EAR-PF: Measuring the Effects of Large Volcanic Eruptions on a Shallow Magma Reservoir using Microanalytical Techniques

EAR-PF：使用微分析技术测量大型火山喷发对浅层岩浆库的影响

• 批准号: 2204477
• 负责人: Madeline Lewis
• 金额: $ 18万
• 依托单位: Lewis, Madeline J
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2204477&HistoricalAwards=false
• 关键词: EAR; PF; Measuring; Effects; Large

Dr. Madeline Lewis has been awarded an NSF EAR Postdoctoral Fellowship to investigate how large volcanic eruptions affect potentially hazardous magma stored beneath the surface of the Earth. Her research, professional development, and public outreach will take place at Stanford University alongside scientific mentor Dr. Ayla Pamukçu. Volcanic centers are connected to magma storage reservoirs within Earth’s crust, yet not all magma is immediately eruptible. Magma storage conditions (pressure, temperature, and dissolved water content) strongly influence the potential for magma to erupt. However, the extent to which eruptions influence magma storage conditions is poorly understood. Is magma stored after an eruption easily mobile and primed to erupt, or is it nearly solidified? Dr. Lewis will address these questions using the extinct Stillwater Caldera Complex (SCC), Nevada, which exposes both volcanic rocks and portions of the now solidified magma storage system. She will collect geochemical data to calculate magma storage conditions during different stages of SCC magmatic activity. Dr. Lewis’s earlier research established the sequence and duration of magmatic activity in the SCC, which she will use to evaluate changes to the magma storage conditions in response to major eruptions. Dr. Lewis will expand the broader impacts of her work by designing a virtual field trip, which will be a publicly available educational resource through Stanford Earth Field Education. In addition, she will complete training in STEM education and volunteer as a mentor with the Palo Alto chapter of the Association for Women in Geoscience to improve retention and support for women pursing geoscience degrees and careers. The uncertainty surrounding whether eruptible magmas remain in shallow storage after caldera forming eruptions will be improved by investigating both the intrusive and extrusive portions of a shallow silicic magma system. The Oligocene (~25 Ma) Stillwater Caldera Complex, Nevada, preserves a sequence of pre- and post-eruptive intrusions (magmatic history of ~106 yrs), as well as two very large (350 km3) explosive deposits that record snapshots of definitively eruptible melts. Dr. Lewis will collect and analyze the compositions of erupted (extrusive) and unerupted (intrusive) crystals and melt inclusions to establish magma storage conditions (e.g., temperatures, pressures, volatile contents) from mineral equilibria. She will apply these calculated parameters to thermodynamic and diffusion-based models to estimate magma crystallinity and the residence time of eruptible magma bodies. Coupling these results with her existing high-precision geochronology data will enable tracking of reservoir conditions over the lifetime of the magma system. If eruptions are found to leave behind crystal-poor magmas in the shallow reservoir, this indicates the capacity of volcanic systems to produce “silent” eruptions with little seismic warning. Conversely, if eruptible magma is not retained shallowly after eruption, this has significant implications for interpretation of magma injection signals as an indicator of impending eruptions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

马德琳·刘易斯博士被授予NSF EAR博士后奖学金，以研究大规模火山喷发如何影响储存在地球表面下的潜在危险岩浆。她的研究、专业发展和公众宣传将与科学导师艾拉·帕慕克苏博士一起在斯坦福大学进行。火山中心与地壳内的岩浆储藏库相连，但并不是所有的岩浆都能立即喷发。岩浆储存条件(压力、温度和溶解水含量)强烈影响岩浆喷发的可能性。然而，喷发对岩浆储存条件的影响程度却鲜为人知。岩浆是在喷发后储存起来的，很容易流动并准备喷发，还是几乎固化？刘易斯博士将利用内华达州已灭绝的斯蒂尔沃特火山口杂岩(SCC)来解决这些问题，该杂岩暴露出火山岩和现已凝固的岩浆储存系统的一部分。她将收集地球化学数据，以计算SCC岩浆活动不同阶段的岩浆储存条件。刘易斯博士早些时候的研究确定了SCC岩浆活动的顺序和持续时间，她将利用这一序列和持续时间来评估因大喷发而导致的岩浆储存条件的变化。刘易斯博士将通过设计一个虚拟实地旅行来扩大她的工作的更广泛影响，该旅行将通过斯坦福地球实地教育公开提供教育资源。此外，她将完成STEM教育方面的培训，并在地球科学妇女协会帕洛阿尔托分会志愿担任导师，以改善对追求地球科学学位和职业的妇女的留住和支持。通过研究浅层硅质岩浆系统的侵入部分和喷出部分，将改善围绕火山口形成喷发后可喷发岩浆是否仍留在浅层储存中的不确定性。内华达州渐新世(~25 Ma)的Stillwater火山口杂岩保存了一系列喷发前和喷发后的侵入岩(岩浆史约106年)，以及两个非常大的(350千米)爆炸沉积物，记录了明确可喷发的熔体的快照。Lewis博士将收集和分析喷发(喷发)和未喷发(侵入)晶体和熔融包裹体的成分，以根据矿物平衡建立岩浆存储条件(例如温度、压力、挥发分含量)。她将把这些计算的参数应用到热力学和基于扩散的模型中，以估计岩浆的结晶度和可喷发岩浆体的停留时间。将这些结果与她现有的高精度地质年代学数据结合起来，将能够在岩浆系统的整个生命周期内跟踪储层条件。如果发现火山喷发在浅层水库中留下了结晶贫乏的岩浆，这表明火山系统有能力在几乎没有地震警告的情况下产生“无声的”喷发。相反，如果可喷发的岩浆在喷发后没有被浅层保留，这对于将岩浆注入信号作为即将喷发的指示器的解释具有重要意义。这一裁决反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。