A Stratigraphic Analysis of The Slieve Bloom Mountains in Offaly/Laois Counties, Ireland

Abstract

This is a study of the Slieve Bloom Mountains of Ireland, situated between Offaly and Laois County. The Slieve Bloom is the oldest mountain range in Europe, which once reached a peak elevation of 3,700m but stands at an elevation of 527m today. The mountains, formed during the Cordilleran Orogeny, provide profound evidence of depositional history through excellent preservation of several rock types. Most notably, the mountain range contains a notorious unconformity between Silurian age rocks and the Devonian age Old Red Sandstone, a time gap of roughly 70 million years. The Silurian rocks constitute a single formation (the Capard Formation), outcropping in 16 inliers of the area. The Old Red Sandstone overlies the Capard Formation, making up the unconformity.