The Blackstones Tertiary igneous complex

Abstract

Synopsis Seismic, gravity, magnetic and sampling evidence show that the Blackstones Bank in the Sea of the Hebrides is the outcrop of a Tertiary ultrabasic intrusion whose form may be approximated as a vertical cylinder of diameter 16 km and depth to base 22–30 km. The intrusive body is partly overlain by Mesozoic and younger sediments. Little disturbance is seen in the country rock of either the roof or walls of the pluton.