BIRM-166’s Periglacial Pool
Archived: 17 September 2026
Around 31,443 BCE, Ireland lay within the unstable cold climate of Marine Isotope Stage 3, before the Last Glacial Maximum. Derryvree, County Fermanagh, preserves Birm-166, organic freshwater sediments between glacial tills, dated broadly to 36,900–31,700 cal BP. Its plants and insects indicate an ice-free local tundra wetland with mosses, sedges and cold-adapted flora, rather than continuous national ice cover. Greenagho supports episodic ice-free terrain. Lower sea levels altered coastlines, while cave remains indicate reindeer, mammoth and hyaena regionally. A marked Castlepook reindeer bone may suggest human activity, but lacks secure context. No evidence supports permanent settlement, polities, farming or trade.