Sea Level Change Flashcards
Eustatic change?
When the sea level changes due to an alteration in the volume of water in the oceans. It could also be a change in the shape of an ocean basin and therefore a change in the amount of water the sea can hold
When does eustatic change take place ?
Eustatic change is always a global effect. It take place during or after an ice age
Isostatic change?
Increase or decrease in the height of the land. Height increase causes sea level decrease, height decrease causes sea level increase
Local sea level change
Isostatic formation?
During a glacial period, ice builds up on land causing the land to decrease slightly, and sea levels to rise. Once the ice melts, pressure is taken off the land allowing it to rise again and sea level to decrease
Eustatic formation?
During or after a glacial period, water is frozen, suspending the hydrological cycle. This results in water being taken out but not coming in, causing sea levels to fall. As the ice melts, sea levels will be replenished and rise again
Submergent landforms
Landforms created by rising sea levels are known as submergent as they have been ‘submerged’ by the water
Emergent landforms
These are created as a result of rising out of the water
Submergent landforms- rias
A Ria is a river valley that has been flooded by the eustatic rise in sea level.
They’re almost the same as a normal river valley however they have more water in them.
They have similar cross sections as rivers in the lower course
The floodplain or Rias get flooded, altering the cross profile of a Ria ever so slightly so that it includes the floodplain
Fjords
Fjords are steeper and deeper variants of Rias that are relatively narrow for their size.
They have a U-shaped cross profile and are often found in icy regions of the world.
They are flooded glacial valleys
Landforms or emergence- raised beaches/ wave cut platforms
These are found above current sea level. These no longer experience coastal erosion but are still weathered, often biologically and chemically
