Collaborative Research: Volatiles in Aleutian Arc Magmas

合作研究：阿留申岛弧岩浆中的挥发物

• 批准号: 0609847
• 负责人: Erik Hauri
• 金额: --
• 依托单位: Carnegie Institution of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0609847&HistoricalAwards=false
• 关键词: Collaborative; Research; Volatiles; Aleutian; Arc

This project aims to determine the amount of water and carbon dioxide dissolved in magma before it erupts from active volcanoes in the Aleutian islands, Alaska. Water in particular is critical to every aspect of these magmas, from their plumbing system beneath the volcanoes, to their very origin in the subduction zone, to their gas content which fuels eruptions. Despite its primary importance, water has been determined in only a limited number of volcanic samples. The Aleutian volcanoes of Alaska offer a prime opportunity to relate water contents to existing geochemical tracers from the subduction zone, geophysical parameters of plate subduction, and geodetic measurement of magma storage depths and volcano deformation. The latter linkage will be possible through Plate Boundary Observatory installations on Augustine and Akutan volcanoes as part of the EarthScope facility. As far as we know, there are no published measurements of the water content of any Aleutian primitive magma. This project follows from a one-year pilot study funded to collect appropriate samples. We have in hand ~ 100 tephra samples from 10 Aleutian volcanoes, and we plan to collect more from Seguam volcano. Preliminary data are promising, showing among the highest water contents measured in the world in mafic arc melt inclusions ( 7 wt%) from Augustine volcano, which is currently erupting. The primary activity of the current project is to analyze melt inclusions trapped in olivine crystals for their volatile content (H2O, CO2, S, Cl,) by ion microprobe at the Carnegie Institution of Washington, and trace elements (including La, Ba, Sr, U, Th, Pb, Nb) by laser-ablation inductively coupled plasma mass spectrometry at Boston University. Another major focus will be the development of new techniques for estimating the water content of magmas from clinopyroxene crystals, one based on their rare earth element pattern, and the other on their H2O content. This project will enable a female graduate student to complete her PhD work, and will support undergraduate research at Boston University.

该项目旨在确定阿拉斯加阿留申群岛活火山喷发前岩浆中溶解的水和二氧化碳量。水对于这些岩浆的各个方面尤其至关重要，从火山下方的管道系统，到它们在俯冲带的起源，再到它们促进喷发的气体含量。尽管水非常重要，但仅在有限数量的火山样品中检测到了水。阿拉斯加的阿留申火山提供了一个绝佳的机会，可以将含水量与俯冲带的现有地球化学示踪剂、板块俯冲的地球物理参数以及岩浆储存深度和火山变形的大地测量联系起来。 后者的联系将通过作为 EarthScope 设施的一部分在奥古斯丁和阿库坦火山上安装的板块边界观测站实现。据我们所知，还没有公布任何阿留申原始岩浆含水量的测量结果。该项目是一项为期一年的试点研究的结果，该研究的资助目的是收集适当的样本。我们手头有来自 10 座阿留申火山的约 100 个火山灰样本，我们计划从塞瓜姆火山收集更多样本。 初步数据令人鼓舞，显示目前正在喷发的奥古斯丁火山的镁铁质弧熔体包裹体（7 wt%）的含水量是世界上最高的。当前项目的主要活动是通过华盛顿卡内基研究所的离子微探针分析橄榄石晶体中捕获的熔体包裹体的挥发性含量（H2O、CO2、S、Cl）以及微量元素（包括La、Ba、Sr）。 、U、Th、Pb、Nb），由波士顿大学激光烧蚀电感耦合等离子体质谱法测定。另一个主要重点是开发估算单斜辉石晶体岩浆含水量的新技术，一种基于稀土元素模式，另一种基于 H2O 含量。 该项目将使一名女研究生能够完成她的博士学位工作，并将支持波士顿大学的本科生研究。