We have recently returned from Iceland and learnt about isostatic rebound. Isostatic rebound is when during the last glacial period, ice pushed down on the land masses (a bit like a memory foam mattress), now the majority of the ice has melted the land is rising, meaning relict coastlines are km away from the current coast and waterfalls are created.
The waterfalls we visited in Iceland such as Skógafoss and Seljalandsfoss are a result of isostatic rebound. These huge cliffs used to be the coastline before the land starting rising out of the water. The fact that this waterfall does not have a gorge (a gorge has started to form as the waterfall has retreated a short distance).
This article is an interesting and quick read around the topics of AS cold environments or GCSE ice on the land. It is also a good quick read for A2 atmosphere synopticity.