The Younger Dryas
was a sudden cold climate
period lasting for
about 1100-1300 calendar years during the final deglaciation of the
. It interrupted the warm interval of the Allerød
period and was followed by the Preboreal period
of the Holocene
. The Younger Dryas ended around 9600 BC (11550 calendar
years BP, occurring at 10000 radiocarbon years BP, a "radiocarbon
The prevailing theory holds that the Younger Dryas was caused by the
shutdown of the Gulf Stream in response to a sudden influx of
fresh water from deglaciation in North America. The global
climate would then have become locked into the new state until
freezing removed the fresh water "lid" from the north Atlantic Ocean.
Although the Younger Dryas had the greatest effect in Europe,
it was noted throughout the world including:
- Replacement of forest in Scandinavia with glacial tundra (which is the habitat of the dryas plant).
- Glaciation or increased snow in mountain ranges around the world.
- More dust in the atmosphere, originating from deserts in Asia.
- Drought in the Levant, perhaps motivating the Natufian culture to invent agriculture.
The end of the Younger Dryas was very sudden and it has been dated by
a variety of methods, with mostly consistent results:
References and external links
- 11530±50 BP -- GRIP ice core, Greenland 
- 11530+40-60 BP -- Kråkenes Lake, western Norway. 
- 11570 BP -- Cariaco Basin core, Venezuela 
- 11570 BP -- German oak/ pine dendrochronology 
- 11640±280 BP -- GISP2 ice core, Greenland 
- Spurk et al, Radiocarbon, 40, 1107-1116 (1998)
- Gulliksen et. al., The Holocene 8, 3 (1998)
- Hughen et. al., Science v.290 (2000) -- http://www.ngdc.noaa.gov/paleo/pubs/hughen2000/hughen2000.html
- Alley et al (1993)