Geology of Durness

Very little igneous activity is seen in the Durness area but this small intrusion is one example within the gneisses at the eastern side of Sango Bay. It was formerly a deep molten body of magma that cooled deep within the crust to form a 'gabbro', this being similar to granites but formed from different minerals. Like granites, these have cooled slowly over time to form large crystals within the rock (photo above). Erosion to the present day has removed the upper layers of rock and now this rock is found at the present day surface at Sango beach. It has also been altered by past metamorphic events and hence is referred to as a 'metagabbro'. Large sections of gneiss that formed the walls of the magma chamber are also seen as lighter inclusions or blocks at the edges of the intrusion after being effectively 'ripped off' the chamber walls by the once molten fluids (photo below).