Geological History of Ireland

Ireland's Geological History

Early Continental Configuration (~850 MYA)

• Ireland was split between two continents: Laurentia (North) and Avalonia (South).
• These continents were separated by the Iapetus Ocean.

Closure of the Iapetus Ocean (~470 MYA)

• Laurentia and Avalonia plates converged, causing the Iapetus Ocean to disappear.
• The boundary is marked by the Iapetus Suture, running across Ireland from Clogherhead to the Shannon Estuary.
• Marine sedimentary rocks from the Iapetus Ocean are found in Howth Head, Bray Head, and the Sugarloaf Mountain.

Caledonian Orogeny (490-390 MYA)

• Continued plate collisions resulted in mountain building.
• Formation of the Bluestack and Wicklow fold mountains.

Carboniferous Period (~400 MYA)

• Ireland moved closer to the equator and sank beneath a warm tropical sea.
• Formation of sedimentary rocks like sandstone and limestone.
  • Example: The Burren in Co. Clare.

Armorican Orogeny (~250 MYA)

• Collision of the Eurasian and African plates.
• Formation of mountains and valleys in Munster.