Collaborative Research: Quantifying the Thermal History of Crustal Magma Storage Through Crystal Records and Numerical Modeling

合作研究：通过晶体记录和数值模拟量化地壳岩浆储存的热历史

• 批准号: 1426858
• 负责人: Kari Cooper
• 金额: $ 22.99万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1426858&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; Thermal; History

The processes involved in formation and storage of magma within the Earth?s upper crust are of fundamental importance to understanding volcanoes and volcanic hazards. Previous NSF-supported research by two of the PIs showed that at Mount Hood, Oregon, only a small fraction (most likely less than 1%) of the total time that magma is stored underground is spent at high enough temperatures that would allow magma to be easily mobilized and erupted. Partial data sets for other volcanoes suggest that these conditions are widespread, but this remains to be tested. This new project will address the questions of whether magmas in general are subject to similar storage conditions as those seen at Mount Hood, and what are the fundamental controls on the processes of magma storage underneath volcanoes. The project will address these questions using geochemical measurements of crystals that grew beneath the surface and will provide information on the duration and temperature of magma storage. These results will be combined with advanced computer models of magma chambers to explore the interplay of magma addition, heat loss and changes in magma composition. In addition to contributions to the science of volcanology and geochemistry, the work will have impacts in understanding volcanic hazards ? in particular, the percentage of time that different magma bodies spend in an eruptible state (and, critically, the processes that control that percentage of time) will provide insight into the hazard represented by different volcanoes and will also provide a better context to interpret the results of seismic imaging or other remote-sensing applications. This project will contribute to training the next-generation STEM workforce by providing support for a postdoctoral researcher and three graduate students, one at each institution. At OSU and at UCD undergraduates will also take part in the research.This project will integrate observational data with numerical modeling for selected volcanic systems, to address the broader question: ?What are the thermal and physical conditions of magma storage in the Earth?s crust, and what are the primary controls on those conditions?? This project will build on our results for Mount Hood and on existing partial data sets by exploring two high-priority specific questions that pertain to the maturation of magmatic systems: 1) What is the role of volume of the shallow reservoir? How do magma storage conditions vary over erupted volumes of 1 to 10 km3? and 2) What is the role of composition? Is there a difference between the thermal history of magma storage in dacitic and rhyolitic systems? The results of this project will provide some of the first observational data on the thermal histories of magma storage, and the numerical modeling will allow us to put these results into a generalizable thermodynamic framework. These results will provide a critical, observation-based understanding of the physical conditions of magma storage, which in turn will provide a better understanding of magma reservoir processes. Ultimately we will build a framework in which to understand various aspects of crystal records such as the interpretation of mineral thermobarometry, textural information, and time scales captured by mineral zonation. The results of this project will have broad implications within the field of igneous petrology/geochemistry by providing a conceptual framework for the processes that operate within magma reservoirs ? and crucially, the time scales relevant to the different processes.

岩浆在地上的地壳内形成和存储涉及的过程对于理解火山和火山危害至关重要。两项PIS的先前由NSF支持的研究表明，在俄勒冈州的Hood Mount，只有很小的一小部分（最有可能小于1％）的岩浆存储在地下地下的时间的时间很高，这是在足够高的温度下花费的，可以轻松地动员和爆发岩浆。其他火山的部分数据集表明这些条件很普遍，但这还有待测试。这个新项目将解决岩浆一般是否符合与山山（Mount Hood）相似的存储条件的问题，以及在火山下岩浆存储过程中的基本控制是什么。该项目将使用在表面下生长的晶体的地球化学测量来解决这些问题，并提供有关岩浆存储持续时间和温度的信息。这些结果将与岩浆室的高级计算机模型相结合，以探索岩浆加成，热量损失和岩浆成分变化的相互作用。除了对火山学和地球化学科学的贡献外，这项工作还会对了解火山危害产生影响？特别是，不同岩浆体在爆发状态（批判性地控制时间百分比的过程）的时间百分比将提供对不同火山代表的危害的洞察力，并且还将提供更好的背景来解释地震成像或其他遥感应用的结果。该项目将通过为博士后研究员和三名研究生提供支持，为下一代STEM劳动力培训下一代STEM劳动力。在OSU和UCD的本科生也将参加研究。本项目将将观察数据与选定的火山系统的数值建模整合在一起，以解决更广泛的问题：？？？该项目将通过探索与岩浆系统成熟有关的两个高优先级特定的问题来建立我们的Hood Mount Hood和现有部分数据集的基础：1）浅层储层的体积的作用是什么？岩浆存储条件如何因1至10 km3的爆发量而异？ 2）构图的作用是什么？岩浆储存的热历史在dacitic和流纹岩系统中是否存在差异？该项目的结果将提供一些有关岩浆存储热历史的第一个观察数据，而数值建模将使我们能够将这些结果放入可推广的热力学框架中。这些结果将为岩浆存储的物理条件提供关键的，基于观察的理解，进而可以更好地理解岩浆储层工艺。最终，我们将建立一个框架，在其中了解晶体记录的各个方面，例如矿物热计量法的解释，纹理信息和矿物分区捕获的时间尺度。该项目的结果将通过为岩浆储层中运行的过程提供概念框架，在火成岩/地球化学领域具有广泛的影响？至关重要的是，时间尺度与不同的过程相关。