Aspects of the Geology of NW Scotland

(The following text is adapted from an essay on Assynt Geology hosted at earth.leeds.ac.uk and written by Rob Butler, University of Aberdeen.)

The NW Highlands of Scotland contain a spectacular diversity of rocks recording three billion years of earth history. They also offer insights on ancient environments, the processes that formed ancient mountain ranges and the erosion of these landscapes. In more recent times the landscape has been sculpted by ice-sheets, which speak of climate changes during human existence.

Introduction

One of the key features of the geology of NW Scotland relate to an ancient period of mountain building – the Caledonian. This ancient chain once included most of northern Britain. The most striking effects of the Caledonian system are shown by rocks in the Scottish Highlands. Rocks are tightly contorted and strongly recrystallised by the heat and pressure to which they were once subjected. But not all of Scotland was caught up in the Caledonian mountain belt. The Caledonian “Foreland zone” (Fig. 1 inset) is a tract of geology that preserves a history of geological events much older than the Caledonian. The edge of the Caledonian mountain belt (the so-called “Caledonian front” that limits the foreland) runs from Durness – on the Scottish north coast, down to Skye.

 

Precambrian Rocks

Cambrian Sediments

The Moine