The Role of the Slab and the Mantle in Volcanic Arc Petrogenesis: A B-Be-Li and Li Isotope Study of Off-Axis Arc Centers in Mexico and Central America

板块和地幔在火山弧岩石成因中的作用：墨西哥和中美洲离轴弧中心的 B-Be-Li 和 Li 同位素研究

• 批准号: 0229663
• 负责人: Jeffrey Ryan
• 金额: --
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-03-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0229663&HistoricalAwards=false
• 关键词: Role; Slab; Mantle; Volcanic; Arc

RyanEAR-0229663This project will define the roles of the mantle wedge and subducting slab in generating volcanic arc lavas using B-Be-Li abundances and Li isotopes. The main scientific goal of the project is to better constrain the geochemical variability of sub-arc mantle regions, and the origins of that variation. Two different but comparable subduction systems will be studied: the Trans-Mexican Volcanic belt (TMVB) and the more vigorously subducting and B-enriched Guatemala segment of the Central American arc. These systems have low B/Be ratios and abundant off-axis volcanism, and offer the opportunity to assess the role of the mantle and constrain effects of crustal assimilation. The project will be conducted in two phases: 1) an undergraduate summer research experience, where students from the University of South Florida and other participating institutions measure B-Be-Li elemental abundances in lavas from these suites, and 2) MS/PhD student research on the Li isotope systematics of lavas from the TMVB, Guatemala, and key intraplate volcanic sites. This work plan will train a cadre of undergraduate and graduate students in the use of geochemistry as a tool in the study of volcanic arcs.

该项目将利用B-Be-Li丰度和Li同位素确定地幔楔和俯冲板片在生成火山弧熔岩中的作用。该项目的主要科学目标是更好地限制弧下地幔区域的地球化学变异性以及这种变异的起源。将研究两个不同但可比较的俯冲系统：跨墨西哥火山带（TMVB）和中美洲弧的更有力的俯冲和富含硼的危地马拉段。这些系统具有较低的B/Be比值和丰富的离轴火山作用，并提供了评估地幔作用和地壳同化的约束效应的机会。该项目将分两个阶段进行：1）本科生暑期研究经验，其中来自南佛罗里达大学和其他参与机构的学生测量这些套房熔岩中的B-Be-Li元素丰度，以及2）MS/博士生研究TMVB，危地马拉和主要板内火山遗址熔岩的Li同位素系统学。这一工作计划将培训一批本科生和研究生，使他们学会利用地球化学作为研究火山弧的工具。