The Glaciations of Ireland

Ireland was heavily impacted by glaciation during the Pleistocene. Multiple ice advances and retreats shaped the island's landscape, with the most significant glaciation occurring between 30,000 and 10,000 years ago.

Glacial Landforms:

• U-shaped valleys: Glaciers carved through pre-existing river valleys, creating steep, U-shaped profiles. Examples include the valleys in the Wicklow Mountains and parts of County Kerry.
• Drumlins: These elongated hills of glacial debris formed beneath ice sheets. They are common in the central and northern parts of Ireland, particularly in County Louth and County Antrim.
• Erratics: Large boulders that were carried by glaciers and deposited far from their source. These are scattered across Ireland, often in areas where the rock type is different from the local geology.
• Moraines: Accumulations of debris (such as rocks, gravel, and sand) left behind by glaciers. Terminal moraines mark the furthest extent of the ice sheets, such as those found in County Down and County Antrim.

Glacial Features:

• Fiords: Coastal features formed when glaciers eroded valleys that were later flooded by the sea. An example is Killary Harbour in County Galway, which is Ireland's only fjord.
• Pleistocene lakes: As glaciers melted, they left behind large bodies of water, some of which formed lakes, such as Lough Neagh and Lough Erne.

Climate and Post-Glacial Effects:

• After the glaciers retreated, Ireland experienced a shift to a warmer and wetter climate. This allowed for the re-colonisation of the land by vegetation and animals.
• Rising sea levels due to melting ice created Ireland's modern coastline, and the glacial period had a lasting impact on the country's physical geography.

Evidence of Glaciation:

• The presence of striations (scratches in rocks caused by moving ice) and glacial tills (mixtures of rocks and sediments) across the landscape provide clear evidence of Ireland's glacial past.