Late Caledonian calc-alkaline dykes from the east coast of Aberdeenshire

Abstract

Synopsis A suite of previously undescribed microdioritic and lamprophyric dykes crop out on the east coast of Scotland, some 10–12 km south of Aberdeen, where they intrude polydeformed and metamorphosed Southern Highland Group (Dalradian) psammites. The dykes have calc-alkaline basaltic to andesitic compositions. Several contain notably high levels MgO, Cr and Ni and they are also enriched in incompatible elements. They display a range of macroscopic features indicating emplacement at high, possibly subvolcanic, levels and there is evidence for multiple intrusion. Hydrothermal alteration generated greenschist-facies epidote–actinolite and subsequent chlorite–calcite assemblages.