Palaeotemperature estimation in the Holsteinian Interglacial (MIS 11) based on oxygen isotopes of aquatic gastropods from eastern Poland

Abstract

AbstractFor quantitative estimation of past water temperature of four Holsteinian (MIS 11) palaeolakes from eastern Poland, the oxygen isotope palaeothermometer was applied to shells of the aquatic gastropodsViviparus diluvianusandValvata piscinalis. The δ18O composition of their shells demonstrated the average growth-season water temperatures during the mesocratic stage of the interglacial (Ortel Królewski Lake), during its climatic optimum – theCarpinus–AbiesZone (Ossówka-Hrud, Roskosz and Szymanowo Lakes), and in the post-optimum (Szymanowo Lake). The calculation was based on δ18OShellvalues and the δ18OWaterassumed for the Holsteinian from the modern oxygen isotope composition of precipitation and the expected amount of evaporative enrichment. The mean oxygen isotope palaeotemperatures of Ortel Królewski lake waters were in the range of 18.1–21.9°C and were uniform for theTaxusandPinus–Larixzones. Ossówka-Hrud and Roskosz Lakes had mean temperatures of 17.4–21.0°C during the climatic optimum, whereas the temperature of Szymanowo lake waters was estimated at 20.6–21.7°C at that time. These values are concordant with the pollen-inferred July air temperatures noted during the Holsteinian in eastern Poland. Relatively high values of ~25°C in the post-optimum noted at Szymanowo were connected with the presence of a shallow and warm isolated bay indicated by pollen and mollusc records.