Submergent and Emergant features
When do they form ?
They form when the eustatic rise in sea level takes place faster than the isostatic rebound after an ice age. Basically, the water starts to flood the land and fills up landforms on the land.
= A river valley that’s been flooded by the eustatic rise in sea level, usually where a river meets the ocean. They are created by rising sea levels flooding river valleys .
Rias have a gentle long section and cross-profile typical of a river valley and usually a dendritic drainage system.
They’re wide and deep at their mouth, becoming narrower and shallower the further inland they reach.
This is because river floodplains vanish beneath rising water, but the middle and upper course valleys are filled with sea water. This leaves the higher land dry, thus producing this feature.
In Devon and Cornwall the sea level rose and drowned the valleys of the rivers flowing off Dartmoor and uplands of Cornwall.
Good Examples of Rias;
ü Fowey estuary in Cornwall
ü Kingsbridge estuary in South Devon
Fjords are drowned U shaped glacial valleys. They are typically found on;
ü The coast of Norway
ü The south west of New Zealand
ü British Colombia in Canada
ü And Greenland