8.6. Coastlines of submergence

Coastlines of submergence are formed in Coastal areas which have become lowered below current sea level. The cause is rise in sea level in consequence of ice melting since the last ice age. This group includes Ria, fiord, estuarine, and Dalmatian or Longitudinal coasts.

a) Ria Coasts: A ria coast is formed when a non-glaciated highland coast becomes submerged and the valleys filled with sea water. These submerged valleys are often V- shaped. This type of coast is found in north-western Spain and south-western Ireland.

b) Fiord (Fjord) Coasts: A fjord is a narrow, high-walled, and very long submerged glacial valley. Fjords are formed when a descending glacier carves a U-shaped valley into the bedrock. When these fjord are submerged fjord coast is formed.

c) Dalmatian or Longitudinal Coasts: These coasts are formed when a mountain ridge running parallel to the sea coast is submerged. In this mountain ranges become chains of islands resembling patches on body of Dalmatian dog.

d) Estuarine Coast: Estuary/estuarine coasts are coasts where lowland coasts are submerged, flooding river. Their entrances are sand and silt free, Thames of Britain are the example of such type of coasts.