Limestone is a sedimentary rock formed 340 million years ago from the accumulation of calcium carbonate in warm tropical areas. Fossils of corals and shelfish are commonly found in limestone. It forms terrain like hills, cliffs, and pavements due to its resistance to weathering and presence of joints and pores that create sinkholes. Limestone landscapes typically have steep valleys, thin soils, and underground caves and streams.

2. Formed during carboniferous period 340
mil years ago
Formed by accumulation of CaCO3 in
warm tropical areas
Corals and shelfish found as fossils in this
rock
Forms bands – e.g. Pennine Hills in UK,
Mendips

3. Tough, resistant rock
At coast e.g. South Wales, forms towering
cliffs
Weak to Chemical weathering
Lots of horizontal and vertical joints
Permeable

4. Tends to form high ground
With exposures of bare rock, steep-sided
valleys or gorges
Thin soils due to weathering – used for
grazing of sheep

5.  Limestone pavements – bare rocky surface
with blocks (clints) seperated by enlarged
joints (grikes). Chemical weathering makes it
smooth
 Swallow hole – enlarged joint where water
falls
 Dry Valleys – mostly formed at the end of last
ice advance, where water tables were higher
and rock was frozen
 Cavern – large underground cave
 Resurgence – streams that emerge from
underground.

6. Stalactite – water with lots of dissolved
CaCO3 drips from the roof and deposits
some. Formed after hundreds of
thousands of years
Stalagmite – Shorter and stubbier due to
the drips splattering on the ground.
Pillar – when ‘tite and ‘mite combine.
Curtain – broad deposit of CaCO3 due to
many drips or small streams.