MARGINS Post-doctoral Fellowship - Jennifer Garrison: Time-scales and mechanisms of differentiation of mafic parents to rhyodacite in Central America

摘要（0425262）- ReaganThe项目的目标是进行地球化学分析的火山岩，主要是流纹岩和流纹英安岩，从年轻的火山复合体（小于20,000岁）在萨尔瓦多萨尔瓦多和尼加拉瓜，以确定如何大量的岩浆能够产生火山口的喷发，并在什么样的时间尺度，他们演变。 伊洛潘戈，Apoyo和Apoyeque破火山口被选为本研究的基础上的年龄和体积范围，以提供一个更好的了解侵位时间俯冲带相关的岩浆在该地区。这些地点位于NSF资助的MARGINS地震带和俯冲工厂倡议的中美洲重点地点内，其目的是回答有关岩石圈生长和演变的问题，并提供信息以评估和减轻与俯冲带火山活动相关的危害。这些倡议和其他机构倡议对中美洲火山弧的重点关注导致了一些正在进行的岩石学和火山学研究。 将对这些火山杂岩的全岩样品和矿物分离物进行U、Th和Ra核素丰度、Sr-Nd-Pb-Hf和O同位素分析，目的是定量确定流纹英安岩产生和积累的时间尺度。为了帮助限制源年龄，来自熔岩的锆石将在加州大学洛杉矶分校的CAMECA离子探针上进行分析。 研究数据将与另一个实验室的主要和微量元素数据以及该地区更多镁铁质火山岩的已发表数据相结合，以了解俯冲带相关火山系统中岩浆的时间尺度和分化 这项工作的更广泛影响包括支持一名有前途的女科学家，并在清洁实验室和质谱设施的设置和使用方面对她进行培训，使用加州大学洛杉矶分校由国家科学基金会资助的共享用户离子探针设施，并使通常不合作的机构（爱荷华州大学、伍兹霍尔海洋研究所、美国地质调查局和密歇根州）之间能够开展合作。 社会影响包括扩大我们对火山爆发时间和破火山口形成的了解，这可能最终有助于制定火山灾害预测和减轻的战略。

Abstract (0425262) - ReaganThe project goal is to perform geochemical analyses on silicic igneous rocks, primarily rhyolites and rhyodacites, from young volcanic complexes (less than 20,000 years old) in El Salvador and Nicaragua to determine how the voluminous magmas capable of caldera-producing eruptions are generated and over what time-scales they evolve. Ilopango, Apoyo, and Apoyeque calderas were chosen for this study based on age and range of volumes to provide a better understanding of emplacement times for subduction zone-related magmas in the area. These sites are within the Central America focus site of the NSF-funded MARGINS Seismogenic Zone and Subduction Factory initiatives, whose purposes are to answer questions about the growth and evolution of the lithosphere and provide information to evaluate and perhaps mitigate hazards associated with subduction zone volcanism. The focused attention of these and other institutional initiatives on the Central American volcanic arc has led to a number of ongoing and complementary petrological and volcanological investigations. Whole rock samples and mineral separates from these volcanic complexes will be analyzed for U, Th, and Ra nuclide abundances, Sr-Nd-Pb-Hf and O isotopes, with the intent of determining quantitatively the time-scales of rhyodacite production and accumulation. To help constrain source ages, zircons from the lavas will be analyzed on the CAMECA ion probe at UCLA. Data from the study will then be combined with major and trace element data from another laboratory and published data for more mafic volcanic rocks from the area to understand timescales and differentiation of magmas in subduction zone-related volcanic systems Broader impacts of this work include support of a promising female scientist and training her in the set-up and use of clean lab and mass spectrometry facilities, use of an NSF-funded shared-user ion probe facility at UCLA, and enabling collaboration between institutions that do not normally work together (University of Iowa, Woods Hole Oceanographic Institute, US Geological Survey, and Michigan State). Societal implications include expanding our knowledge of volcanic eruption timing and caldera formation, which may ultimately help devise strategies for volcanic hazard prediction and mitigation.