The origin of a Pre-Cambrian diorite-granite plutonic series from Pembrokeshire (Wales)

Abstract

SummaryA series of dioritic, granodioritic and granitic igneous rocks, of Pre-Cambrian age, is exposed near Johnston in south Pembrokeshire. Chemical analyses of representative rocks show the suite to be of calcalkaline type. An origin is suggested involving magmatic differentiation of a diorite parent magma, and the granitic rocks are compared with a granophyre of similar composition in north Pembrokeshire.