Derryvree Organic Silts
Archived: 9 September 2026
31,929 BCE is a modern label for a Late Pleistocene phase, not a recoverable Irish year. During Marine Isotope Stage 3, Ireland experienced cold, unstable conditions before the Last Glacial Maximum, with fluctuating ice margins, sea levels and landscapes. Organic silts at Derryvree, County Fermanagh, dated broadly to 36,900–31,700 cal BP, indicate locally ice-free intervals and treeless wet vegetation. Cave deposits, including Castlepook, show cold-stage mammals occurred during the wider period, though not necessarily then. No securely dated human evidence exists. Later glaciation erased much evidence; surviving sediments, landforms and fauna provide an incomplete environmental record of developing Irish glaciation.