Abstract

The geology of the Minches and the Sea of the Hebrides is controlled by three principal faults — the Minch Fault, the Camasunary-Skerryvore Fault and the Great Glen Fault. These faults form the westerly margins of deep asymmetric troughs filled with upper Palaeozoic and Mesozoic sediments, in places injected by Tertiary intrusives and overlain by Tertiary volcanics and sediments. Gravity, magnetic, seismic reflection and refraction studies have been combined with a range of sampling and drilling tests to derive a structural and stratigraphic history. In the principal basins, the infilling rocks, of which New Red Sandstone, Jurassic, Cretaceous and Tertiary samples have been obtained, attain maximum thicknesses of 3-4 km (interpreted from geophysics).

The basins are thought to have developed by down-warping and down-faulting in an extensive area of post-Carboniferous sedimentation which probably included what are now the continental shelves of northern Britain, Norway and east Greenland. Structural affinities are apparent throughout these areas and can be compared with features of the Canadian shelf off southern Labrador and eastern Newfoundland.