The BIRM-166 Freshwater Horizon
Archived: 25 September 2026
Rather than a datable event, 30,694 BCE represents a broad Late Pleistocene interval in Ireland. Derryvree, County Fermanagh, preserves freshwater silts between glacial tills, indicating locally ice-free, wet tundra with sparse shrubs, sedges, aquatic plants and insects before renewed glaciation. Its radiocarbon range spans millennia, while ice-sheet expansion and timing remain uncertain. Castlepook Cave, County Cork, contains Marine Isotope Stage 3 fauna including reindeer, mammoth, giant deer, bears, wolves, Arctic foxes and hyaenas, revealing intermittent ecological links with Europe. A possibly cut-marked reindeer bone suggests human activity, but cannot establish settlement. Evidence documents environments and fauna, not societies or events.