Abstract
The Hebridean Tertiary igneous province lay 700–900 km south of a presumed plume centre, and >500 km landward of a rifted continental margin prior to opening of the northeast Atlantic. The Province includes a small number of magnesian basalts containing olivine phenocrysts with core compositions equal to, or in excess of, Fo89. Olivine-liquid equilibrium calculations suggest that these phenocrysts formed from liquids with MgO contents of 14–15 wt%, and in rare instances, 18–20 wt%. The liquidus temperatures of these magmas imply mantle potential temperatures of 1350–1460°C at distances up to 900 km from the axis of the Iceland plume. Their emplacement at c. 60 Ma implies either a long-established hotspot, or active channeling of plume material along the base of the plate towards a region undergoing considerable lower crustal extension.
- © Geological Society 1995
Please note that if you are logged into the Lyell Collection and attempt to access content that is outside of your subscription entitlement you will be presented with a new login screen. You have the option to pay to view this content if you choose. Please see the relevant links below for further assistance.