RUI: Collaborative Research: The Time Scales of Magmatic Differentiation and Their Relationship to Eruptive Style

RUI：合作研究：岩浆分异的时间尺度及其与喷发方式的关系

• 批准号: 0408440
• 负责人: Karen Harpp
• 金额: $ 13.35万
• 依托单位: Colgate University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0408440&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Time; Scales

Hekla volcano in southern Iceland displays a remarkable correspondence between its style of volcanic activity and extent of petrologic evolution. Most eruptions are zoned, especially the ones that punctuate long repose, initiating with an explosive siliceous phase and ending with effusion of mafic icelandite. The pioneering work of Thorarinsson showed that the extent of differentiation at Hekla correlates with the repose between eruptions. This project is designed to study in detail the zoned products of the historical eruptions, in order to elucidate the mechanisms and timescales of differentiation. Field work will be conducted in order to collect sequences of samples from each historical eruption; because the eruptions are all historical, the minimum time for crystallization, mixing, and differentiation is well-constrained. Each of the rocks will be analyzed using modern, state of the art techniques, but the focus of this study is microanalysis of phenocryst phases, which are tracers of the liquid compositions from which they crystallized. Major and trace element zoning profiles of phenocrysts and analyses of melt inclusions will help determine the parentage of the phenocrysts, as well as the duration they have been entrained in their host magmas. Oxygen isotopic ratios of the phenocrysts and water analyses of melt inclusions record the extent to which water influences magmatic evolution. Finally, relatively short-lived actinide-series isotopic analyses of the phenocrysts will constrain their age, the amount of time they have resided in the magmatic plumbing system. In terms of broader impacts, this award will support the research endeavors of a doctoral student at the University of Idaho and six Colgate University undergraduates. The PIs have designed a plan to provide the PhD student with teaching and mentoring experience working with the undergraduates on a protracted basis. The Colgate students, in turn, will have the opportunity to participate in extended fieldwork, interact with research scientists, work on independent, focused research questions. Results will also be incorporated into both undergraduate and graduate level courses at Colgate and the University of Idaho, as well as outreach programs designed to bring hands-on science investigation to local K-12 students and community groups.

冰岛南部的赫克拉火山（Hekla Volcano）在火山活动风格与岩石学进化程度之间表现出了非凡的对应关系。大多数爆发是分区的，尤其是那些爆发长期休息，以爆炸性的硅质阶段启动，并以镁铁质冰岛的积液结束。索拉林森的开创性工作表明，Hekla的分化程度与喷发之间的休息相关。该项目旨在详细研究历史喷发的分区产品，以阐明分化的机制和时间尺度。将进行现场工作，以收集每次历史喷发的样品序列；由于喷发都是历史的，因此结晶，混合和分化的最小时间受到了良好的约束。每个岩石都将使用现代的，最先进的技术进行分析，但是这项研究的重点是对苯晶阶段的微分析，它们是它们结晶的液体成分的示踪剂。现场晶体和熔体夹杂物的分析的主要和痕量元素分区曲线将有助于确定表晶的繁殖剂，以及它们已被夹在宿主岩浆中的持续时间。熔融夹杂物的表晶和水分析的氧同位素比记录了水影响岩浆进化的程度。最后，相对较短的阳离子系列的同位素分析将限制其年龄，它们居住在岩浆管道系统中的时间。在更广泛的影响方面，该奖项将支持爱达荷大学和六个高露洁大学大学生的博士生研究。 PI设计了一项计划，为博士生提供教学和指导经验，以旷日持久地与本科生合作。高露洁的学生反过来将有机会参加扩展的野外工作，与研究科学家进行互动，研究独立，重点的研究问题。结果还将纳入高露洁和爱达荷大学的本科和研究生水平课程中，以及旨在为当地K-12学生和社区团体带来动手科学调查的外展计划。