Stable carbon and oxygen isotope compositions of invertebrate carbonate shells and the reconstruction of paleotemperatures and paleosalinities—A case study of the early Pleistocene of Rhodes, Greece

The coastal sediments of Rhodes in the eastern Mediterranean have recorded transgression–regression cycles that took place during the early Pleistocene. The sedimentary deposits from the Kritika Member of the Rhodes Formation consist in conglomerates, sandstones, siltstones and clays deposited in brackish to shallow marine environments. Faunal associations are dominated by molluscs and reveal rapid ecological changes. Carbon and oxygen isotope ratios of aquatic skeletal carbonates show that these ecological changes were most likely driven by large salinity changes while water temperature remained rather constant at about 22.0 ± 1.5 °C. The tectonic activity of the island rather than glacio-eustatic variations of climatic origin is advocated to be responsible for the ecological and salinity changes and sea-level variations recorded in the sedimentary sequence.

► Pleistocene sediments of Rhodes recorded rapid changes in mollusc assemblages.
► δ13C and δ18O of molluscs show that ecological changes were driven by salinity.
► Mean water temperature recorded by Glycymeris was 22.0 ± 1.5 °C.
► Climatic conditions reflect an interglacial phase.
► Tectonic activity triggered ecological and salinity changes.