Limestone/Distinctive landscape - Geography Leaving Cert Notes/Sample answer

With reference to one rock type explain how it was formed and how it can produce a distinctive landscape.

·      Carboniferous limestone is a gray sedimentary rock. 

·      Limestone is classed as Organic sedimentary rock, unlike Sandstone witch is Inorganic and Gybsum witch is classed as Chemical.

·      The fact that limestone is Organic means that it is compiled from sediments that were once living. Limestone is made from Decayed marine life eg. Fish bones.

·      Limestone was formed on the bed of a warm sea 350-370 years ago.

·      The minerals that make up limestone are Calcium Carbonate (over 50%) and Calcite (crystalline Calcium Carbonate as well as clay and sand.

·      The above minerals were compacted (squeezed) together to release air and water by the pressure of the sea.

·      Cementing agents in the water bonded the decayed marine life together.

·      Lime stone is stratified (layered), Well Jointed and Permissible (water can pass through).

·      Limestone is soluble in Rain water, as Rain is a carbonic acid witch dissolves the calcium carbonate (the main mineral in limestone) This process is known as carbonation.

·      The bare surface is known as a limestone pavement.

·      In the Burren, Co. Clare limestone has managed to create a astounding, distinctive landscape.

·      The bare limestone has undergone weathering by rain. This left a distinctive limestone pavement landscape known as Karst.

·      To add to the distinctiveness of the Burren. There is a absence of soil as soil needs water to form.

·      This further leads to a lack of any vegetation as plants need soil and water to form.