The role of thrust tectonic models in understanding structural evolution in NW Scotland

Abstract

AbstractThe NW Highlands of Scotland have been an important test-bed for concepts in thrust tectonics. Here, research following the breakthrough publication of the 1907 memoir is reviewed, especially that relating to structural evolution in the Moine Thrust Belt. This belt was WNW-directed, involving cover sediments and thin sheets of crystalline basement. Displacements total 50–100 km within a branching array of thrusts. There are significant lateral variations in imbricate thrust geometry and localization behaviour. Following the application of linked thrust tectonic models in the 1980s significant attention has been directed at deducing thrust sequences, patterns of strain localization, folding styles and the significance of extensional tectonics as part of the structural evolution. The key has lain in deducing the kinematic linkages between thrusts and other structures, tracing displacements and examining the consequences of structural interpretations through geometric restoration. Thrusting models have been up-scaled to the crust. However, these linked kinematic approaches have been applied only hesitantly to the ductile structures of the Moine Thrust Sheet where structural research has focused on outcrop-scale deformation, especially of folds. Consequently, the larger-scale significance for Caledonian tectonics of thrust systems in the NW Highlands of Scotland has yet to be developed fully.