The evaluation of Laxfordian deformation in the carloway area, Isle of Lewis, Scotland

Abstract

The paper outlines an investigation of methods of estimating variations in strain suffered during the tectonic evolution of a high-grade gneiss complex. A map has been produced representing the Laxfordian deformation shown by the Lewisian rocks of the Carloway area in Northwest Lewis. The map shows that modifications of the pre-Laxfordian Scourie Dykes — their loss of discordance, the nature of their contacts and their folding and boudinage — are paralleled by a series of modifications in the host rocks, “the grey gneisses”. Strain contours have been derived and tend to be oriented parallel to the strike of the rocks. The boundaries between high and low strain areas are transitional. One of the main values of such an analysis is that it aids the reconstruction of the pre-Laxfordian structural pattern in the area.