The Late Glacial and The Younger Dryas-Preboreal boundary

As many of my colleagues know I love this picture of a Late Glacial sequence,

dug out by Hartmut Usinger, in Schleswig-Holsten. In the bottom we possibly have

something we could call Oldest Dryas (GS-2), followed by the dark so-called Bølling-

Allerød complex (GI-1e-1a). On top of that one sees an impressive Younger Dryas bed

(GS-1). The Holocene is of course at the top, but note the occurrence of a light layer 5 cm

above the YD/PB boundary, which may be the so-called Preboreal oscillation (PBO). Also note

the distinct, but not erosive boundaries. Isn´t that a beauty??!!

Dryas octopetala, the small but beautiful plant which, through the abundance of its resistant leaves in

European late-glacial deposits, named the cold periods of the Late Glacial in the pioneer works

of Scandinavian Quaternary geologists.