Landscape development

Karst Landscape

exposed limestone

When limestone is exposed at the surface it is chemically weathered by carbonation to form a karst landscape

E.g The Burren in country Clare

ice age

It is believed that part of the soil covering this area was removed by glacial erosion during the last ice age

• This is how limestone rock is exposed to carbonation.

carbonation

• a chemical weathering process that occurs when rain absorbs CO₂ as it falls from the atmosphere

• This forms a weak carbonic acid

• This carbonic acid slowly dissolves limestone on the surface and underground

Limestone

• limestone is a jointed and layered sedimentary rock

joints

• joints are vertical lines of weakness in limestone, they are enlarged by carbonation

• Overtime joints get wider and deeper and form Grikes.

Clints

• the slabs of rock separated by grikes are called Clints.

• Clints and Grikes result in a limestone pavement landscape.

Igneous rocks

• Igneous rocks occur when magma rises, cools and solidifies.

• when magma reaches the surface, it forms Extrusive rock - E.g Basalt

• When magma cools and hardens within the crust, it forms Intrusive rock - E.g Granite

Antrim-Derry Plateau

• example of extrusive igneous rock

• The plateau was formed when lava from a divergent plate boundary cooled quickly on the surface.

• Occurred 65 million years ago when the North American plate pulled apart from the Eurasian plate, lava split from the mantle onto the surface.

• The lava cooled to form igneous basalt rock.

Giant’s Causeway

• part of the Antrim-Derry Plateau

• it has 60,000 basalt columns, formed when the lava cooled in a river valley

• Because it cools slowly, large crystals formed.

• The lava cooled and broke into hexagonal columns.