Paleoenvironmental changes during MIS 1-5 in the Gulf of Corinth (eastern Mediterranean): IODP Expedition 381

Abundances and assemblage composition of benthic foraminiferal, dinoflagellate cysts and pollen were analysed together with sedimentological and geochemical proxies to investigate paleoenvironmental changes recorded in the Gulf of Corinth during MIS 1-5. The Gulf of Corinth is a relatively young (<5 Ma) and active continental rift zone in the eastern Mediterranean Sea, currently connected to the Ionian Sea through a shallow sill (60 m of depth) and to the Aegean Sea via the Corinth Canal (Isthmus; 6 km-wide). The coring sites of the IODP Expedition 381 are located in the central part of the gulf and the Alkyonides Gulf, a shallow semi-enclosed sub-basin within the northeastern part of the Gulf of Corinth. The closed drainage system and the high sedimentation rates make the study area ideal for investigating the complex interactions between sedimentary input, tectonics and climate through the basin’s evolution.

The benthic foraminiferal, dinocyst and pollen records are highly variable during both the Last Interglacial Complex and the Holocene. Mesotrophic to eutrophic marine conditions prevailed, as indicated by the high abundance of infaunal foraminiferal species (Bolivina spp., Melonis affinis, Bulimina spp., Cassidulina carinata, Valvulineria bradyana), with marine dinocysts (Nemaosphaeropsis labyrinthus, Spinifireties ramosus) and montane trees likely occurring during high sea-levels. During glacial and interstadial intervals, benthic foraminifers are mostly absent whereas abundant brackish dinocysts (Pyxidinopsis psilata) indicate a sea-level drop below sill level and the subsequent (semi-)isolation of the basin. Steppic pollen taxa predominate during the same intervals. Inorganic carbon content and elemental values varied following the inferred sea-level fluctuations, as well as the benthic foraminiferal oxygen isotope record which is discontinuous and conditionally limited to the presence of well-preserved benthic foraminifera. The beginning of the Holocene is marked by the re-establishment of marine conditions as the sea-level rose above the sill and the basin re-connected with the Mediterranean Sea.

This study is funded through projects GR 5285/3-1 “Late Quaternary dynamics of marine paleoenvironments and ecosystems in the Gulf of Corinth (eastern Mediterranean)” and PA 2664/8-1 “Linking marine and terrestrial ecosystem responses to climate variability since the Last interglacial in the Eastern Mediterranean” of the Deutsche Forschungsgemeinschaft (DFG).