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

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在火山弧熔岩形成中的作用。该项目的主要科学目标是更好地约束弧下地幔区域的地球化学变化，以及这种变化的起源。将研究两个不同但具有可比性的俯冲系统：跨墨西哥火山带（TMVB）和中美洲弧中俯冲力更强且富含b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活动，为评估地幔的作用和限制地壳同化的影响提供了机会。该项目将分两个阶段进行：1)本科生暑期研究经历，由南佛罗里达大学和其他参与机构的学生测量来自这些套房的熔岩中B-Be-Li元素丰度；2)硕士/博士生研究来自危地马拉TMVB和关键板内火山点的熔岩的Li同位素系统。这项工作计划将培养一批本科生和研究生干部，使他们懂得利用地球化学作为研究火山弧的工具。

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.