2B.7b- Norwegian Fjords & Raised Beaches Flashcards
How do submergent landforms form?
They form when eustatic rise in sea level takes place faster than the isostatic rebound after an ice age, so, the water starts to flood the land.
How is a fjord created?
1) A glacier (big mass of ice) begins to retreat
2) it begins to erode the land by cutting through interlocking spurs forming a v-shaped valley with truncated spurs on alternate sides through abrasion and freeze-thaw.
3) As the mass continues to move, it erodes the valley floor through plucking and abrasion.
4) at the end of the ice age, sea levels rise and fill up the u-shaped valley with water forming a Fjord.
Give an example of a location where fjords are found?
Largest fjord system is in a Norway, with the largest fjord called sognefjorden.
What is a Ria?
A river valley that has been partially inundated due to sea level rise usually after the melting of vast continental glaciers. These are formed at the base of a valley and are near open, large bodies of water.
Give an example of a ria?
Knightsbridge estuary, Devon, uk
What is another feature of a submergent coastline?
Dalmatian coastline
How are Dalmatian coastlines formed?
These form in areas where valleys, especially glacial ones lie parallel to each other.
When the valleys are flooded by the rise in sea level and synclines are eroded, the top section of the valley remains above the surface of the sea, forming a series of islands that run parallel to the coastline like the Dalmatian coast in Croatia.
Are emergent coastlines formed due to eustatic or isostatic sea level change?
This occurs due to isostatic sea level change.
How are emergent coastlines formed?
During the glacial period, isostatic change is caused due to the build up of ice on land which decreases then height of the land as the crust sinks due to compression. This gives the idea that sea level has risen, when it’s just the land submerging.
However, when the ice melts at the end of Holocene, the height of the land starts to increase again as it rises and sea level falls. Also known as isostatic rebound an example of this was Scotland which rose up where as the south-east became more submerged in water.
How are raised beaches formed?
These occur due to isostatic uplift of the land, in comparison to the sea. This can occur due to isostatic rebound or plate movement at a subduction plate boundary pushing the continental plate upwards.
