BIRM-166 and the Fermanagh Thaw
Archived: 21 September 2026
The modern label 30,992 BCE cannot identify a precise Irish event, but overlaps the calibrated range of BIRM-166, a freshwater deposit at Derryvree, County Fermanagh. Sediments between tills show a locally ice-free MIS 3 interval, with treeless, sedge-rich wetland, pools, bogbean, mosses and cold-adapted insects. Ireland’s climate and ice cover varied regionally before the Last Glacial Maximum; Crag Cave records milder episodes. Castlepook Cave fauna demonstrates cold-stage reindeer, mammoth, giant deer, predators and lemmings, though deposits are not contemporaneous. A possibly cut-marked reindeer bone suggests, but cannot prove, human presence. Glacial erosion and disturbance limit conclusions; settlement evidence is absent.