The landscapes of the Geopark represent a complex Earth history dating as far back as 900 million years ago. With evidence of mountain building and destruction, searing hot deserts and warm tropical oceans, and of icy wastelands and water-worn caverns, the rocks and landscapes of the Geopark are nothing short of amazing.

Limestone is the dominant rock type that gives the landscape at Marble Arch Caves Global Geopark its unique character.  It was formed around 330,000,000   years ago during the Carboniferous geological period. At that time, the area covered by Ireland today was actually beneath a shallow tropical sea. The limestone was formed from a mixture of the lime mud that collected on the sea floor and the remains of the sea creatures that lived there.  Later, mudstone and sandstone were laid down on top of the limestone. Limestone can be dissolved in weakly acidic water, like rainwater therein creating an array of spectacular, karst or limestone features such as caves, limestone pavement, depressions such as dolines to name but a few.

The use of the written word ‘million’ is intentional for readability purposes.