Rocks are naturally occurring material composed of minerals.
Limestone solution: Limestone is made up of calcium carbonate (CaCO3), originally formed from the skeletons of microscopic sea creatures in tropical seas many millions of years ago. Limestone landforms (sometimes called 'karst scenery') are highly distinctive. They form by erosion because limestone rocks gradually dissolve.
Rainwater is naturally slightly acidic (approx pH 6) because carbon dioxide in the atmosphere combines with water to form carbonic acid: CO2 + H2O → H2CO3.
When this acidic rain falls onto limestone, it reacts with the limestone to form calcium bicarbonate, which is carried away in solution: H2CO3 + CaCO3 → Ca(HCO3)2.
Limestone pavements (clints and grykes)
Sinkholes and swallowholes
Stalactites and stalagmites
Case study area Malham Cove in the Yorkshire Dales.
Igneous intrusions (sills and dykes)
Chalk and clay landscapesEdit
Scarp and dip slopes