 She identified that the Soufrière Hills magma contained amphibole, quartz, plagioclase, pyroxene, magnetite and ilmenite at pressures of 115 to 130 Megapascals.She worked at the University of California, Berkeley and University of Geneva, as well as serving as a duty scientist at the Montserrat Volcano Observatory.In 1999 Barclay was appointed to the University of East Anglia.