Planktonic foraminifera and climate signals in the Gelasian stratotype section (Monte San Nicola, Sicily) at the Pliocene-Pleistocene transition

Abstract

A high-resolution analysis of planktonic foraminifera assemblages at the Monte San Nicola GSSP section (Southern Sicily), the type-section for the Lower Pleistocene Gelasian Stage, has been performed. The results on the assemblages are discussed in detail from MIS G4 to the onset of MIS 99 (between ∼2.7 and 2.5 Ma) and are integrated with previously published records of stable oxygen isotopes, alkenones, calcareous nannofossils and geochemistry from the same section. The main findings suggest that: i) planktonic foraminifera primarily responded to variations in surface water temperatures and nutricline depth, modulated by obliquity and summer insolation forcing; ii) the water column dynamics were influenced by both low- and high-latitude climate variability, capturing seasonal climate signals; iii) MIS 104 is confirmed to register the first appearance of a strong glacial signal in the Mediterranean during the Pliocene-Pleistocene transition; and iv) following MIS 104, enhanced seasonality in the marine environment was established, driven by a decrease in winter temperatures consistent with climate changes observed at mid-latitudes in the North Atlantic.