Figure 3.

Gerzensee (603 m above sea level) and Leysin (1,230 m above sea level), Switzerland. (A) The δ¹⁸O records of the lake marls and their correlation to the GRIP ice core chronology. (B) The sample scores on principal components analysis axis 1 of the biostratigraphies of pollen, Cladocera, and Chironomidae summarize the amount of compositional change between adjacent samples (2). Principal components analyses were run on four time windows separately (four symbols), such that the series scores depend on the core sections used and therefore do not exactly match at the overlaps. LST, Laachersee tephra.