Experimental Insights into Crystallization of Hydrous Basaltic Andesite

火山岩的结构和相组成保存了它们形成过程的信息。晶体相和玻璃的比例、组成和相互关系潜在地揭示了喷发前的密集条件、其中变化的时间以及与喷发上升同时发生的脱挥发历史。这些参数被认为是活火山的重要监测工具，也是解释史前和偏远火山喷发的地质事件的重要工具。该提案提出了以下计划：(1)利用动态冷却和减压实验研究镁基-中间成分含水岩浆的结晶动力学、熔体包裹体包裹和同位素分选；(2)修改现有的K-12科学教师专业发展计划，为夏威夷的职前教师和经验丰富的教师提供必要的技能和培训，以实施学生到瓦胡岛、夏威夷和毛伊岛的实地考察。本项目将利用动态冷却和减压实验研究镁基-中间成分含水岩浆的结晶动力学和熔体包裹体包裹。这些实验涉及一个复杂但在火山学上似乎合理的事件序列，没有事先的实验约束。该研究将通过研究富含挥发物的玄武岩安山岩的结晶动力学来弥补天然岩浆结晶知识的重大空白，并且实验设计将有助于与成核和相变理论进行比较。

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.