The late Pliocene-Pleistocene transition in North-Eastern Tunisia (Cap Bon Peninsula) as example from the western Mediterranean basins: Paleontological, taphonomical and paleoecological data

Abstract

Northeastern Tunisia, is part of the Western edge of the Pelagian Mediterranean basins. During the Neogene, it formed a tip of a large embayment where marine, and paralic systems prevailed. The biodiversity analysis of the Piacenzian (MPL 5a) and Gelasian (MPL5b and MPL6) reveals highly fossiliferous content (ostracods, planktonic foraminifers and oysters). Four oyster species are identified, including Neopycnodonte cochlear and Hyotissa hyotis, newly characterized in the Lobna section. Encrustations on oysters are primarily barnacles, vermetids, bryozoans and juvenile oysters. Facies analysis, taphonomy and ichnology indicate a shift from a quiet offshore muddy environment during Late Pliocene (Top of Sidi Barka Formation = SBF) to a moderate-high energy inner sandy shelf setting in the Early Pleistocene (Hammamet Sandstones Formation = HSF) resulting from the interplay between global sea-level fall, regional cooling and local tectonics related to the alpine phase. The foraminifera and ostracod biostratigraphic revisions, together with the Carbon, Oxygen isotopic composition of the oyster shells show that a major change coincides with the Pliocene-Pleistocene boundary, making the Cap Bon a particularly interesting succession in the local series boundary stratotype.