Palynological and oxygen isotope investigations on Late‐Glacial sediment cores from Swiss lakes

Abstract

Results from detailed pollen and 18 O/ 16 O studies on two sediment profiles from small Swiss lakes are reported. 18 O/ 16 O records in lacustrine carbonate contain paleoclimatic information because they reflect mainly the isotope ratio in rain and snow which is correlated to temperature. Several transitions between different climatic periods determined palyno‐logically are also indicated by marked changes in the isotope ratios in both profiles, namely the transitions Oldest Dryas ‐ Bøiling and Allerød ‐ Younger Dryas ‐ Preboreal. 18 o/ 16 O was 2 to 3 %0 lower during Younger Dryas than during the adjacent periods, corresponding to a temperature drop of a few degrees Centigrade according to a tentative estimate.