GEOG 205 Lecture Notes - Younger Dryas, Till, Radiocarbon Dating
Document Summary
February 18th, 2013: rapid climate change, the younger dryas. Not all climate change is gradual & slow. Younger dryas: short duration cold event (stadial) first recognized from evidence in nw europe. After last glacial maximum, ice sheets begun to retreat & climate warming. Pollen in cores from lakes/bogs in europe provide evidence of changes in vegetation that reflect warming in climate 18 000 years ago. But, found pollen from dryas octopetela 11 000 years ago from the tundra that pointed to abrupt cooling in western europe. 1975 bob mott reported similar abrupt cooling in new brunswick & nova scotia. Evidence shown through lake sediments on glacial tills covered by peat/soil that were thin & covered by second till with little organic matter. Alpine swamp, nj showed no evidence of younger dryas: c-14 dating shows very small amounts (single seed, a needle, palynology used: study of pollen & spores.
