Landforms created by the fall in the sea-level

Landforms created by the fall in the sea-level

When the sea level falls the formally submerged landforms are exposed to form emerged landforms in highland and lowland coasts:




Emerged landforms in highland coasts

Raised cliffs. A raised cliff is a steep rock face along the sea coast that is no longer in contact with the sea. Before submergence, waves attacked coastal rock and through processes of abrasion, hydraulic action and solution, a notch formed, enlarged and deepened. With time, land above the notch lost support and collapsed to form a cliff.
When sea level falls, new cliffs are created and the old cliffs that are no longer in contact with the sea are left behind high above the present water level hence the name-raised. Raised cliffs are Found at Mombasa.

Raised terraces are former wave cut plat forms which are no longer in contact with the sea created by materials eroded from the cliff. When sea level falls, new wave cut plat forms are created and the old terraces which are no longer in contact with the sea and left high above the current sea level hence the name raised terraces.

Raised beaches. These are beaches which are no longer in contact with the sea left high above the current sea level.




Before submergence, sand and shingle materials are deposited by constructive waves to form a gently sloping platform called beach at the coast. When sea level falls, the beach loses contact with the sea and left behind high above the current sea level as a dry land hence the term-raised beach. For example Dar es Salaam, Mombasa, Tanga e.t.c

Raised caves, geos and blowholes. Continuous wave erosion against jointed coastal rock through abrasion, hydraulic action and solution create large holes in the cliff face called caves. When the roof of the cave collapses, it forms a narrow inlet called a geo and a blowhole when waves erode the roof of a cave to the surface.

When sea level falls, all these features reappear behind high above the current water level. The fall in the sea level in lowland coast creates coastal plains and Fiards.

coastal plains formed when the continental shelf is exposed after a fall in the sea level. The coast line of Coastal plains have no bays and head lands.




Fiards- are drowned u-shaped glacial troughs/ valleys formed along lowland coasts. They have a broader u-shaped profile than the fiord. For example the coast of south East Sweden, coast of Nova Scotia and Maine.

RELATED POSTS

%d bloggers like this: