The subducted component in island arc lavas: constraints from Be isotopes and B-Be systematics.

Although high concentrations of beryllium-10 and boron are taken as unequivocal indicators of the contribution of subducting plates, controversy persists about the processes by which material is transferred from slabs to the sources of arc magmas. Data on (10)Be/Be and B/Be ratios from four arcs suggest that the contribution from the slab is compositionally homogeneous in each arc and that subducted boron is not stored in the sub-arc mantle. The link between subduction and magma-tism at convergent margins seems to be well regulated.