Submergent coastline

[2] Another common cause of isostatic change that can result in a submergent coastline is tectonic action.

[1] Many rias were formed by the rise in sea level after the melting of vast continental glaciers.

[3] Rias commonly have a widening funnel shape and gradually increasing depth as they move towards the coast.

The widening and deepening of the ria towards the sea usually causes an exaggerated tidal effect within the estuary.

A section of a glacially eroded valley is flooded by the sea when a fjord is formed.

A submergent landform: the drowned river valley ( ria ) of Georges River in the greater Sydney area, Australia
Sydney Harbour is one example of a ria.
Map showing the Dalmatian coast of the Dalmatia region of Croatia. The narrow islands running parallel to the coast can be clearly seen.