Chironomid‐inferred summer temperatures for the Last Glacial–Interglacial Transition from a lake sediment sequence in Muir Park Reservoir, west‐central Scotland. (April 2016) - Brooks, Stephen J.
ABSTRACT: Lake sediments spanning the Last Glacial–Interglacial Transition (LGIT: ca. 14.7 to 8 ka BP) from Muir Park Reservoir (MPR) in west‐central Scotland were analysed for chironomids. The site lies just outside the southern limit of a former glacier that advanced into the Loch Lomond Basin during the Loch Lomond (Younger Dryas) Stadial. Chironomid‐inferred mean July temperatures were derived using a modern Norwegian calibration dataset. Three tephra layers constrain the sequence chronologically. Inferred temperatures decline from a high value early in the Interstadial, punctuated by two cold oscillations, probably equivalent to GI‐1d and GI‐1b in the Greenland ice‐core record, and a warm oscillation (equivalent to GI‐1a) immediately before the severe cooling at the start of the Loch Lomond Stadial (GS‐1), when summer temperatures fell by about 5 °C below the Interstadial average. Summer temperatures fell by about 3 °C below the Interstadial average during GI‐1d, which is less severe than inferred from other chironomid records from eastern Scotland, and may reflect the influence of an oceanic–continental gradient. Cooling during GI‐1b was particularly strong at MPR when minimum temperatures were about the same as those reached during GI‐1d, unlike other sites investigated where GI‐1d is usually between 1 and 2 °C cooler than GI‐1b.