Collaborative Research: Reconstructing the geometry of magmatic plumbing systems using fluid inclusions

合作研究：利用流体包裹体重建岩浆管道系统的几何形状

• 批准号: 2217371
• 负责人: Penelope Wieser
• 金额: $ 31.1万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2217371&HistoricalAwards=false
• 关键词: Collaborative; Research; Reconstructing; geometry; magmatic

Constraining the depth at which magma feeding volcanic eruptions is stored in the crust is critical both for volcano monitoring agencies to interpret unrest signals during volcanic crises, and for our understanding of the formation of energy-critical metal deposits and the evolution of the Earth’s crust. However, popular techniques using earthquakes and ground deformation to obtain storage depths cannot be used at many potentially hazardous volcanoes which show little activity at present, or have limited monitoring networks. More widely applicable methods which measure the chemistry of erupted crystals are associated with large uncertainty. This team will investigate a powerful but under-used approach in volcanology, by measuring the densities of pockets of gas-rich fluids trapped within growing crystals, known as fluid inclusions (FI). This method has the potential to be significantly more precise and accurate, placing very tight constraints on where magma is stored in the crust. After investigating the strengths and weaknesses of depths from FIs using eruptions from Hawai’i and Canary Islands as a case study (where storage depths have been determined by other methods), magma storage depths will be investigated in a series of explosive eruptions that occurred several centuries ago at both locations where future eruptions of this type present a significant hazard. A rapid response simulation will be carried out in collaboration with Hawaiian Volcano Observatory (HVO) to determine just how quickly estimates of magma storage depths can be obtained during the next large eruptive crisis, and how this information can be used to inform decision making to mitigate societal risk. This proposal will foster close collaborations between three PIs with complimentary scientific expertise at different career levels, and support several students and a postdoc in a multi-tiered mentoring structure spanning three institutions. The team will develop and distribute synthetic and natural fluid inclusions to be used as calibration standards, and a workshop will promote collaboration and synergy between different research groups using Raman spectroscopy.This award will capitalize on recent advances in the spectral and spatial resolution of confocal Raman spectroscopy, allowing highly precise and accurate measurements of the densities of CO2-rich fluids trapped within fluid inclusions down to ~ 1 µm in size. The simple physical relationship between the density and pressure of a CO2-rich fluid means that distributions of FI densities can be converted into magma storage pressures with very small errors (~5-10%), and then magma storage depths using known crustal density profiles. First, detailed comparisons of depths obtained from FIs will be compared to published work investigating melt inclusion saturation pressures in samples from Kīlauea Volcano, Hawai’i, and Timanfaya, Canary Islands. This will permit assessment of sources of uncertainty affecting FI barometry such as decrepitation (when the inclusion explodes) using high-resolution electron backscatter diffraction (HR-EBSD), and the presence of additional volatile species (e.g., S, Cl, H) using synthetic FIs equilibrated with different fluid compositions. After determining the strengths and weaknesses of fluid inclusion barometry, new constraints will be placed on changes in magmatic plumbing during explosive to effusive transitions at Kīlauea Volcano (a significant societal hazard), evolution from shield to post-shield in the Galápagos, and from unknown samples during an eruption simulation in collaboration with HVO. Synthetic FIs with different concentrations of CO2 will be synthesized and characterized with an experimentally calibrated Raman system to distribute to laboratories around the world to use as standard reference materials for calibration of Raman Spectrometers. This will eliminate systematic offsets between densities determined in different laboratories.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.

限制岩浆喂养火山喷发的深度存储在地壳中对于火山监测机构在火山危机期间解释动乱信号以及我们对能量临界金属沉积物的形成以及地球壳的演变而言至关重要。但是，使用地震和地面变形以获得存储深度的流行技术不能在许多潜在的危险火山上使用，这些火山目前几乎没有活性，或者监测网络有限。测量爆发晶体的化学的更广泛适用的方法与较大的不确定性相关。该团队将通过测量被困在生长晶体（称为液体夹杂物（FI）的富含气体的液体）的密度来研究火山学上强大但使用不足的方法。该方法有可能明显更精确和准确，对岩浆存储在波峰中的位置非常紧密。在研究了夏威夷和金丝雀群岛的爆发作为案例研究的FIS深度的优势和缺点之后（在其他方法中确定了存储深度），将在几个世纪以前在这两种爆炸中发生的一系列爆炸性爆发中进行岩浆存储深度，这些爆发是在这两个地点发生的，在这种类型的未来爆发中都会呈现出大量的危险。将与夏威夷火山天文台（HVO）合作进行快速响应模拟，以确定在下一次大型爆发危机期间可以获得岩浆存储深度的估计的速度，以及如何使用此信息来为减轻社会风险的决策提供信息。该建议将促进三个PI之间的合作，并在不同的职业水平上提供免费的科学专业知识，并在跨越三个机构的多层心理结构中为几个学生和博士后提供支持。 The team will develop and distribute synthetic and natural fluid inclusions to be used as calibration standards, and a workshop will promote collaboration and synergy between different research groups using Raman spectroscopy.This award will capitalize on recent advances in the spectral and spatial resolution of confocal Raman spectroscopy, allowing highly precise and accurate measurements of the densities of CO2-rich fluids trapped within fluid inclusions down to ~ 1 µm尺寸。富含二氧化碳的流体的密度和压力之间的简单物理关系意味着FI密度的分布可以转换为具有很小误差（〜5-10％）的岩浆存储压力，然后使用已知的外壳密度曲线岩浆存储深度。首先，将从FIS获得的深度进行详细比较，将其与已发表的工作进行了研究，研究了夏威夷KīlaueaVolcano和Canary Islands的KīlaueaVolcano和Timanfaya的样品中的熔体纳入饱和压力。这将允许评估影响FI气压法的不确定性来源，例如使用高分辨率电子反向散射衍射（HR-EBSD），以及使用合成FIS与不同的流体成分相等的额外挥发性物种（例如S，S，CL，HR）。在确定了液体纳入气压的优势和劣势之后，将在爆炸过程中对岩浆管道变化的新限制，以爆炸性地到KīlaueaVolcano的废水过渡（一种重大的社交危险）（一种重大的社交危险），从GaláPagos的Shield到Shield的演变，以及与与未知样品的合作中的shield shield一起，以及与HVO合作期间的爆发样品。具有不同浓度CO2的合成FI将通过实验校准的拉曼系统合成并表征，以分配给世界各地的实验室，以用作标准参考材料，以校准拉曼光谱仪。这将消除在不同实验室确定的密度之间的系统偏移。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响审查标准来评估被认为是宝贵的支持。