The history of the Western Lewisian in the Glenelg Inlier, Lochalsh, Northern Highlands

Abstract

Synopsis A detailed field and petrographic study has been made of Lewisian rocks forming the western half of the Glenelg inlier. It is concluded that in this part of the inlier an earlier metamorphic and igneous complex was affected by Scourian metamorphism and intruded by a series of dykes (Scourie dykes) before the ‘Caledonian’ orogeny. There is no evidence of a Laxfordian event. From the metamorphic and deformational episodes recognised in the adjacent Moines a sequence of Caledonian events is established for the rocks of the inlier. It is found that although the rocks have been texturally and mineralogically modified, the outline of their earlier Lewisian history and their essential Scourian characteristics have been preserved. Correlation o f the later Caledonian events with the formation of mylonites in the Moine Thrust Belt supports the Precambrian age of the early metamorphic and structural events in the Moines indicated by isotopic age dating.