The Derryvree Freshwater Pause
MIS 3 extended broadly from about 57,000 to 29,000 years ago. It was not uniformly frozen. Greenland ice-core records show repeated abrupt shifts between colder stadials and relatively milder interstadials, while the British–Irish Ice Sheet changed in extent and form. At around 32,800 calibrated years before present, the island lay before the fullest later expansion of the last ice sheet, but that does not mean that Ireland was simply ice-free. Conditions varied greatly by region, altitude and time. Some places may have been affected by glacier ice; elsewhere, exposed ground, lakes, streams and wetlands could persist for intervals.