Terrestrial climate signal of the “8200 yr B.P. cold event” in the Labrador Sea region
- Timothy J. Daley1,2,*,
- F. Alayne Street-Perrott1,
- Neil J. Loader1,
- Keith E. Barber2,
- Paul D.M. Hughes2,
- Elizabeth H. Fisher3 and
- James D. Marshall3
- 1School of the Environment and Society, Swansea University, Swansea SA2 8PP, UK
- 2Palaeoecology Laboratory (PLUS), School of Geography, University of Southampton, Southampton SO17 1BJ, UK
- 3Department of Earth and Ocean Sciences, University of Liverpool, Liverpool L69 3GP, UK
- *E-mail: t.j.daley{at}swansea.ac.uk.
Abstract
Accelerated melting of Greenland ice has raised concern about the future impact of enhanced freshwater discharge on regional climate through its effect on ocean circulation. An abrupt cooling event ca. 8200 cal. yr B.P. has been linked to meltwater from the decaying North American ice sheet. Oxygen isotopic analyses of cellulose from subfossil Sphagnum mosses, isolated from a Newfoundland peat core, reveal a pronounced anomaly ca. 8350 yr B.P. with a duration of ~150 years. The maximum estimated δ18Oprecipitation change, 4.53‰ ± 1.05‰ (Vienna Standard Mean Ocean Water), is the largest observed in the circum-North Atlantic region. The magnitude of change exceeds that predicted by recent paleoclimate simulations. Comparisons with recent records of surface and deep ocean proxies in the Labrador Sea and the wider North Atlantic region suggest synchroneity. However, an ~200 year delay between the responses of the Labrador Sea region and the Greenland Ice Sheet to the effects of meltwater release remains to be explained.
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- Received 20 January 2009.
- Revision received 15 April 2009.
- Accepted 28 April 2009.
