Fermanagh’s Silt Interval
Ireland was not then the familiar green, wooded island of later prehistory. Its climate was cold, but not simply and permanently frozen. MIS 3 was marked by sharp climatic oscillations: relatively milder interstadials alternated with severe stadials. In western Europe these changes could occur on timescales much shorter than conventional historical periods. A date around 31,868 BCE therefore belongs to an unstable environmental threshold, as the British–Irish Ice Sheet was expanding towards the far greater extent it would achieve later in the glacial cycle.