Collaborative Research: Tracking the Exsolution and Migration of Volatiles in Shallow Magma Reservoirs

岩浆挥发物的析出和运移对岩浆的化学和物理演化有着深远的影响。更具体地说，离散挥发相（气泡）的存在影响了各种金属进出岩浆体的运输，从而导致矿床的形成，并控制了喷发的可能性以及喷发动力学。不幸的是，喷发的火山沉积物或挖掘出来的岩浆体已经失去了大部分挥发性物质的踪迹；因此，关于活动岩浆储层的溶蚀时间和挥发性运移效率的信息仍然难以捉摸。提出的研究通过结合现场工作、力学模型和实验室实验来解决这一知识空白，重点关注浅层岩浆储层中挥发物的行为。阻碍更好地了解岩浆储层中浅层岩浆挥发物动力学的主要挑战是：(1)缺乏对复杂岩浆流体（岩浆挥发物）的溶解度对压力、温度和岩浆成分的依赖性的了解，因此需要进行新的实验；(2)缺乏对变形的三相岩浆（由溶解的挥发物、粘性硅酸盐熔体和晶体组成的蒸汽）的物理理解。这里提出的工作不仅将解决上述岩浆系统知识的空白，还将推动我们对复杂岩浆流体热力学（直接应用于金属成矿流体的化学）和多相流体力学的理解。该项目将生成3种熔体成分的大量、系统的挥发溶解度数据集；这些数据对于将来扩展现有的关于长英质岩浆挥发性和流体行为的热力学模型是必需的。该项目还有一个新的合作项目，将为博士后和研究生提供一个与不同机构的跨学科研究团队合作和学习的机会。私人学院在其研究和教育项目中有将不同和代表性不足的群体纳入其中的记录。例如，妇女和其他代表性不足的群体的成员将参加美国国家自然研究所的地球科学师生培训活动，并参加有组织的对新泽西州斯特林山锌矿和博物馆的实地考察。布朗大学的pi将参加领导联盟SR-EIP暑期项目，该项目将第一代和代表性不足的少数族裔本科生带入STEM研究。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。

The exsolution and migration of magmatic volatiles have a profound influence over the chemical and physical evolution of magmas. More specifically, the presence of a discrete volatile phase (gas bubbles) affects the transport of a wide variety of metals in and out of magma bodies leading to ore deposit formation and controls the likelihood of an eruption as well as eruption dynamics. Unfortunately, erupted volcanic deposits or exhumed magma bodies have lost most traces of their volatile cargo; so, information about the timing of exsolution and the efficiency of volatile migration in active magma reservoir remain therefore elusive. The proposed study addresses this gap in knowledge with a combination of field work, mechanical models and laboratory experiments focusing on the behavior of volatiles in shallow magma reservoirs. The main challenges that prevent a better understanding of the dynamics of shallow magmatic volatiles in magma reservoirs are (1) the lack of understanding of the dependence of the solubility of complex magmatic fluids (magmatic volatiles) on pressure, temperature and magma composition -thus requiring new experiments- and (2) the lack of understanding of the physics of deforming three-phase magmas (vapors composed of exsolved volatiles, viscous silicate melts and crystals). The work proposed here will not only address the gap in knowledge of magmatic systems described above, it will also push the boundaries of our understanding of the thermodynamics of complex magmatic fluids (with direct application to the chemistry of metallic ore-forming fluids), and multiphase fluid mechanics. This project will generate a massive, systematic volatile solubility data set for 3 melt compositions; these data are required for future expansion of extant thermodynamic models on volatile and fluid behavior in felsic magmas. This project also features a new collaboration which will provide a postdoc and a graduate student with an opportunity to work with and learn from an interdisciplinary research team at different institutions. The PIs have a record of incorporating diverse and under-represented groups within their research and education programs. For example, women and members of other under-represented groups will participate in Earth science teacher-student training events at the AMNH and in an organized field excursion to the Sterling Hill Zinc Mine and Museum, NJ. The PIs from Brown University will participate in the Leadership Alliance SR-EIP summer program, which brings 1st generation and under-represented minorities undergrads to STEM research.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.