Castlemore Quarry, Crookstown, County Cork

This rock records the life of an active fault where limestone (formed in a warm tropical sea 340 million years ago) has been repeatedly fractured and mineralized during earthquake events.

Fracturing can be seen on some faces as grey fragments cemented together by a cream-coloured mineral, dolomite. In other areas, cavities in the limestone contain saddle-shaped crystals of dolomite and prismatic crystals of aragonite. The ‘rusty’ brown areas of the rock testify to the movement of oxidised iron and manganese-rich solutions through the fault.

The stone is quarried by Roadstone Wood for a variety of purposes at Castlemore Quarry, near Crookstown, County Cork.