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

堪察加弧提供了一个独特的机会来检验埃达克岩是由俯冲洋壳和/或下大陆地壳熔融而来的假说。堪察加弧南段由活火山和非活火山组成，火山内有地幔岩浆。北段(白令自贸区以北)火山作用包括正常的和埃达克岩的地球化学作用。埃达克岩只与科曼多尔斯基盆地年轻地壳的俯冲有关。第一个目标将是比较和对比弧南段的“正常”弧火山作用和北段的埃达克岩火山作用。埃达克岩中有几种包体，包括麻粒岩、珊瑚岩、角闪岩、角闪岩、辉石岩和辉长岩。样品中的大范围包体可能使PI能够证明埃达克岩的来源。他们将使用微探针和离子微探针来记录包体的地球化学特征和P-T条件，这将使人们有可能选择下地壳或俯冲板块作为埃达克岩的来源。

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 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.