THE LAST GLACIAL-INTERGLACIAL (LGIT) CHANGE IN IRELAND: NEW EVIDENCE FROM COLEOPTERAN RECORDS

The LGIT was a period characterised by several rapid, extreme shifts in climate across the North Atlantic region. Lowe et al (1999) rightly point out problems associated with identifying the synchroneity of events and the important role of quantified climate proxies in determining the magnitude of climate shifts. For instance, using quantified temperature reconstructions of the mean warmest month (TMAX) from Coleopteran assemblages, Coope et al (1998) reported significant differences in the overall trend and timing of temperature variations across northern Europe during the LGIT. Significantly, though, there was little representation from Ireland, at the extreme western end of the transect.

Ireland’s contribution to this debate has not been fully realised, despite being uniquely placed to record changes in the location of the Polar Front and associated changes in climate on the most western extreme of a transect across northern Europe. The prevailing westerly airflow combined with the strongly controlled maritime climate and an absence of any significant ice cap at the time of the LGIT allow climatic changes to be identified and quantified free from any effects of ice and continentality in the east. The LGIT is well documented, with numerous high-resolution deposits of suitable age and an established tephrostratigraphic record for the Holocene, suggesting the good potential for a late glacial tephra chronology.

We present results from recent investigations of Irish late glacial deposits and a new, Coleopteran-inferred temperature curve for Ireland. We focus on the findings from a high-resolution site on the east coast, Roddans Port, Co. Down. The tephrostratigraphic record for the site is being presented separately. We compare the results from this site with other Irish investigations being carried out at Ballybetagh Bog (Co. Wicklow) and Craddenstown (Co. Louth), and with other proxies. Finally, we discuss the significance of this work within the wider context of the North Atlantic region.

References Coope, G.R. et al. 1998. Journal of Quaternary Science 13 (5), 419-433 Lowe, J.J. et al. 1999. Journal of the Geological Society, London, 156, 397-410.