Geochemistry of the Mariana arc (western Pacific): Source composition and processes

Abstract

The northern Mariana islands in the western Pacific form a prime example of an intra-oceanic island arc system, free from the effects of continental crustal contamination. Radiogenic (Sr, Nd, Pb, Hf) and stable (O, H, S) isotope data are presented for a suite of lavas from these islands, together with rare-earth and other trace-element compositional data for the same samples. This geochemical synthesis provides an opportunity to address a number of outstanding questions concerning oceanic arc petrogenesis, in particular the nature of the mantle source and processes occurring within this region. Much debate surrounds the origin of the commonly observed enrichments in island arc lavas relative..