An Outline of the Structure of the Galway Granite

Abstract

AbstractRemapping of parts of the Galway granite has shown that over most of its outcrop it is a homogeneous adamellite. A steeply dipping belt of basic rocks borders the intrusion on the north where there is a reaction zone between adamellite and basic rock. A similar but gently dipping belt of basic rocks overlies the granite to the west. In the south, where there is no reaction zone, the granite intrudes and hornfelses a group of pillow lavas, greywackes, and conglomerates. The structural features of the northern border indicate that the granite has been emplaced as a diapir and radial fractures in the north-east border further indicate that the granite and its basic envelope moved upward and outward together into the Connemara schists.