Eustatic And Isostatic Sea Level Change

Question 1

Eustatic sea level change

Answer 1

• occurs when the total amount of water is added to and there is a global sea level rise
• can be due to thermal expansion or changes in salinity which increase it
• can be caused by glacio-eustatic change e.g. Melting of land ice
• last interglacial was 11,700 years ago

Question 2

Isostatic sea level change

Answer 2

• Regional change in sea level, caused by the change in isostatic balance between the crust and the asthenosphere
• isostatic rebound occurs when the weight affecting the isostacy is released, glacio-isostacy, hydro-isostacy

Question 3

Raised beach

Answer 3

Westward ho

• as the weight of land ice melts isostatic uplift occurs causing the coast to emerge out of the sea
• features of a raised beach, retreated sea walls and old beaches, sometimes with caves retreated in to the coast

Question 4

River rejuvenation

Answer 4

River Nile

• formed when sea level drops or land level rises, this forms a water fall where river meets the ocean.
• the waterfall migrates upstream making the river sides extremely steep

Question 5

Rias

Answer 5

Kingsbridge estuary Devon

- flooded river valley formed when there is an overall rise in sea level and the river valleys flood