How do coastal landforms evolve as climate changes? Flashcards
What happens to sea level when temperatures fall?
Sea level decreases.
Why does sea level decrease when temperatures fall?
Due to more precipitation falling as snow and then freezing meaning more water is on land. The opposite of thermal expansion takes place and water molecules shrink in the colder temperatures.
What is isostatic change?
Local changes caused by subsidence or uplift of the crust related either to changes in the amount of ice on the land, or to growth or erosion of mountains.
What is eustatic change?
Global sea level changes related to changes in the volume of water in the ocean.
Give an example of past climate change causing sea level fall.
During the Riss period 108,000 years ago temps fell to 7 degrees below today’s level and thus sea level dropped by 100m.
What is an emergent landform?
A feature of coastal erosion that appear to have developed well above the current sea level.
Give examples of some emergent landforms.
Raised beaches, relict cliffs, cryoturbations.
Give examples of submergent landforms.
Fjords and Rias
What is a fjord?
A submerged glacial valley
What is a ria?
A drowned river valley.
When did Rias form?
In the post glacial sea level rise of the Flandrian Transgression.
Where may you find some Rias?
The south coast of Devon and Cornwall
Give an example of a fjord
Sogne Fjord- Norway- nearly 200km long
What does a fjord consist of?
Glacial rock basin with a shallow section at the end known as the threshold.
What has happened to sediment entering the fjord in recent years?
There has been more of an infilling of sediment and the volume has increased as glaciers have retreated.
