A Discussion on volcanism and the structure of the Earth - Geophysical studies relating to the Tertiary volcanic structure of the British Isles

Abstract

Gravity and magnetic survey results over the Scottish Tertiary districts are characterized by step, linear and circular anomalies relating to faulted basalts, dykes and intrusive centres. A few circular anomalies in areas offshore can be interpreted to define additional intrusive centres. Step anomalies observed in Northern Ireland indicate that normal faulting occurred after the period of igneous activity. Deep crustal structure is ill-determined; observations of anomalous magnetic time variations and enhanced heat flow appear to warrant continuation of these studies.