Lake isotope records of the 8200-year cooling event in western Ireland: comparison with model simulations

• Main Author: Holmes, JA
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: 8200-year event; Oxygen-isotopes; Isotope-enabled GCM; Early Holocene; Ireland; North Atlantic; Northeast Atlantic
• Online Access: https://discovery.ucl.ac.uk/id/eprint/1469763/8/1-s2.0-S0277379115300366-main.pdf; https://discovery.ucl.ac.uk/id/eprint/1469763/

The early Holocene cooling, which occurred around 8200 calendar years before present, was a prominent abrupt event around the north Atlantic region. Here, we investigate the timing, duration, magnitude and regional coherence of the event as expressed in carbonate oxygen-isotope records from three lakes on northwest Europe's Atlantic margin in western Ireland, namely Loch Avolla, Loch Gealáin and Lough Corrib. An abrupt negative oxygen-isotope excursion lasted about 200 years. Comparison of records from three sites suggests that the excursion was primarily the result of a reduction of the oxygen-isotope values of precipitation, which was likely caused by lowered air temperatures, possibly coupled with a change in atmospheric circulation. Comparison of records from two of the lakes (Loch Avolla and Loch Gealáin), which have differing bathymetries, further suggests a reduction in evaporative loss of lake water during the cooling episode. Comparison of climate model experiments with lake-sediment isotope data indicates that effective moisture may have increased along this part of the northeast Atlantic seaboard during the 8200-year climatic event, as lower evaporation compensated for reduced precipitation.