Seasonal climate variations during Marine Isotope Stages 3 and 2 inferred from high-resolution oxygen isotope ratios in horse tooth enamel from Lower Austria

Abstract

We present sequential oxygen isotope records (δ¹⁸O_phosphate vs. VSMOW) of horse tooth enamel phosphate of six individuals from two adjacent Palaeolithic sites in Lower Austria. Three molars from the site Krems-Wachtberg date to 33–31k cal a bp, and three molars from Kammern-Grubgraben to 24–20k cal a bp. All teeth show seasonal isotope variations, which are used to reconstruct the annual oxygen isotope composition of drinking water (δ¹⁸O_dw) and palaeotemperatures. Measured δ¹⁸O_phosphate values ranged from 8.6 to 13.0‰ and from 10.8 to 13.9‰ at Krems-Wachtberg and Kammern-Grubgraben, respectively. An inverse modelling approach was used to reconstruct summer and winter temperatures after a correction for glacial oceanic source water δ¹⁸O. Reconstructed annual δ¹⁸O_dw was −16.4 ± 1.5‰ at Krems-Wachtberg and −15.3 ± 1.4‰ at Kammern-Grubgraben, resulting in annual temperatures of −5.7 ± 3.1 and −3.5 ± 2.9°C, respectively. Summer and winter temperatures reconstructed from individual teeth exhibit high seasonal variations with moderate summer temperatures and extremely low winter temperatures typical for a polar tundra climate. Isotopic differences between individuals are attributed to interannual climate variability or to different drinking water sources. Our reconstructed temperatures are, overall, consistent with previously reported values from European horse teeth, when taking regional differences into account.