Northern Apennines: Shaking Adria at the Onset of the Alpine Collision

ABSTRACT Thick and regionally widespread deepwater carbonate turbidite successions, the Upper Cretaceous Helminthoid Flysch, were deposited during the initial stages of Alpine collision. Despite the dominant intrabasinal origin, bulk composition and heavy minerals of minor terrigenous mode indicate provenance from different crustal levels of the European and Adria plates. These data allow us to place the Helminthoid Flysch units within a Late Cretaceous paleogeographic reconstruction of the Northern Apennine Tethys. The depositional characters of these turbidites indicate the coexistence of an active tectonic setting, a paleogeographic location prone to carbonate ooze production and storage, and limited terrigenous sources outside the basin.