The Belhelvie mafic igneous intrusion, Aberdeenshire—a re-investigation.

Synopsis A total field ground magnetic survey and a programme of shallow drilling have been used to augment conventional mapping techniques in the preparation of a new map of the poorly exposed Belhelvie igneous intrusion. The revised map differs considerably from previous maps and increases the landward area of the intrusion by 6 km 2 . Several new rock units have been found including a thin noritic band on the western margin, a septum of country rock which splits the northern half of the mass in two and, east of the septum, a sequence of peridotite, troctolite and gabbro. Near the coast the mass is cut by a fault running NE.–SW. with downthrow to the SE. on which side the mass is partly covered by Old Red Sandstone. The intrusion broadens as it nears the coast and continues out to sea, where the greater part of it is to be found.