Some Geophysical Observations on the Great Glen Fault

Abstract

EARLIER geologists^1–3 have considered the Great Glen fault as a normal or dip-slip fault, while Kennedy⁴ interpreted it as a strike-slip fault, basing his view chiefly on a lithological similarity between the Strontian and Foyers granitic complexes, and he suggested that the former has been moved 65 miles south-west along the Great Glen fault. Shand⁵ has not found such characteristic features of strike-slip faults as slickensides or friction-grooves and mylonite. Collette⁶ thinks that the fault passes to the south-east of the Shetland Islands. Flinn⁷ has examined the submarine topography of the Moray Firth and has outlined a possible course of the fault. Wilson⁸ joins the Great Glen fault to the Cabot fault of North America. Riddihough⁹ has conducted a detailed magnetic survey off the north coast of Ireland and suggests the presence of two faults which may have some relation to the Caledonian fault systems of Scotland.