The Metamorphism of the Manx Slate Series, Isle of Man

Abstract

Previous research by the present author has established the Caledonian tectonic history of the Manx Slate Series. In particular three episodes of folding (F1, F2, F3) were recognized. The present contribution describes the sequence of metamorphic textures impressed on these metasediments during this polyphase deformation.Two distinct episodes of metamorphism have affected the Manx Slate Series. A syn-tectonic F1 metamorphism produced a chloritezone alteration throughout the Island. A later F2 metamorphism was primarily responsible for the growth of small porphyroblasts of several minerals within the pre-existing F1 fabric. This second metamorphism is confined to the hinge of the large-scale F2 Manx synform and its effects are visible in an elongate belt following the middle of the Island. The emplacement of the porphyroblasts began during the F2 movement and continued into the static interval which preceded the third (F3) movement-phase. It was completed prior to the F3 deformation.