More Geological Facts...

The type of sedimentary rock that is found at the quarry is carboniferous limestone and this occurs widely across Great Britain and Ireland.

Principal characteristics of carboniferous limestone include:

  • The predominant mineral inlcuded 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 encased in mud 363 - 325 million years ago
  • The rock colour is light- to mid-grey
  • It is composed of horizontal layers of rock (beds) and vertical joints many of which have now been uplifted and have steep angles of repose
  • Limestone is permeable to water - where water seeps through the vertical joints (weakness in the rock) and creates sub-surface features where the action of weak hydro chlorate acid present in rain water eats away the rock over many millenia
  • The main sub-surface features are caves which come about from the carbonation process where carbon dioxide dissolves in an aqueous solution. As this process is reversible, the redesposition of calcite forms stalactites and stalagmites in caves over long periods of time.

 

Carboniferous Limestone       Angle of repose of the bedrock
 

Old quarry working benches

    Close up of working benches
  Natural weathering of rock - showing slippage after frost action  

 

 

 

 

 

Relics of final face blasting in the southern wall