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

马德琳·刘易斯博士获得了美国国家科学基金会EAR博士后奖学金，研究大型火山爆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在斯坦福大学与科学导师Ayla pamukpareu博士一起进行。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，人们对火山喷发对岩浆储存条件的影响程度知之甚少。火山喷发后储存的岩浆是易于移动和准备喷发，还是几乎凝固了？刘易斯博士将利用内华达州已灭绝的斯蒂尔沃特火山口复合体（SCC）来解决这些问题，该复合体暴露了火山岩和部分现已固化的岩浆储存系统。她将收集地球化学数据，计算SCC岩浆活动不同阶段的岩浆储存条件。刘易斯博士早期的研究确定了SCC岩浆活动的顺序和持续时间，她将利用这些数据来评估大型火山爆发时岩浆储存条件的变化。刘易斯博士将通过设计一个虚拟的实地考察来扩大她的工作的广泛影响，这将成为斯坦福地球实地教育的公共教育资源。此外，她还将完成STEM教育方面的培训，并志愿担任地球科学女性协会帕洛阿尔托分会的导师，以提高对攻读地球科学学位和职业的女性的保留和支持。通过对浅层硅质岩浆系统的侵入和挤压部分的研究，可以改善在火山口形成喷发后可喷发岩浆是否仍在浅层储存的不确定性。内华达的新世（~25 Ma）斯蒂尔沃特火山口复群，保存了一系列喷发前后的侵入物（岩浆历史约106年），以及两个非常大（350 km3）的爆炸性沉积物，记录了确定可喷发的熔体的快照。刘易斯博士将收集和分析喷发（挤压）和未喷发（侵入）晶体和熔融包裹体的成分，以建立矿物平衡中的岩浆储存条件（例如温度、压力、挥发性成分）。她将把这些计算出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相结合，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储层中留下了缺乏结晶性的岩浆，这表明火山系统有能力在几乎没有地震预警的情况下产生“无声”喷发。相反，如果可喷发岩浆在喷发后没有被保留在浅层，这对于将岩浆注入信号解释为即将爆发的迹象具有重要意义。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.