Investigating the volatile evolution and decompression rate of high-intensity basaltic eruptions

研究高强度玄武岩喷发的挥发演化和减压率

• 批准号: 2318614
• 负责人: Esteban Gazel
• 金额: $ 34.83万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2318614&HistoricalAwards=false
• 关键词: Investigating; volatile; evolution; decompression; rate

Knowledge of the driving factors in generating highly explosive volcanic eruptions has been mostly focused on felsic (evolved melts high in silica) eruptions. Nevertheless, mafic (less evolved melts high in magnesium) eruptions of similar explosivity intensity have yet to be studied, even though mafic volcanism is the most common type of volcanic activity on Earth, and they could also trigger devastating societal and environmental impacts. This project aims to improve understanding of mafic volcanism by reconstructing the chemical evolution and volatile budgets from melt inclusions, small droplets of melt trapped during crystal growth that preserved the history of the most explosive mafic eruptions in the geologic record. This study will provide insights on the timescales over which mafic magmas ascend to erupt explosively, which can be used to inform eruption response efforts and forecasts. The research team will collaborate with the U.S. Geological Survey’s Hawaiian Volcanic Observatory (HVO-USGS) to disseminate knowledge among global volcanic monitoring and risk assessment agencies. The work will also broaden the global use of geochemical techniques in volcano monitoring and response by supporting a module in the Center for the Study of Active Volcanoes (CSAV) summer course. This project will support graduate and undergraduate students through training in different micro-analytical techniques at Cornell and HVO, and their applications to understand eruptions. Results from this project will be incorporated into Earth Materials and Volcanology courses at Cornell. Finally, this project will enhance the infrastructure for research and education by establishing collaborations between Cornell University, HVO-USGS, the University of Manchester, LDEO-Columbia University, the University of Auckland, Caltech, and Syracuse University.High-intensity explosive eruptions (sub-Plinian, Plinian, and ultra-Plinian, with a volcanic explosivity index of 6+) result in global environmental effects and have great potential for devastating societal impacts. Among these eruptions, mafic eruptions are the least studied and represent a critical end-member urgently needing further investigation. Of particular interest is the determination of their magma decompression rates (dP/dt), as this parameter plays a crucial role in setting the style of volcanism in the eruption dynamics for basaltic magmas. This project will study the volatile evolution and decompression of basaltic Plinian to sub-Plinian eruptions. These eruptions represent some of basaltic volcanism's most catastrophic and least understood end-members. Reconstructing their eruption histories will address the following questions: 1) What is the record of pre-eruptive conditions and degassing that characterizes basaltic Plinian eruptions? To accurately constrain magmatic conditions, the evolution of volatile saturation and degassing before and during the eruption, and decompression pathways, the team will use olivine-hosted MIs. 2) What are the decompression rates of basaltic Plinian eruptions? Estimates of magma decompression rates for the proposed eruption case studies need to be improved or constrained indirectly using numerical models, experiments, and crystal textures. This work aims to complement the volatile evolution history with two petrological tools based on time-dependent chemical reactions: volatile diffusion across olivine-hosted embayments and concentration gradients of H+ in olivine crystals. 3) Do high-intensity mafic eruptions display a correlation between decompression rate and eruption magnitude? Current data suggest low and mildly explosive basaltic eruptions show a clear positive correlation between decompression rate and eruption magnitude. However, these data are not available for higher-magnitude eruptions. This project will answer this question with new decompression rates studies supplemented with literature data.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.

关于产生高爆炸性火山喷发的驱动因素的知识主要集中在长英质（高硅含量的演化熔体）喷发上。然而，类似爆炸强度的镁铁质（镁含量高的低演化熔体）喷发尚未得到研究，尽管镁铁质火山活动是地球上最常见的火山活动类型，它们也可能引发毁灭性的社会和环境影响。该项目旨在通过重建熔融包裹体的化学演化和挥发性预算来提高对镁铁质火山作用的理解，熔融包裹体是在晶体生长过程中捕获的小熔滴，保留了地质记录中最具爆炸性的镁铁质火山爆发的历史。这项研究将提供有关镁铁质岩浆上升到爆发的时间尺度的见解，这可以用于通知喷发响应工作和预测。该研究小组将与美国地质调查局夏威夷火山观测站（HVO-USGS）合作，在全球火山监测和风险评估机构中传播知识。这项工作还将通过支持活火山研究中心夏季课程中的一个模块，扩大地球化学技术在火山监测和应对方面的全球应用。该项目将支持研究生和本科生通过在康奈尔大学和HVO不同的微观分析技术的培训，以及他们的应用，以了解喷发。该项目的成果将被纳入康奈尔大学的地球材料和火山学课程。最后，该项目将通过在康奈尔大学、HVO-USGS、曼彻斯特大学、LDEO-哥伦比亚大学、奥克兰大学、加州理工学院和锡拉丘兹大学之间建立合作，加强研究和教育基础设施。（次普林尼、普林尼和超普林尼，火山爆发指数为6+）造成全球环境影响，并极有可能造成毁灭性的社会影响。在这些喷发中，镁铁质喷发是研究最少的，代表了一个关键的端元迫切需要进一步调查。特别感兴趣的是，他们的岩浆减压率（dP/dt）的测定，因为这个参数起着至关重要的作用，在玄武岩岩浆喷发动力学的火山作用的风格。本项目将研究玄武质普林尼期至次普林尼期喷发的挥发性演化和减压。这些喷发代表了玄武岩火山作用中最具灾难性和最不为人所知的端元。重建他们的喷发历史将解决以下问题：1）什么是喷发前的条件和脱气的特点玄武普林尼火山喷发的记录？为了准确地限制岩浆条件，火山爆发前和喷发期间挥发性饱和和脱气的演变，以及减压途径，研究小组将使用橄榄石托管的MI。2)玄武质普林尼期喷发的减压速率是多少？岩浆减压率的估计建议喷发的案例研究需要改进或约束间接使用数值模型，实验和晶体结构。这项工作的目的是补充挥发性的演化历史与两个岩石学工具的基础上，随时间变化的化学反应：挥发性扩散整个橄榄石托管海湾和浓度梯度的H+在橄榄石晶体。3)高强度镁铁质喷发显示减压率和喷发强度之间的相关性吗？目前的数据表明，低和轻度爆炸玄武岩喷发减压率和喷发规模之间存在明显的正相关关系。然而，这些数据无法用于更高级别的喷发。该项目将通过新的减压率研究和文献数据来回答这个问题。该奖项反映了NSF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。

项目成果

Laser heating effect on Raman analysis of CO2 co-existing as liquid and vapor in olivine-hosted melt inclusion bubbles

激光加热效应对橄榄石熔体包裹体气泡中液态和气态共存 CO2 拉曼分析的影响

• DOI: 10.30909/vol.06.02.201219
• 发表时间: 2023
• 期刊: Volcanica
• 作者: DeVitre, Charlotte L.;Dayton, Kyle;Gazel, Esteban;Pamukçu, Ayla;Gaetani, Glenn;Wieser, Penny E.
• 通讯作者: Wieser, Penny E.