1. Lake isotope records of the 8200-year cooling event in western Ireland: Comparison with model simulations
- Author
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Holmes, JA, Tindall, J, Roberts, N, Marshall, W, Marshall, JD, Bingham, A, Feeser, I, O'Connell, M, Atkinson, T, Jourdan, AL, March, A, and Fisher, EH
- Subjects
Global and Planetary Change ,8200-year event ,Geology ,stable-isotopes ,precipitation ,hydrological changes ,abrupt climate-change ,Early Holocene ,thermohaline circulation ,impact ,surface ,holocene ,Isotope-enabled GCM ,agassiz ,Ireland ,Ecology, Evolution, Behavior and Systematics ,bp cold event ,Oxygen-isotopes - Abstract
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.
- Published
- 2016