Geochemical evidence for complex magmatic plumbing during development of a continental volcanic center

The combined use of major-element compositions and experimental petrology to determine the pre-eruptive depth of equilibration, and of trace elements and isotopes to elucidate the components and mechanisms of magma-crust interaction, has enabled reconstruction of the magmatic plumbing during the initial stages of evolution of the Skye and Mull centers of the British Tertiary Volcanic Province. Early basic magmas were delayed at more than one level in the crust. Nevertheless, taken as a whole the data require that each individual batch of magma had a distinctive pre-eruption history and followed a different route through the crust. The plumbing beneath other areas of extension-related, continental basic magmatism may be equally complex.