A composite Pliocene record of sea surface temperature in the central Mediterranean (Capo Rossello composite section – South Sicily)

Abstract

The Pliocene (5.33–2.58 Ma) was the last period in the Earth's history when atmospheric CO2 concentrations were similar to today (~400 ppm) and global mean temperatures were significantly warmer. In the Mediterranean, the Pliocene, and more particularly the Piacenzian (3.6–2.58 Ma), has been intensively studied but less is known about the Early Pliocene climate. This study aims at filling this gap with a high-resolution alkenone-derived sea surface temperature (SST) record of the Zanclean epoch obtained from the composite Capo Rossello section (South Sicily). This new dataset is combined with the previously published records of Beltran et al. (2011), Herbert et al. (2015) and Herbert et al. (2018), to document SST changes during major regional and global oceanographic re-organizations such as the connection with the Atlantic basin. Our SST record highlights the key transition between the warm and unstable conditions during the Zanclean and the more stable and cooler Piacenzian, around 3.8 Ma ago. We suggest that this transition results from the intensification of the Mediterranean outflow and the establishment of the Northern Hemisphere glaciation. The combined effect of these mechanisms would be responsible for cooler, more seasonal and possibly dryer conditions in the Mediterranean.