9314506 Morris This study will use Be and b isotopes as tracers of the Sediment input into active margin volcanism. Concentrations of 10-Be can be compared between incoming (subducted) sediment and the volcanic, and used to determine the proportions of sediment accreted, subducted and recycled. The partitioning can then be used to determine mass fluxes at margins, to be compared with estimates derived from seismic imaging.