Collaborative Research: Degassing-based constraints on the dynamics of submarine eruptions

合作研究：基于脱气的海底喷发动力学约束

• 批准号: 1333882
• 负责人: James Gardner
• 金额: $ 9.11万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1333882&HistoricalAwards=false
• 关键词: Collaborative; Research; Degassing; based; constraints

The dynamics (ascent rate, mass eruption rate, lava flow rate, etc.) of submarine eruptions, which account for roughly 70% of the Earth's annual volcanic activity, are essentially unknown. This research will develop a degassing-based "geospeedometer" (i.e., a method for determining how fast magma moves from its magma chamber to its final resting place on the sea floor). for mid-ocean ridge basalts that will allow quantification of eruption dynamics in Earth's largest volcanic system (i.e., the mid-ocean ridge spreading centers) and help to evaluate how those dynamics impact carbon fluxes from the vast mid-ocean ridge system. A combination of detailed microanalysis of textures and volatiles in lava samples from submarine volcanic lava flows and a unique set of laboratory experiments will be used to quantify the mechanisms and rates of degassing and vesiculation in mid-ocean ridge basalts. A "geospeedometer" will be developed on the basis of those results. This geospeedometer will allow us to understand and measure flow rates of mid-ocean ridge lavas, decompression rates of the eruptions feeding them, and how flow morphologies (sheet flow vs. pillow lava) reflect eruption rate. Analyses will be focused on samples from the well mapped and comprehensively sampled 2011 eruption of Axial Volcano on the Juan de Fuca Ridge off the northwest coast of the US and Canada. Samples from this eruption will be analyzed for degassing via volatile concentrations and vesicle-size distributions of samples collected along the Axial Volcano eruptive fissures and flow paths. A central challenge will be the linking of temerature, depressurization rate, and composition to volatile concentrations and vesicle populations. Thus, a series of laboratory decompression and cooling experiments using natural, CO2-supersaturated, mid-ocean ridge basalts will be undertaken to provide insights and input parameters for model calculations, leading to the quantification of results. the 2011 eruption of Axial Volcano will serve as the test case and be used to refine models of degassing and provide the vehicle for incorporating research reesults into broadly applicable models for submarine volcanic systems. The research will also help improve estimates of carbon flux by evaluating more rigorously and quantitatively the controls on seafloor basalt degassing of CO2. Broader impacts of the research include support of graduate and undergraduate students and engagement of the investigators with K-12 STEM teachers via already plannedteacher training workshops. Research will also be incorporated into courses taught by the investigators and data will be made freely available to the public through NSF-funded data management facilities.

海底喷发的动力学（上升速率，质量喷发率，熔岩流量等）基本上未知。这项研究将开发基于脱气的“地理尺度”（即，一种确定岩浆从其岩浆室移动到海底最终休息位置的速度的方法）。 对于中海脊玄武岩，将允许在地球最大的火山系统（即近代山脊扩散中心）中量化喷发动力学，并有助于评估这些动态如何影响广阔的中洋山脊系统的碳通量。从海底火山熔岩流中的熔岩样品中的纹理和挥发物的详细微分析以及一组独特的实验室实验的组合将用于量化中洋脊中山脊中脱气和囊泡的机制和速率。将基于这些结果开发“地理尺度”。这种地理辅助器将使我们能够理解和测量中山脊熔岩的流速，喷发的减压速率以及流动形态（板流与枕头熔岩）如何反映喷发率。分析将集中在2011年在美国和加拿大西北海岸的Juan de Fuca Ridge上绘制良好和全面采样的样品。该喷发的样品将通过挥发性浓度和沿轴向火山喷发裂缝和流动路径收集的样品的囊泡大小分布进行分析。一个核心挑战将是变质，降压率和组成与挥发性浓度和囊泡群体的联系。因此，将进行一系列实验室减压和冷却实验，使用天然的二氧化碳饱和，中洋脊玄武岩，以提供模型计算的见解和输入参数，从而导致结果量化。 2011年轴向火山的喷发将用作测试案例，并用于完善脱气模型，并为将研究恢复融合到海底火山系统的广泛适用模型中提供了车辆。 这项研究还将通过更严格，更定量地评估CO2的海底玄武岩脱气，来帮助改善碳通量的估计值。这项研究的更广泛影响包括对研究生和本科生的支持以及通过已经计划的教师培训讲习班与K-12 STEM教师的调查人员的参与。 研究还将纳入调查人员教授的课程中，数据将通过NSF资助的数据管理设施免费向公众提供。