EVIDENCE FOR ABRUPT CLIMATIC-CHANGE IN NO RTHERN SCOTLAND BETWEEN 3900 AND 3500 CALENDAR YEARS BP

Palaeohydrological and palaeoecological investigations from five locat ions in northern Scotland reveal a distinct and large-scale shift to w etter climatic conditions which may reflect a major transition in clim ate from the mid-to late Holocene. Radiocarbon age estimates place thi s transition between about 3900 and 3500 cal. BP, although the transit ion appears to have occurred abruptly, possibly over a decadal to cent ury timescale. This event appears to be synchronous with changes infer red for other regions, suggesting that it reflects a continental-scale , or possibly even global-scale, change in climate. Broad correlation with deep-sea sediment records suggests that the transition may reflec t colder sea-surface temperatures in the North Atlantic Ocean.