Geology and Palaeontology

Carboniferous limestone, which occurs widely across Great Britain and Ireland, is the sedimentary rock found at the quarry.

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Principal characteristics of carboniferous limestone include:

 

• The predominant mineral in the rock is calcium carbonate, which is the main component of the shells of marine organisms, plants, and early life forms. In this case, the shells and hard parts of marine animals were encased in mud 363 - 325 million years ago.

• The rock colour is light- to mid-grey.

• It comprises horizontal layers of rock (beds) and vertical joints, many of which have been uplifted and have steep angles of repose.

• Due to its permeability, limestone allows water to seep through its vertical joints, creating subsurface features. Over many millennia, the action of weak hydrochloric acid present in rainwater gradually erodes the rock, forming unique subsurface features.

• The main subsurface features are caves, which result from the carbonation process, where carbon dioxide dissolves in an aqueous solution. As this process is reversible, the redeposition of calcite forms stalactites and stalagmites in caves over long periods.