MIS 5e sea surface temperature estimation; a multi-proxy approach using a marine macrofossil assemblage (Mar Piccolo, Gulf of Taranto, Southern Italy)

Abstract

It is reported a multi-proxy palaeoclimatic study conducted on a MIS 5e calcarenite from the Mar Piccolo Basin (MP), Gulf of Taranto (GT) (Central Mediterranean). The calcarenite returned a rich malacofauna consisting of 120 extant species, including four of the tropical Senegalese Fauna, today absent in the Mediterranean. The biogeographic-climatic affinity of the assemblage shows, compared to today, a double percentage of warm affinity species, while the cold affinity species are nearly equally represented, indicating a warmer but not strictly tropical SST. This is confirmed by the most recurring preferred SST ranges of the assemblage, indicating an average of 20 °C. The skeletal compositions of five well-preserved molluscan and coral specimens were analyzed for trace elements and stable isotopes for further mean SST estimations. From the comparison of the results of several equations available in literature, it appears that only some SST estimations are realistic, converging into similar values of, on average, 20.8 ± 0.9 °C. Considering all the used proxies, the MIS 5e SST difference compared to today falls in the range 1.2–2.0 °C for the GT (being a more reasonable scenario) and 2.0–2.8 °C for the MP. This is not a firmly tropical-like SST setting as suggested by the sole Senegalese fauna, indicating at least 2.7 °C–3.5 °C more than today's GT and MP, respectively. The approximations and assumptions made for obtaining SST values with any single proxy indicate the need of a multi-proxy approach to define the best SST estimation.