First record of Pliocene (Zanclean to mid Piacenzian) marine deposits on Rhodes (Greece): implications for eastern Mediterranean palaeo(bio)geography

Pliocene (Zanclean to mid Piacenzian) marine deposits from Cape Vigli on southwestern Rhodes (Mediterranean Sea, Dodecanes, Greece) are described, and assigned to the newly defined Cape Vigli Formation. Highly fossiliferous sandy to silty mudstones contain a diverse parautochthonous mollusc assemblage dominated by articulated specimens of the bivalves Pinna nobilis and Megaxinus ellipticus, and by abundant Persististrombus coronatus gastropods. These taxa formed part of a seagrass community. Combined with sedimentological evidence and microfossil assemblages (foraminifera, calcareous nannofossils), they indicate a very shallow (<5 m deep) depositional environment in a sheltered marine embayment close to the coast. The fossil community is characterised by the occurrence of several Late Miocene to Pliocene warm-water mollusc taxa, which had their acme in the Zanclean and have become extinct in the Mediterranean in the early Piacenzian. Consequently, these molluscs testify to a Zanclean to mid Piacenzian age. This assignment is corroborated by the calcareous nannofossil assemblages of the deposits, which support a potential latest Miocene (latest Messinian) to Early Pleistocene (early Gelasian) age (calcareous nannofossil zones NN12 to NN17). The occurrence of marine Pliocene deposits on Rhodes indicates that the depositional history of the island is more intricate than previously assumed. The shallow marine nature of the studied strata provides new evidence to reconstruct the position of the palaeo-coastline during Pliocene times, when Rhodes was still connected to Anatolia. So far, fossiliferous shallow marine strata of Zanclean to mid Piacenzian age in the eastern Mediterranean had been documented from Hatay Province (southern Turkey) and Agia Triada (southwestern Peloponnese, Greece). The newly discovered locality of Cape Vigli thus provides a significant, novel dataset, which helps to evaluate the palaeobiogeography of Pliocene biota.