Marta Marchegiano, Marion Yolande Peral, Jeroen Venderickx, Koen Martens, Antonio García-Alix, Christophe Snoeck, Steven Goderis, Philippe Claeys 

This study presents the ostracod clumped-isotope (∆47) thermometer, a new tool that provides quantitative temperature and hydrological reconstruction from lacustrine systems, which are among the best archives to reconstruct continental paleotemperature variations. The relationship between ∆47 and the temperature at which ostracod shell crystallized, is determined by measuring ∆47 on different species grown under controlled temperatures in both natural environments (4 ± 2°C; 12 ± 1°C) and lab cultures (23 ± 0.5°C). No consistent offset between the two species originating from the same environment and precipitated at the same temperature is reported, suggesting the absence of a vital effect in ostracod ∆47. In addition, the excellent agreement between the presented ostracod data and the carbonate clumped-isotope unified calibration (Anderson et al., 2021) suggests that the use of the latter can be extent to continental biogenic carbonates that do not present a kinetic effect. The ostracod-∆47 thermometer constitutes a reliable tool for continental palaeoclimate reconstructions that can be widely used in freshwater systems in all climatic belts.