Alkaline igneous rocks: a review symposium

Abstract

Report of a meeting of the Volcanic Studies Group of the Geological Society held at Heriot-Watt University, Edinburgh, on 13–16 September 1984. The organizers were Dr J. G. Fitton and Professor B. G. J. Upton. The papers presented at the symposium will be published as a Special Publication of the Geological Society. The symposium was held to mark the passage of 10 years since the publication of the review volume The Alkaline Rocks, edited by Henning Sørensen, who opened the meeting and presented a summary of the proceedings at the end. Two and a half days were devoted to the presentation of papers and one and a half days to local field excursions. The meeting was well attended with about 150 delegates, 60 of whom were from overseas. In addition to the 30 papers presented there were several poster displays. Presentations included specific case histories of individual alkaline volcanoes and regional reviews of alkaline rock occurrences in both continental and oceanic settings. Reviews were presented of the occurrence of various alkaline associations, including kimberlite, lamproite, lamprophyre, nephelinite, and carbonatite, and the impact of isotopic and experimental petrological studies on the subject was emphasized. Alkaline magmas are characterized by high concentrations of large-ion lithophile elements (LILE). The causes of this have been the subject of debate over the past decade, with metasomatic enrichment of the mantle source before melting being a currently favoured hypothesis. Studies of mantle enrichment and melting processes are clearly essential to an understanding of alkaline magma