Types Of Coastlines Flashcards
(10 cards)
What are the two types of coastlines
Submergent
Emergent
What is a submergent coastline
Has a rising sea level
What is an emergent coastline
Has a falling sea level
What landforms are formed by submergence
Rias
Fjords
Dalmatian coastline
What landforms are formed by emergence
Raised beach’s
Marine platforms
What is a rias
Drowned river valley
A river valley is carved out by a river over time, creating V shape
At the end of a post glacial period sea levels rise due to melting glaciers and thermal expansion of water.
The rising sea floods the lower part of the river valley and its tributaries.
This creates a drowned, irregular coastline called a ria, with deep, narrow inlets extending inland.
What is a fjord
Glaciers erode deep U shaped valleys through plucking and abrasion
Glaciers often follow the path of pre existing river valleys
When glaciers retreat/melt they leave behind steap sided valleys
These valleys are then flooded by rising sea levels
What are Dalmatian coasts
Form where valleys and ridges run parallel to the coast
During post glacial, sea levels rise, lower parts of these valleys are flooded
The ridges however remain above sea level, creating long islands that run parallel to the coast
Creates multiple islands that align with the original topography
What are raised beaches
Sea level was higher in the past.
Waves built a beach at that higher sea level.
Land rose or sea level fell (e.g. due to tectonics or melting ice).
Old beach is now above current sea level — a raised beach.
What are marine platforms
Constant erosion at base of the cliff forms a notch
Overtime the notch deepens and makes cliff above unstable, causing it to collapse
As the cliff retreats inland, a flat area of rock is left behind
This is a wave cut platform which is visible at low tide
