Current research in the British Tertiary Igneous Province

Abstract

A one-day meeting on current and recent research in the British Tertiary Igneous Province, convened by Andrew Kerr, was held at the Department of Geological Sciences, University of Durham, on 1 May 1993. The meeting attracted over 50 participants, from a wide range of disciplines, including geochemistry, volcanology, petrology and structural geology. There were nine speakers and six poster presentations. After a brief welcome, by R. N. Thompson on behalf of the Durham Department, S. A. Gibson (Durham University) reviewed her work on the Little Minch Sill Complex, Skye. Field and petrographic evidence were used to show that the internal stratigraphy of the sills could be explained by multiple intrusion. Previous workers had proposed that the sill complex were fed by the same magmatic conduits as the Skye lavas. Geochemical data, however, prove that this can not be the case since the sills had been contaminated with amphibolite facies upper crust, in contrast to the predominantly lower crustal contamination of the lavas. G. R. Kitchener (Glasgow University) spoke on oxygen isotope exchange during hydrothermal alteration around the Cullin intrusion, Skye. Focusing on one lava flow, close to the margin of the intrusion, he showed how δ 18 O varied with height throughout the flow, and cast some doubt on the interpretations of δ 18 O values by previous workers on the Skye lavas. Analysis of secondary mineral separates revealed that the chlorite and the zeolites have different δ 18 O, which suggests that the hydrothermal alteration was caused by many different pulses of fluid with variable