prize9-6, Exercise 3: Raised beaches and land movement

Model answer (check the details):

A raised beach is an old shoreline, with beach deposits and sometimes sea caves, now above the present high-tide line. It shows that the land has risen relative to the sea since the beach formed.

Why Scotland rose: during the last ice age the weight of thick ice pressed the crust down. As the ice melted, the crust began to rebound, and the process is still going on slowly (isostatic rebound). Parts of southern Britain, which lay at the edge of the ice and were pushed up, are now sinking in response.

Other factor: global sea level rose as the ice melted, so what we see on a coast is the balance of the two.

Care: the rates are small, in the order of millimetres a year, and should be quoted from a source such as the British Geological Survey.