After the ice

One of the most dramatic effects after the ice was the changing position of the coastline in response to changes in relative sea level.

Relative sea level has varied around Scotland, probably rising all the time in Orkney, Shetland and the Western Isles over the last 11,500 years, but elsewhere falling, then rising to a maximum 6,000-7,000 years ago, before falling again gradually to its present level.

An unstable legacy

The glaciers left behind many unstable rock slopes. Screes accumulated, blanketing steep slopes below cliffs. Where screes have buried their crags, rock falls have ceased, and vegetation taken over. Some big crags collapsed in massive rockfall events, leaving large jumbles of boulders on valley floors (e.g. the Lost Valley in Glencoe). In some cases whole hillsides moved downslope (e.g. along the Trotternish Peninsula on Skye).

In the valleys

Rivers have reworked glacial and meltwater deposits. In the river valleys, sequences of terraces formed as the rivers adjusted to fluctuating, but generally lower volumes of water and transported sediment. Abandoned channels are often visible on these terraces, and alluvial fans have been deposited from side valleys onto the terrace surfaces (e.g. in Glen Feshie).

Green and growing

After the ice melted, we know from pollen records that vegetation began to develop on the bare mineral soils from about 14,000 years ago. The speed of plant colonisation and soil development were affected by the varying nature of the surface material, and by the changing climate, being retarded during the cold interval when the Loch Lomond Readvance occurred (12,900-11,500 years ago). Crowberry, birch and willow were early colonisers, often succeeded by ash and hazel and later by oak, elm and pine. During wetter periods, peat expanded in many parts of the Highlands (especially the blanket bogs of Caithness and Sutherland), as well as the extensive lowland raised bogs in Central Scotland. At the same time, extensive heathlands were developing.

Clues to animal life

Deposits in caves in Assynt have preserved important clues about the animals that lived in Scotland during and after the ice. The bones of animals no longer found in Britain, including the brown bear, reindeer, lynx and wolf, have all been unearthed.