HR: 1340h
AN: PP33B-1561    [Abstracts]
TI: Problems With Identifying the `8,200 Year Event' in Terrestrial Records of the Atlantic Seaboard: a Case Study From Dooagh, Achill Island, Ireland.
AU: Head, K S
EM: katiehead@slemishmtn.co.uk
AF: The Queen's University of Belfast, School of Archaeology and Palaeoecology, 42 Fitzwilliam Street , Belfast, BT7 1NN United Kingdom
AU: * Turney, C S
EM: turney@uow.edu.au
AF: The Queen's University of Belfast, School of Archaeology and Palaeoecology, 42 Fitzwilliam Street , Belfast, BT7 1NN United Kingdom
AU: * Turney, C S
EM: turney@uow.edu.au
AF: University of Wollongong, School of Earth and Environmental Sciences, Wollongong, NSW 2522 Australia
AU: Pilcher, J R
EM: j.pilcher@qub.ac.uk
AF: The Queen's University of Belfast, School of Archaeology and Palaeoecology, 42 Fitzwilliam Street , Belfast, BT7 1NN United Kingdom
AU: Palmer, J G
PP33B-1561 AF: The Queen's University of Belfast, School of Archaeology and Palaeoecology, 42 Fitzwilliam Street , Belfast, BT7 1NN United Kingdom
AU: Baillie, M G
EM: m.baillie@qub.ac.uk
AF: The Queen's University of Belfast, School of Archaeology and Palaeoecology, 42 Fitzwilliam Street , Belfast, BT7 1NN United Kingdom
AB: The Northern Hemisphere 8200 year cooling event is believed to represent the last known major freshwater pulse into the North Atlantic as a result of the final collapse of the North American Laurentide ice sheet. This pulse of water is generally believed to have occurred independent of orbital variations and provides an analogue for predicted increases in high-latitude precipitation and ice melt as a result of anthropogenically-driven future climate change. The precise timing, duration and magnitude of this event, however, is uncertain within the context of Ireland. Here, we investigated a high-resolution peat sequence at Dooagh, Achill Island on the west coast of Ireland to investigate whether the 8200 year event impacted on the terrestrial vegetation. We find clear evidence for an oscillation in the early Holocene using various measures of pollen, indicating a disruption to the vegetation with a sustained shift to open grassland, most probably driven largely by changes in precipitation rather than temperature. Radiocarbon dating of the event was extremely problematic, however, with bulk peat samples systematically too young suggesting significant contamination, potentially from percolating humic acids subsequent to the event. These results have major implications for high-precision dating of sequences in high rainfall areas. Nevertheless, assuming the oscillation in Dooagh is the 8200 year event, the sustained disruption to vegetation was of the order of hundreds of years, and not tens of years as suggested recently for the west coast of Ireland.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1640 Remote sensing (1855)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005