Work of Waves

Learning objectives:…Explain the processes of erosion, deposition and transportation at the coast.…Explain how the process of erosion creates caves, arches and stacks.…Identify different types of erosion and weathering that occur on the coast.

Prediction…How may this change in 1000 years

The formation of headlands and bays

Cracks Become Caves

Cave formation on Ballintoy coast, Ireland

http://www.youtube.com/watch?v=2fS2Swi0q-U&feature=related

Caves Become Arches

An arch on Lighthouse Field state

beach, California

Arches Become Stacks

A stack on the South Devon coast

• Joint or fault in resistant rock• Roof of arch becomes too heavy to be supported and collapses• A stack is an isolated part of a cliff• The stack us undercut and collapses to leave a stump• Waves cut through headland to form an arch which is continually

widened at its base• Abrasion and hydraulic action of waves widens the weakness in

the cliff to form a cave• Chemical weathering from the waves and rain cause the rocks to

be weathered• Biological weathering from roots occurs at the top of the rock.

Terminology used today:

New words:HeadlandBayCliffCrackCaveArchStack Stump Coastal retreat

Words we should have also used:ErosionWeatheringHydraulic actionSolutionAttritionabrasion

• http://www.bing.com/videos/search?q=formation+of+a+stack+coasts&view=detail&mid=0928E2F0EE5E7E3E134D0928E2F0EE5E7E3E134D&first=0

• http://www.bing.com/videos/search?q=formation+of+a+sea+stack&view=detail&mid=3560880BE2BA51435BB53560880BE2BA51435BB5&first=0