sea level changes

Question 1

what is eustatic sea level change

Answer 1

it is caused by a change in the volume of water in the sea, or by a change in the shape of ocean basins

Question 2

what are the main causes of eustatic sea level change

Answer 2

1. changes in climate:
   - increase in temperature causes ice sheets to melt which increases sea level, increasing temperatures cause water to expand which increases sea level even further
   - decrease in temperature causes more precipitation to fall as snow, this increases the amount of water that is stored by glaciers, which decreases sea level
2. tectonic movements in the earths crust that alter the shape and volume of ocean basins

Question 3

what is isostatic sea level change

Answer 3

it is caused by vertical movements of the land relative to the sea. any downward movement of the land causes sea level to rise locally, while the uplift of land causes sea level to fall

the effects are always local and the main causes are:
1. uplift or depression of the earts crust due to accumulation or melting of ice sheets. slow uplift of land can continue for thousands of years after the weight of a retereating glacier has gone. accumulation of sediment, mostly at the mouths of major rivers can also cause depression

2. subsidence of land due to shrinkage after abstraction of ground water
3. tectonic processes