COOPERATIVE RESEARCH PROGRAM: Aleutian Magnesian Andesites:Keys to Magma Generation Processes in Island Arcs

类MORB同位素特征与微量元素的极端多样性 阿留申镁安山岩的元素组成表明 这些岩石是理解岩浆的关键 阿留申岛弧的生成过程。 当镁 安山岩在阿留申群岛中部和东部很少见， 在西弧的体积上很重要， 利率很低。 镁安山岩是感兴趣的，因为它们 包括（显然）范围从几乎 纯“地幔楔”到近纯俯冲板片熔体。 这个项目是为了确定地幔楔的组成 并量化俯冲板块和地幔的贡献 楔成分更常见的岩浆岩的中央和 东弧 矿物和全岩主要成分的测定 元素、微量元素和同位素（Sr、Nd、Pb）组成 将足以描述 “正常”阿留申岩浆岩的熟悉框架。

The MORB-like isotopic character and extreme diversity of trace element compositions within ALeutian magnesian andesites suggest that these rocks are key to the understanding of magma generation processes in the Aleutian arc. While magnesian andesites are rare in the central and eastern Aleutians, they are volumetrically important in the western arc where subduction rates are low. Magnesian andesites are of interest because they include compositions that (apparently) range from melts of nearly pure "mantle wedge" to melts of nearly pure subducting slab. This project is to determine the composition of the mantle wedge and quantify the contributions of subducting slab and mantle wedge components to more common magmatic rocks of the central and eastern arc. Determinations of mineral and whole-rock major element, trace element, and isotope (Sr, Nd, Pb) compositions will be sufficient to characterize magnesian andesites within the familiar framework of "normal" Aleutian magmatic rocks.