Abstract

The Precambrian Malvernian complex of the Malvern Hills and the Johnston complex of south Pembrokeshire contain basic to acid igneous rock of similar chemical composition and of calc-alkaline type. Both complexes contain minor rock types of hybrid origin and rock which is enriched in potash. The most important difference between the two complexes is the potash-poor nature of the Johnston and the potash-rich nature of the Malvernian igneous rock. This difference may be explained by the position of the complexes in relation to the contemporaneous orogenic activity suggestive of Precambrian subduction.

First Page Preview

First page PDF preview
You do not currently have access to this article.