Castlepook’s Tundra Threshold
Archived: 14 September 2026
Around 31,759 BCE, a modern label within late Marine Isotope Stage 3, Ireland was a cold, changing periglacial landscape before the British–Irish Ice Sheet reached its maximum. Derryvree and Greenagho deposits show wetlands and regionally ice-free ground, while pollen, insects and plant remains indicate sparse tundra vegetation. Castlepook Cave preserves MIS 3 fauna including mammoth, reindeer, giant deer, hyaena and Arctic fox, though bone accumulation complicates interpretation. A marked reindeer femur may indicate brief human butchery, not settlement. Lower seas may have eased movement, but routes remained uncertain. Subsequent ice advance buried or destroyed much archaeological evidence across Ireland thereafter.