Derryvree’s Sedgewater Archive
This was long before the Last Glacial Maximum, when the British–Irish Ice Sheet covered Ireland and extended over the surrounding continental shelf. Recent syntheses place the broad build-up of that ice sheet between about 31,000 and 26,000 years ago, with its largest overall extent reached later, around 26,000 calendar years before present. The ice did not advance as a single, uniform wall. Different sectors grew, flowed and retreated on different schedules, while climatic shifts changed the balance between snow accumulation, melting and iceberg calving. Around the notional date in question, Ireland was entering a consequential phase of that long expansion, but the available evidence does not support a simple picture of the whole island already sealed under continuous ice.