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

• Published in: Quaternary Science Reviews
• Main Authors: Holmes, JA, Tindall, J, Roberts, N, Marshall, W, Marshall, JD, Bingham, A, Feeser, I, O'Connell, M, Atkinson, T, Jourdan, AL, March, A, Fisher, EH
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2016
• Subjects: North Atlantic; Northeast Atlantic
• Online Access: https://eprints.whiterose.ac.uk/89398/; https://eprints.whiterose.ac.uk/89398/15/1-s2.0-S0277379115300366-main.pdf; https://doi.org/10.1016/j.quascirev.2015.06.027

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.