Stratigraphic frame work of the type locality of Pirro Nord Mammal Faunal Unit (Late Villafranchian, Apricena south-eastern Italy)

The fossiliferous karst deposits of the typical Pirro Nord Faunal Unit recently revived interest for the lithic tools documenting the human occurrence in southern Italy at Early Pleistocene. Therefore, a revision of the Pliocene to lowermost Pleistocene stratigraphic succession was needed. It was carried on with a twofold aim: to detail the stratigraphic architecture and the structural-depositional evolution of the “Apricena horst”, and to verify the chronostratigraphic constraints for the Pirro Nord F.U. in the type area of Apricena. The stratigraphic record has been subdivided in four units bounded by ubiquitous unconformity surfaces, often associated to evidence of sub-aerial exposure. Facies changes and unconformity surfaces reflect the activity of the E-W trending normal faults bounding the study area which, since the late Early Pliocene, was a submerged horst characterized by highly variable sedimentation rates, repeated episodes of no-sediment supply and a significant synsedimentary seismic activity. The southern fault of the Apricena horst. Assumes particular significance because the karstification preferentially developed along the fractured fault core-zone; the resulting hypogeous features were filled up by sediments bearing late Villafranchia biogenic remains whose age is confirmed within the Early Pleistocene (sensu pre-IUGS reccomandation). At present no more precise age information is available, except for the one derived from biochronological data based on the vole Allophaiomys ruffoi.