EAR-PF: Resolving the tempo of edifice development and rhyolite formation in a large-caldera system, Atitlan, Guatemala

EAR-PF：解决危地马拉阿蒂特兰大型破火山口系统中建筑物发育和流纹岩形成的速度

• 批准号: 0948228
• 负责人: Heather Cunningham
• 金额: $ 17万
• 依托单位: Cunningham Heather S
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-01 至 2012-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0948228&HistoricalAwards=false
• 关键词: EAR; PF; Resolving; tempo; edifice

Dr. Heather S Cunningham has been granted the NSF Earth Sciences Postdoctoral Fellowship to carry out a research and education plan at the University of Wisconsin - Madison. The investigation aims to detail the short- and long-term trends in caldera edifice development at Atitlán Caldera, Guatemala. Selected volcanic ash and lavas representing the large silicic eruptions, associated scoria layers and cone-growth phases will be collected during a field campaign for geochemical analysis. Major and trace element data will be integrated into petrologic models to determine how large silicic magma bodies develop and if they are related by shallow-level modification processes such as fractional crystallization, magma mixing or assimilation. Isotopic data (87Sr/86Sr and 143Nd/144Nd) will be measured to support petrologic models since these isotopic ratios are distinctive to source composition. To constrain eruptive age, 40Ar/39Ar isotopes will be analyzed on phenocrysts in distinctive eruptive units. 230Th/238U disequilibrium will be measured on volcanic ash to resolve whether large silicic bodies are rapidly differentiated from a homogeneous source, such as a deep crustal hot zone, formed by the coalescence of several magma bodies or the product of crustal assimilation. By resolving the time scales and processes that lead to large-caldera eruptions and associated cone-building phases potential volcanic risk can be inferred. However, our understanding of the processes that lead to large caldera-forming eruptions is limited by the lack of recent, well-exposed deposits. Thus, the Atitlán volcanic complex is ideally suited to test conflicting models for the generation of large-volume silicic eruptions and more importantly time scales over which caldera-systems develop. In addition to the development of geochemical models, an educational exercise will be created. A Dynamic Digital Map of Atitlán Caldera will be made available to educators that will allow students hands-on access to real world data.

希瑟·坎宁安（Heather S Cunningham）博士获得了NSF地球科学博士后奖学金，以在威斯康星大学 - 麦迪逊分校执行研究和教育计划。这项投资旨在详细介绍危地马拉阿蒂特兰·瓦尔德拉（AtitlánCaldera）Caldera建筑物开发的短期和长期趋势。在现场运动进行地球化学分析期间，将收集一选的火山灰和熔岩，这些火山灰和熔岩代表大型硅爆发，相关的Scoria层和锥生长阶段。主要和微量元素数据将集成到岩石学模型中，以确定大型硅胶体的发展方式，以及它们是否通过浅层修饰过程（例如分数结晶，岩浆混合或同化）相关。同位素数据（87SR/86SR和143nd/144nd）将被测量以支持岩石学模型，因为这些同位素比与源组成不同。为了限制喷发年龄，将对独特的喷发单位的苯晶分析40AR/39AR同位素。将在火山灰上测量230/238U的二动二动物，以解决大型硅体是否与均匀的来源迅速区分，例如由几个岩浆体的合并或地壳同化产物形成的深层地壳热区。通过解决导致大型爆发的时间尺度和过程，可以推断出潜在的火山风险。但是，我们对导致大型火山口爆发的过程的理解受到缺乏近期暴露良好的沉积物的限制。这是，Atitlán火山综合体非常适合测试相互矛盾的模型，用于生成大容量的硅酮喷发，更重要的是，Caldera-Systems开发的时间尺度。除了开发地球化学模型外，还将创建一个教育练习。教育工作者将提供一张AtitlánCaldera的动态数字地图，使学生动手访问现实世界数据。