Collaborative Research: Bubble Trouble - Re-evaluating olivine melt inclusion barometry and trace-element geochemistry in the Cascades

合作研究：气泡麻烦 - 重新评估喀斯喀特橄榄石熔体包裹体气压和微量元素地球化学

• 批准号: 2342156
• 负责人: Penelope Wieser
• 金额: $ 29.32万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-06-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2342156&HistoricalAwards=false
• 关键词: Collaborative; Research; Bubble; Trouble; Re

Determining the depths at which molten rock (magma) is stored and processed in the crust is vital for interpretations of volcanic unrest in the lead up to eruptions and for understanding of the chemical evolution of the Earth’s continents. Despite their importance, the structure and operation of the regions which supply magma to the surface remain poorly understood. It is currently uncertain, for example, whether magma is distributed across “mush zones” spanning the entire crust or stored in distinct “magma chambers”. This project will re-evaluate magma storage depths and the origin of chemical variability in volcanic systems in the Cascades using an approach that makes use of small pockets of magma trapped within erupted crystals, termed melt inclusions. Crucially, the CO2 contents of small bubbles within these melt inclusions will be measured directly, in addition to the surrounding melt. This project will contribute to the scientific understanding of volcanism along the Cascade arc, which presents a significant hazard to society. It will also foster close collaborations and a multi-tiered, peer-to-peer mentoring structure between two early career PIs, two graduate students, and multiple undergraduate students. The grant will also support a mentoring program for scientists with disabilities and a virtual forum for academics with chronic illnesses and invisible disabilities to share their stories about adapting to fieldwork, conferences, and workshops.The volatile contents of olivine-hosted melt inclusions provide important constraints on the depths at which mafic magmas erupting in the Cascades were stored and staged prior to eruption. However, the vast majority (97%, N=410) of previously published olivine-hosted melt inclusion data from the Cascades did not measure CO2 in vapor bubble(s). Preliminary Raman analyses of N=339 Cascade vapor bubbles indicates that without these measurements, storage depths have been underestimated by factors of 2-5X. Measuring melt inclusion volatile contents while accounting for CO2 and carbonate in the vapor bubble (using in situ heating experiments) will better constrain magma storage depths in different regions of the Cascades and provide insights into any variations in storage depth along strike (perhaps due to melt H2O contents, crustal stress state, or magma flux rate). While whole-rock trace element analyses are commonly used to assess magmatic processes in both the crust and mantle, whole-rock samples are generally an amalgamation of materials assembled and modified over a great range of unknown depths. Trace element measurements from melt inclusions with known entrapment depths will better constrain assimilation and mixing processes affecting liquid compositions and can reveal where in the crust these processes occur. He isotope data from aliquots of olivine from the same samples will further constrain the extent to which crustal materials have contributed to the most mafic components. Together, these data will provide unique insights into the origins of enriched signatured of continental arc magmas. This study will also assess mantle melting conditions, the processes causing mafic magmas to stall in the crust, and other topics relevant for melt inclusion studies worldwide (e.g., identifying processes forming carbonate in vapor bubbles and testing bubble growth models). Graduate and undergraduate students will acquire skills in a wide variety of hands-on geochemical techniques, data interpretation, coding, and software development. Students will build networks by travelling to different laboratories, interacting with collaborators at academic and government institutions, and presenting their findings at professional conferences. The grant will also support the development and improvement of open-source software tools, helping the volcanological community move to data processing and modelling workflows which are findable, accessible, interoperable, and reusable (FAIR). The PIs will also co-ordinate a virtual forum with panelists and a Q&A to share the voices and experiences of individuals with invisible disabilities with a broader audience, with a focus on laboratory and field work.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.

确定在地壳中储存和加工的熔融岩石（岩浆）的深度对于在喷发前的火山动乱的解释以及理解地球化学演化持续的过程中至关重要。尽管它们的重要性，但向表面提供岩浆的区域的结构和操作仍然很糟糕。例如，目前尚不确定，例如，岩浆是分布在整个地壳上的“糊状区域”中还是存储在不同的“岩浆室”中。该项目将使用一种方法使用一种方法，该方法使用一种方法，该方法利用使用被困在爆发的晶体内的小口袋的岩浆，称为熔体夹杂物。至关重要的是，除了周围的熔体外，还将直接测量这些熔体夹杂物中小气泡的二氧化碳含量。该项目将有助于沿喀斯喀特弧线的火山主义的科学理解，这对社会构成了重大危害。它还将促进密切的合作，并在两个早期职业生涯，两个研究生和多名本科生之间进行多层，点对点的心理结构。该赠款还将支持一个针对残疾科学家的心理计划，以及一个虚拟论坛，为患有慢性疾病和无形疾病的学者分享有关适应现场工作，会议和讲习班的故事。然而，从喀斯喀特的橄榄石托管融合数据中，绝大多数（97％，n = 410）在蒸气气泡中没有测量CO2。 n = 339级联气泡的初步拉曼分析表明，如果没有这些测量，存储深度就被2-5x的因子低估了。在考虑蒸汽气泡中的二氧化碳和碳酸盐时测量熔体包含含量（使用原位加热实验）将更好地限制级联反应的不同区域的岩浆存储深度，并提供对沿打击的任何储存量变化的见解（也许是由于MELT H2O含量H2O含量，甲壳含量含量，甲壳含量，或岩浆球的速率）。虽然全摇滚痕量元件分析通常用于评估地壳和地幔中的磁过程，但全摇滚样品通常是在大量未知深度范围内组装和修改的材料的合并。来自具有已知夹层深度的熔体夹杂物的痕量元素测量将更好地限制影响液体成分的过程，并可以揭示这些过程中发生的情况。他来自相同样品的橄榄石等分试样的同位素数据将进一步限制在一起的程度，这些数据将为连续弧岩浆的丰富签名起源提供独特的见解。这项研究还将评估地幔熔融条件，导致镁铁质岩浆陷入困境的过程，以及与全球熔体包容性研究有关的其他主题（例如，识别在蒸气气泡中形成碳酸盐的过程和测试气泡生长模型）。研究生和本科生将获得各种动手地球化学技术，数据解释，编码和软件开发的技能。学生将通过前往不同的实验室，与学术和政府机构的合作者进行互动，并在专业会议上介绍他们的发现来建立网络。该赠款还将支持开源软件工具的开发和改进，帮助火山学界转向数据处理和建模工作流，这些工作流程可发现，可访问，可互操作和可重复使用（公平）。 PI还将与小组成员和问答协会协调一个虚拟论坛，以与更广泛的受众群体分享无形的残疾人的声音和经历，重点关注实验室和现场工作。该奖项反映了NSF的法定任务，并通过使用该基金会的智力功能和广泛的影响来评估Criteria criteria criteria criteria criteria被视为珍贵的支持。