1. Coast of submeregance
2. Coast of emergance
3. Neutral coasts
4. Composite coasts
1. Coast of submergance
These coasts have sunk in relation to the sea level and was caused by crustal movements ot as a result of the rise in sea level. we can distinguish between THREE types of coasts that have been submerged -
a) Ria coast
These coasts form when a river-eroded hilly land is submerged. The valleys lay at right angles to the coast and gets filled with water from the ocean. The result is funnel-shaped bays which becomes deeper towards the open sea. The former hilltops form islands
b) Fjord coasts
These coasts are formed largely by ice-eroded topography which has been submerged. After the ice glaciers have been melted the valleys became filled with sea water. The valleys will be U-shaped with very steep and high sides. The valleys are shaloower closer towards the deeper ocean where the glacial material was deposited.
Generally, fjord coasts are unsutable for harbours because it is to deep for anchorage and lack of space to build harbhours. Although, fjor coasts provide good breeding grounds for fish and a popular tourist destinations.
c) Dalmation coasts
When a mountainous landscape which runs parallel to the coast becomes submerged, the result is a long, narrow strecth of islands with longitudinal bays.
These coasts provide good sheltered harbours. Communication with the interior however, is difficult as the valleys do not penetrate inland.
2. Coasts of emergance
When the land rise in relation to the sea level coatlines will be situated higher above and further away from current sea level. Part of the former sea bed can now be found above the sea level. Therefore, the shape of the new coast will be determined by the former sea bed.
3. Neutral coasts
Three types of neautral coasts can be identified -
a) Delta coasts
Where rivers with a high sediment content enters the ocean the deposition can result in deltas to form e.g. the Mississippi delta.
b) Volcanis coasts
Where lava is flowing into the ocean it cools and solidifies. New land is thus formed and the coast is extended seawards e.g. Hawaiin islands.
c) Coral coasts
Coral will form when the following requirements are met -
- water temperature above 20˚C
- water not deeper than 30m.
Coral reefs protect the coast from wave attack but limits passage through the reefs.
4. Composite coasts
These coasts reveal characteristics that are typical of any two of the coasts already discussed.
