Changes in North Atlantic Radiocarbon Reservoir Ages during the Allerd and Younger Dryas

Marine samples yield higher 14C ages than terrestrial plants of the same age. This off-set is called the marine reservoir age and it has to be corrected for in order to correlate marine and terrestrial records of late Quaternary climate. The problem is made complicated by the reservoir age varying geographically and over time. We have determined the correction for the North Atlantic for a critical period with large and abrupt climatic changes at the end of the last ice age.

The method we used was to date marine shells and terrestrial plant remains deposited in two marine bays on Norway’s west coast between 11,000 and 14,000 years ago, a time of large and abrupt climatic changes that includes the Younger Dryas cold episode. The radiocarbon-age difference between the shells and the plants shows that reservoir ages increased from 400 to 600 years in the early Younger Dryas, stabilized for 900 years, and dropped by 300 years within a century across the YD-Holocene transition.

Reference:
Bondevik, Stein, Mangerud J., Birks H. H., Gulliksen S., Reimer P. (2006): ”Changes in North Atlantic radiocarbon reservoir ages during the Allerd and Younger Dryas”, in Science:
Vol. 312. no. 5779, pp. 1514 – 1517.