Collaborative Research: Using Trace and Ore Elements to Track Volatile Behavior and Fluid Migration within Intermediate-silicic Magma Chambers

合作研究：利用痕量元素和矿石元素追踪中硅质岩浆室内的挥发行为和流体运移

• 批准号: 1219484
• 负责人: James Webster
• 金额: $ 9.93万
• 依托单位: American Museum Natural History
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1219484&HistoricalAwards=false
• 关键词: Collaborative; Research; Using; Trace; Ore

The release and movement of magmatic volatile components, including water, carbon dioxide, sulfur, and chlorine, exert significant control on the conditions of volcanic eruptions and on the transport and deposition of potential ore metals. Many of the parameters critical for understanding these processes are invisible to direct observations because they occur up to several kilometers beneath the surface of the Earth. Researchers have suggested that other trace elements both in the magma and in crystals forming within it may be used as a proxy for interpreting volatile behavior in magma and fluids. However many of the basic variables which describe how these elements are incorporated into crystals are unknown or are in question. This study builds off observations about enrichment in different trace elements analyzed in crystals from the recent eruption (2004) of Mount St. Helens by 1) conducting hydrothermal experiments at various conditions to try to better constrain many of these questionable variables and 2) expand on the work at Mount St. Helens to look for similar elemental variations at other volcanoes, including Mt. Pinatubo, Philippines; Augustine volcano, Alaska; and Mt. Guardia, Lipari. Specifically, this work will focus on an experimental and analytical study of the elements, Li, Cu, Zn, Pb, W, and Mo. These elements are of particular interest as prior studies have suggested they are likely to be transported by volatiles (such as water, CO2, etc). The experimental results will be integrated with observations from multiple volcanic centers to fully understand the origins of these element enrichments and how this relates to the movement of volatiles in silicic magma systems and how volatile transfer influences processes of eruption and mineral deposit formation.

岩浆挥发性成分（包括水、二氧化碳、硫和氯）的释放和运动对火山喷发的条件以及潜在矿石金属的输送和沉积发挥着重要的控制作用。对于理解这些过程至关重要的许多参数对于直接观测来说是不可见的，因为它们发生在地球表面以下几公里处。 研究人员建议，岩浆和岩浆中形成的晶体中的其他微量元素可以用作解释岩浆和流体中挥发行为的代理。 然而，许多描述这些元素如何融入晶体的基本变量仍然未知或存在疑问。 这项研究建立在对圣海伦斯火山最近喷发（2004 年）的晶体中分析的不同微量元素富集的观察基础上，通过 1）在不同条件下进行热液实验，以试图更好地限制许多这些有问题的变量，2）扩展在圣海伦斯火山寻找其他火山（包括菲律宾皮纳图博火山）类似的元素变化的工作；阿拉斯加奥古斯丁火山；和利帕里瓜迪亚山。具体来说，这项工作将重点关注元素 Li、Cu、Zn、Pb、W 和 Mo 的实验和分析研究。这些元素特别令人感兴趣，因为先前的研究表明它们可能通过挥发物（例如如水、二氧化碳等）。 实验结果将与多个火山中心的观测相结合，以充分了解这些元素富集的起源，以及这与硅质岩浆系统中挥发物的运动有何关系，以及挥发物的转移如何影响喷发和矿床形成的过程。