Causes of sea level change Flashcards
What is a eustatic change as a result of?
global sea level changes
What happens during an ice age?(eustatic)
there is less water in the ocean as precipitation falls as snow - sea levels fall
What happens when the ice melts? (eustatic)
the volume of water begins to increase, so sea levels rise
What else is increasing sea levels?(eustatic_
global warming - due to thermal expansion of the oceans
Where does eustatic changes occur?(EG)
Greenland
When do isostatic sea level changes occur?
on a regional/local scale as a result of changes in the Earth’s crust
What are isostatic changes a result of?
when large ice sheets cover the land it makes land sink - when ice melts it rises again - isostatic readjustment
What can tectonic activity result in?
eustatic sea level change over a much larger time scale by decreasing/increasing the size of ocean basis
What is likely to have caused a sea level rise?(tectonics)
emergence of the mid-Atlantic ridge
What will the spreading of ocean floors likely to have resuled in?
eustatic falls in sea level
What is a relative rise in sea level called?
positive movement of base level
What is a relative fall in sea level called?
a negative movement of base level
What is base level?
the lowest level to which a river can erode
What does a fall in base level create?(landforms)
- raised beaches
- relict cliff lines
- marine platforms
What does a rise in base level create?
- rias
- fjords
- dalmation coastlines
