Vertebrate-fossil rich plattenkalk of Pietraroia (Southern Appennines, Italy). Evidence for submarine channel depositional setting

Pietraroia plattenkalk are richly fossiliferous, fine-grained cherty limestones, from the Matese Mountains - Southern Apennines, Italy, and are well known for the exceptional state of preservation of the fossils. Based on detailed thaphonomical analises, fossil assemblage recognised in the Pietraroia plattenkalk represents a taphocoenosis and an obruption deposit in the sense that most (if not all) of the animals were transported to an accumulation site from other places. A likely scenario could be represented by a depressed area in which gravitative currents carrying animals from above, capturing both the alive and the dead, deposited them into accumulation sites placed well below the original place where they lived and/or died.The Pietraroia plattenkalk sequences, on the basis of sedimentological analises and geometrical reconstructions, are here interpreted as abandon deposits of a submarine channel “Pietraroia Channel” documenting a major transgressive event. Transgression was associated with the development of suboxic to anoxic conditions at the sea-floor which favoured the preservation of fossils as well as the deposition of coprolith-rich and bituminous layers found within the plattenkalk sequences.A peculiar paleogeographic and paleotopographic setting, strongly controlled by local tectonic, saw the contiguity of wide emerged areas with a relatively deep-water channelised area where fossiliferous plattenkalk sequences were deposited.