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: 2216738
• 负责人: Esteban Gazel
• 金额: $ 20.96万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard 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=2216738&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.

限制火山喷发的岩浆在地壳中储存的深度对于火山监测机构解释火山危机期间的动荡信号以及我们了解能源关键金属矿床的形成和地壳的演化至关重要。然而，利用地震和地面变形来获取储存深度的流行技术不能用于许多目前几乎没有活动的潜在危险火山，或者测量喷发化学物质的更广泛适用的监测网络有限。该团队将研究火山学中一种强大但未得到充分利用的方法，即测量生长中的晶体中富含气体的流体的密度，这种方法具有潜力。为了更加精确和准确，在使用夏威夷和加那利群岛的喷发作为案例研究（其中储存深度已被确定）调查了 FI 深度的优点和缺点之后，对岩浆储存在地壳中的位置进行了非常严格的限制。通过其他方法确定），将在几个世纪前发生的一系列爆炸性喷发中调查岩浆储存深度，这些地点的未来此类喷发将带来重大危险，将与夏威夷火山合作进行快速响应模拟。观测站 (HVO) 确定在下一次大规模喷发危机期间获得岩浆储存深度的估计速度，以及如何利用这些信息为决策提供信息以减轻社会风险。该提案将促进三个 PI 之间的密切合作。该团队将在不同职业水平上拥有互补的科学专业知识，并在跨越三个机构的多层指导结构中为几名学生和一名博士后提供支持，该团队将开发和分发用作校准标准的合成和天然流体包裹体，并将举办一个研讨会来推广。使用拉曼光谱的不同研究小组之间的合作和协同作用。该奖项将利用共焦拉曼光谱在光谱和空间分辨率方面的最新进展，从而能够高精度和准确地测量困在其中的富含二氧化碳的流体的密度富含 CO2 的流体的密度和压力之间的简单物理关系意味着 FI 密度的分布可以以非常小的误差 (~5-10%) 转换为岩浆储存压力。首先，将从 FI 获得的深度的详细比较与研究夏威夷基拉韦厄火山样本中熔体包裹体饱和压力的已发表工作进行比较。加那利群岛蒂曼法亚。这将允许使用高分辨率电子背散射衍射 (HR-EBSD) 评估影响 FI 气压计的不确定性来源，例如爆裂（当夹杂物爆炸时），以及其他挥发性物质（例如，S、 Cl, H) 使用与不同流体成分平衡的合成 FI 在确定流体包裹体气压测量的优点和缺点后，将对爆炸到岩浆管道的变化施加新的约束。基拉韦厄火山（一种重大社会危害）的溢流转变、加拉帕戈斯群岛从盾构到后盾构的演变，以及与 HVO 合作进行喷发模拟期间未知样本的合成 FI 的不同浓度 CO2 的合成和表征。经过实验校准的拉曼系统分发给世界各地的实验室，用作校准拉曼光谱仪的标准参考材料，这将消除在中确定的密度之间的系统偏移。这反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Oceanic intraplate explosive eruptions fed directly from the mantle

海洋板内爆炸性喷发直接来自地幔

• DOI: 10.1073/pnas.2302093120
• 发表时间: 2023-08
• 期刊: Proceedings of the National Academy of Sciences
• 作者: DeVitre, Charlotte L.;Gazel, Esteban;Ramalho, Ricardo S.;Venugopal, Swetha;Steele;Hua, Junlin;Allison, Chelsea M.;Moore, Lowell R.;Carracedo, Juan Carlos;Monteleone, Brian
• 通讯作者: Monteleone, Brian