Castlepook’s One Deep Mark
Archived: 20 September 2026
31,036 BCE is a modern notional date within Marine Isotope Stage 3, not a datable Irish event. Derryvree, County Fermanagh, preserves freshwater sediments between glacial tills, indicating an ice-free, treeless tundra wetland during a broad interval around 36,900–31,700 calibrated years ago. Castlepook Cave, County Cork, contains disturbed, long-accumulated remains of cold-stage mammals, including reindeer, mammoth, giant deer and predators. A deeply marked reindeer femur may record stone-tool butchery and a brief Upper Palaeolithic visit around 31,000 BC. However, it proves neither settlement nor continuity. These sparse archives document fluctuating ice, open habitats, animal movements and a cautiously inferred human action.