Magmatic volatiles and degassing from the Earth

这项建议审查了影响和控制火山活动的岩浆挥发性元素的性质、来源和运输，特别是对全世界数百万人构成重大威胁的猛烈爆发的类型和规模。我的目标是使用一系列新的和新颖的工具和方法，这些工具和方法将共同推动我们对火山喷发方式、时间和原因的理解。这项研究旨在通过浅层地球系统的垂直部分来检查挥发分，从储存和向上输送挥发分的地壳条件，通过岩浆挥发分与浅层地下水和热液系统相互作用的近地表，到挥发分以火山气体形式出现的表面。研究的第一部分将使用名义上含有少量水的无水矿物(NAM)，以了解浅层地壳中岩浆水的行为，包括它的积累和损失(脱气)。将对两个系统进行详细研究，一个是玄武岩(意大利斯特龙博利)，另一个是硅质(托莱多火山口，美国新墨西哥州)。这项研究的第二个组成部分是了解潜水喷发，这通常是由岩浆气体进入浅层热液系统所驱动的。我将设计、建造并使用一种新的甲烷-二氧化碳-硫化氢混合气体仪器(这是同类仪器中的第一台)来测量甲烷/二氧化碳气体比率，它提供了一个热液和岩浆相互作用的监测器。我还将在哥斯达黎加的Rincn de la Vieja火山进行实地实验，那里的潜水喷发很常见。我将在潜水喷发之前、期间和之后进行一系列实时气体、地震和形变测量。最后，我将研究哥斯达黎加图里亚尔巴火山的一套热液角砾岩，以确定与潜水喷发和下伏的岩浆-热液系统相关的封闭和解封过程的性质。这项研究的最后一个组成部分是在近乎实时的基础上对火山羽流进行同位素表征，以评估与喷发有关的空间和时间变化。同位素体系包括二氧化碳中的13C、甲烷中的13C和水中的D和18O。在高素质人才(HQP)方面，我将总共培训13名学生(6名硕士-博士-PDF和7名学士)。在公平、多样性和包容性(EDI)方面，我的学生在过去六年中的性别平衡一直是56%的男性和44%的女性，目前是43%的男性和57%的女性，还有两名学生来自其他代表性不足的群体。我的EDI工作包括保持性别平衡、有针对性的招聘和外展。

This proposal examines the nature, origin, and transport of magmatic volatile elements in influencing and controlling volcanic activity, especially the style and size of violent explosive eruptions which pose a major threat to millions of people worldwide. My goal is to use a series of new and novel tools and approaches which together will propel our understanding of how, when, and why volcanoes erupt. The research is designed to examine volatiles through a vertical section of the shallow Earth system, moving from crustal conditions where volatiles are stored and transported upward, through the near surface where magmatic volatiles interact with shallow groundwater and hydrothermal systems, to the surface where the volatiles emerge as volcanic gas. The first component of the research will use nominally anhydrous minerals (NAM's), which contain small amounts of water, to understand the behaviour of magmatic water in the shallow crust, including its accumulation and loss (degassing). Two systems will be studied in detail, one basaltic (Stromboli, Italy) and one silicic (Toledo caldera, New Mexico, USA). The second component of the research is to understand phreatic eruptions, which are commonly driven by inputs of magmatic gas into shallow hydrothermal systems. I will design, build, and use a new CH4-CO2-H2S MultiGas instrument (first of its kind) to measure the CH4/CO2 gas ratio, which provides a monitor of hydrothermal and magmatic interactions. I will also conduct a field experiment at Rincn de la Vieja volcano in Costa Rica, where phreatic eruptions are common. I will conduct a series of real-time gas, seismic, and deformation measurements before during, and after phreatic eruptions. Last, I will study a suite of hydrothermal breccias at Turrialba volcano, Costa Rica, to determine the nature of sealing and unsealing processes associated with phreatic eruptions and the underlying magmatic-hydrothermal system. The final component of this research is to characterize volcanic plumes isotopically on a near real-time basis, to evaluate spatial and temporal changes in relation to eruptions. The isotopic systems include 13C in CO2, 13C in CH4, and D and 18O in water. In terms of highly qualified personnel (HQP), I will train a total of 13 students (6 MSc-PhD-PDF and 7 BSc). In terms of equity, diversity, and inclusion (EDI), gender balance for my students over the past six year has been 56% male and 44% female, and currently it is 43% male and 57% female, with two students from other under-represented groups. My EDI efforts include maintaining gender balance, targeted recruiting, and outreach.