The Record of Recharge, Assimilation, and Storage in the Popocatepetl Magma System from Sr Isotopes and Glass Inclusions in Phenocrysts and Experimental Petrologic Constraints

知识价值。爆炸性的硅质火山活动构成了重大的社会威胁，然而大规模的普林尼火山爆发的根本原因尚不清楚。[2]挥发性成分（如H2O、CO2、S、Cl、F）在控制岩浆储层体积和组成方面的作用，以及[3]岩浆管道系统几何形状的时间变化。对位于墨西哥城边缘的Popocatepetl火山进行了详细的研究，以评估时间变化，以及这些因素如何与过去23,000年的活动（从温度年代学记录中解密）中的喷发风格相关联。在此期间，至少发生了7次显著不同规模的普林尼火山喷发。利用电子探针、激光烧蚀ICPMS、FTIR等多种定量分析方法和实验模拟，对喷发产物进行详细研究，揭示岩浆演化和挥发性成分。更广泛的影响。该项目将支持两名博士生（其中一名是墨西哥国民）和几名本科生。该项目还将受益于与Claus Siebe博士（墨西哥国立大学墨西哥城分校）的直接合作，他在该地区通过详细的年代学工作记录了火山的喷发历史。此次合作将导致美国和墨西哥之间的重大技术转让，无疑将有助于了解该地区的火山危害。

Intellectual merit. Explosive silicic volcanism poses a major societal threat, yet the underlying causes for large Plinian eruptions remain unclear. Several contributing factors include [1] the relative contributions of different processes (e.g., fractional crystallization, recharge by new magma, interaction of magma and wall rocks) that control volumes and compositions of magma reservoirs, [2] the role of volatile components (e.g., H2O, CO2, S, Cl, F) in controlling magma properties and exsolution of a separate fluid phase, and [3] temporal variations in the geometry of magma plumbing systems. A detailed study of Popocatepetl volcano, located on the fringe of Mexico City, is proposed to evaluate temporal variations and how these factors correlate with eruptive style over the past 23,000 years of activity (as deciphered from tephrochronology records). During this period, at least seven significant Plinian eruptions of dramatically different volumes have occurred. The eruptive products will be characterized to unravel magma evolution and volatile contents, primarily via detailed study of individual phenocrysts and trapped melt inclusions therein using multiple quantitative analytical methods (electron microprobe, laser ablation ICPMS, FTIR) and experimental simulations.Broader impacts. The project will support two Ph.D. students, one of whom is a Mexican national, and several undergraduate students. The project will also benefit from direct collaboration with Dr. Claus Siebe (UNAM, Mexico city), who has documented the eruptive history of the volcano via detailed tephrochronology work in the region. This collaboration will result in significant technology transfer between the US and Mexico, and will undoubtedly contribute to understanding of volcanic hazards in the area.