Deglaciation of the Burren glacio‐karst, western Ireland, during Termination 1: Implications for North Atlantic climate and karstification

Abstract

The Burren uplands in western Ireland form one of the most extensive and best‐preserved examples of glacio‐karst in Europe. Subsumed by the Irish ice sheet during the Late Pleistocene, granite erratic boulders and in situ silica veins in the limestone bedrock provide a rare opportunity to reconstruct the timing and rate of deglaciation following the Last Glacial Maximum (LGM) using cosmogenic beryllium‐10 ( 10 Be) surface‐exposure dating. Such information is key to establishing seasonal climatic conditions in the circum‐North Atlantic during the last glacial termination, particularly Heinrich Stadial 1 (HS1: ~18.0–14.7 ka), and quantifying landscape denudation rates in temperate maritime karst systems. This study reports a new deglacial chronology from the Burren, constrained with in situ 10 Be and supported by minimum‐limiting U‐Th and 14 C ages, that reveals pronounced thinning and retreat of terrestrial ice between ~18.0 and 17.0 ka. In conjunction with existing measurements of Burren karst features, we applied the new age constraint for postglacial exposure to refine long‐term denudation rates, which are broadly similar to other maritime European karstlands. The close agreement between the 10 Be surface‐exposure ages and independent ages for Burren deglaciation also permits an empirical test of our chosen production rate and confirms it is applicable to this period and these latitudes. From a palaeoclimatological perspective, the Burren 10 Be record indicates deglaciation during HS1, a pattern that we propose supports recent hypotheses invoking globally warming Heinrich summers despite anomalous wintertime cooling of the circum North Atlantic.

Bibliographic Information