Dr. Peteet's Younger Dryas Images

(click on photos to enlarge)

Dryas octopetala is a flower in the Rosaceae family, typical of cold, open, Arctic environments. In the nineteenth century, the leaves and fruits of this plant were found in Scandinavia layers atop tree macrofossils, indicating that an abrupt climate shift to cold conditions took place. The shift was termed the Younger Dryas, as it was the youngest shift to cold conditions, and the most pronounced all over Europe. (see Abrupt Climate Change volume)

Kodiak Island coastal lake section showing changes from cold Younger Dryas conditions (with white ash layer running through grey clay layer) to brown organic layers indicative of the Holocene warm conditions, starting about 11,500 years ago. (Peteet and Mann, 1994)

Mesa, Alaska archeological site microblade. This is the earliest human occupation of North America and during the Younger Dryas, the Mesa site was abandoned as cold, drier conditions ensued. The beginning of the Holocene brought with it human presence at the site. (Mann et al., 2003).

Global distribution of cold conditions associated with Younger Dryas, as evidenced by ice cores, pollen records, lake level shifts, plant macrofossils, oxygen isotopes, and sediment color changes. (Peteet, in review)