Collaborative Research: Arc Volcanism in Kamchatka, U.S.S.R., through both Partial Melting of the Mantle Wedge and Subducted Slab: A Geochemical and Tectonic Approach

点击翻译按钮获取中文摘要

Kamchatka arc provides a unique opportunity to test the hypothesis that adakites are derived from the melting of subducted oceanic crust and/or lower continental crust. The southern section of the Kamchatka arc consists of active and inactive volcanoes with mantle derived magmas. The northern section (north of the Bering F.Z.) volcanism includes both normal and adakite geochemistries. The adakites are associated only with the subduction of the young crust in the Komandorsky basin. The first objective will be to compare and contrast "normal" arc volcanism in the southern section of the arc with the adakite volcanism found in the northern section. There are several xenoliths found among the adakites including granulites, cortlandites, amphibolites, hornblendites, pyroxenites, and gabbros. The large range of xenoliths in the samples may enable the PIs to document the source of the adakites. They will use a microprobe and an ion microprobe to document the geochemical signatures and P-T conditions of the xenoliths which should make it possible to choose between the lower crust or subducted slab as the source of the adakites.