an organic, sedimentary rock. This means it was formed from the
remains of tiny shells and micro-skeletons deposited on the sea
bed. They were compressed to form solid rock. Limestone is made
up of calcium carbonate and reacts with diluted hydrocloric acid.
Limestone is formed in layers - called bedding planes. These bedding
planes contain vertical cracks called joints. Joints and bedding
planes make the rock permeable.
is the breakdown of rock by physical, chemical or biological processes.
Limestone areas are weathered when rainwater, which contains a weak
cabonic acid, reacts with limestone. When it rains limestone is
dissolved. Rainwater erodes the joints and bedding planes. In doing
scenery is created.
hole - An exposed limestone joint down which a surface river 'disappears'.
Clints and grykes - Rainwater flowing over an impermeable surface
will, on reaching (permeable) limestone, be able to dissolve the
joints into grooves called grykes, leaving blocks or clumps of
limestone in between called clints
pavements - Exposed clints and grykes.
Stalactite - Water dripping from the roofs of caves leave behind
microscopic particles of calcium carbonate. These build up as
icicle shaped stalactites.
Stalagmite - Drips splashing onto the cave floor
offer a wide range of opportunities to recreationists. This includes
- potholing, caving, walking, climbing, abseiling and many other
Study - Malham, Peak District
area of the Peak District National Park is an excellent case study
of a limestone area.