RUI: Collaborative Research: Linking Small-volume Silicic Magmas to a Yellowstone Super-eruption Using a Petrochronologic Approach

黄石国家公园及其附近地区在过去的两百万年内发生了三次超级火山爆发。在超级喷发之间，成分相似的熔岩的较小渗出物喷发到表面上，但是岩浆产生的时间与超级喷发之间的关系是未知的。该项目旨在测试对比假说，黄石超级火山爆发是岩浆逐渐积累的顶点，定期被火山爆发挖掘，或者，超级火山爆发是快速岩浆生产的独立事件的结果，与较小的前体火山爆发无关。这项研究有助于我们了解大规模超级喷发的岩浆在活动火山口下产生和驻留的速度有多快，并对喷发复发和火山危险的评估产生影响。为了评估超级喷发和较小熔岩溢出之间的潜在联系，形态学，化学，测温，同位素，在210万年至130万年的超级喷发之间喷发的小体积流纹岩熔岩的年龄特征将用于确定岩浆生成和演化的时间尺度和过程。这些过程包括早期形成的火山产物的部分熔融和相关的晶体再循环，岩浆结晶和分异，以及与幔源玄武岩的混合和杂交;每个过程的相对重要性最好通过每次喷发的晶体货物来探索。具体而言，矿物锆石和透长石将从熔岩中提取，并通过各种最先进的方法进行分析，以评估小体积岩浆批次对超级喷发的贡献。间歇性喷发的年代测定将为黄石火山活动的重复间隔提供一个框架，并对可喷发岩浆的寿命问题产生影响。该奖项将允许来自威斯敏斯特学院（犹他州）的三名本科生在三年内参与实地和实验室研究，并促进这所本科生文科学院和博伊西州立大学（爱达荷州）同位素地质年代学实验室之间的知识和技术转移。合作模式将允许学生与博伊西州立大学的研究生和实验室技术人员互动，并使用威斯敏斯特学院没有的仪器进行实践研究。学生将参与数据处理，解释，并在地方和国家会议上演示，从这项研究的结果将被列入本科课程在威斯敏斯特学院，并显示在公共土地上的火山喷发现场附近的解释材料。

Yellowstone National Park and vicinity is home to three volcanic super-eruptions within the last two million years. Between super-eruptions, smaller effusions of compositionally similar lavas have erupted onto the surface, however the relationship between the timing of magma production for precursory and super-eruptions is unknown. This project seeks to test the contrasting hypotheses that Yellowstone super-eruptions are the culmination of gradual accumulation of magma that is periodically tapped by precursory eruptions, or alternatively, super-eruptions are the result of independent episodes of rapid magma production without connection to the smaller pre-cursor eruptions. This research bears on our understanding of how quickly large super-eruption volumes of magma may be generated and reside under active volcanic calderas, with implications for the assessment of eruption recurrence and volcanic hazards.To assess the potential connections between super-eruptions and smaller lava effusions, the morphological, chemical, thermometric, isotopic, and age characteristics for small volume rhyolitic lavas that erupted between the 2.1 and 1.3 million year old super-eruptions will be used to establish the timescales and processes by which magmas are generated and evolve. These processes include partial melting of earlier-formed volcanic products and associated crystal recycling, magma crystallization and differentiation, as well as mixing and hybridization with mantle-derived basalts; the relative importance of each process is best explored through the crystal cargos of each eruption. Specifically, the minerals zircon and sanidine will be extracted from the lavas and analyzed by various state-of-the-art methods to assess the contribution of small volume magma batches to the super-eruption. Dating the intermittent eruptions will provide a framework for the recurrence interval of Yellowstone volcanism and bear upon the question of lifespans of eruptable magmas. This award will allow three undergraduate students from Westminster College (Utah) to participate in field and lab based research over three years, and promote knowledge and technology transfer between this undergraduate-only liberal arts college and the Isotope Geochronology Laboratory at Boise State University (Idaho). The collaborative model will allow students to interact with graduate students and laboratory technicians at Boise State University, and conduct hands-on research with instrumentation not available at Westminster College. Students will participate in data processing, interpretation, and presentation at local and national conferences; results from this study will be included in undergraduate courses at Westminster College, and displayed as interpretive materials on public lands near the eruption sites.