Experimental Insights into Crystallization of Hydrous Basaltic Andesite

火山岩中的结构和相组成保存了有关驱逐它们的过程的信息。晶相和玻璃的比例、成分和相互关系可能揭示了喷发前强烈的条件、变化的时间和与喷发上升同龄的脱挥发历史。这些参数被认为是活火山的重要监测工具，也是解释史前和遥远喷发的地质事件的重要工具。这项建议计划(1)利用动态冷却和减压实验研究镁铁质中间成分的水合岩浆中的结晶动力学、熔融包裹体捕获和同位素分馏，以及(2)调整现有的K-12科学教师专业发展计划，为夏威夷的任职前和经验丰富的教师提供所需的技能和培训，以实施对瓦胡岛、夏威夷和毛伊岛的学生实地考察。该项目将使用动态冷却和减压实验来研究镁铁质中间成分水合岩浆中的结晶动力学和熔融包裹体捕获。这些实验涉及一个复杂但在火山上看似合理的事件序列，先前没有可用的实验限制。这项研究将通过研究富挥发分的玄武岩安山岩中的结晶动力学来纠正对天然岩浆结晶认识的重大空白，实验设计将有助于与成核和相变理论的比较。

The textures and phase compositions in volcanic rocks preserve information about the processes that expel them. The proportions, compositions, and interrelationships of crystalline phases and glasses potentially reveal pre-eruptive intensive conditions, the timing of changes therein, and the devolatilization history coeval with eruptive ascent. These parameters are recognized as important monitoring tools at active volcanoes, as well as for interpreting geologic events at pre-historic and remote eruptions. This proposal presents plans to (1) investigate crystallization kinetics, melt inclusion entrapment, and isotopic fractionation in hydrous magma of mafic-intermediate composition using dynamic cooling and decompression experiments, and (2) adapt an existing professional development program for K-12 science teachers to provide Hawaii's pre-service and seasoned teachers with skills and training needed to implement student field trips to sites on Oahu, Hawaii, and Maui islands.This project will investigate crystallization kinetics and melt inclusion entrapment in hydrous magma of mafic-intermediate composition using dynamic cooling and decompression experiments. These experiments involve a complex but volcanologically plausible sequence of events for which no prior experimental constraints are available. The study will redress significant gaps in knowledge of crystallization of natural magmas by examining crystallization kinetics in volatile-rich basaltic andesite, and the experimental design will facilitate comparison with theories of nucleation and phase transformation.