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

岩浆挥发分的出溶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，离散挥发性相(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和喷发动力学。不幸的是，喷发的火山沉积物或出土的岩浆体已经失去了大部分挥发性物质的痕迹；因此，关于活动岩浆储集层中挥发性物质迁移的时间和效率的信息仍然难以捉摸。这项拟议的研究结合了野外工作、机械模型和实验室实验，重点研究了浅层岩浆储集层中挥发物的行为，从而解决了这一知识缺口。阻碍更好地了解岩浆储藏中浅层岩浆挥发分动力学的主要挑战是：(1)不了解复杂岩浆流体(岩浆挥发分)的溶解度与压力、温度和岩浆成分的关系--因此需要新的实验--以及(2)对形成三相岩浆(由出溶的挥发分、粘性硅酸盐熔体和晶体组成的蒸气)的物理学缺乏了解。这里提出的工作不仅将填补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化学)和多相流体力学的理解。该项目将为3种熔体成分生成大量、系统的挥发分溶解度数据集；这些数据是未来扩展现有的关于长英质岩浆中挥发分和流体行为的热力学模型所必需的。该项目还开展了一项新的合作，将为博士后和研究生提供与不同机构的跨学科研究小组合作和学习的机会。私人投资机构有将不同和代表性不足的群体纳入其研究和教育方案的记录。例如，妇女和其他任职人数不足的群体的成员将参加AMNH的地球科学师生培训活动，并参加有组织的实地考察新泽西州斯特林山锌矿和博物馆。来自布朗大学的PI将参加领导力联盟SR-EIP暑期项目，该项目将第一代和代表不足的少数族裔本科生带入STEM研究。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.