Collaborative Research: RUI: The Effects of CO2-H2O Fluids on the Deformation of Quartzite and Marble in the EJB Aureole, California

合作研究：RUI：CO2-H2O 流体对加利福尼亚州 EJB Aureole 中石英岩和大理石变形的影响

• 批准号: 0711299
• 负责人: Sven Morgan
• 金额: $ 12.03万
• 依托单位: Central Michigan University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0711299&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Effects; CO2

It has been shown by laboratory studies that water has a drastic effect on the rheology of rocks, specifically influencing rock strength, strain rates, and recovery mechanisms. In this project, the a research team from Central Michigan University and the University of Missouri, Columbia, will use a natural laboratory approach to investigate the direct effects of variable fluid composition on naturally deformed quartzites and marbles. The team will examine the influence of variable water-carbon dioxide fluids on deformation and recrystallization of these rocks in the aureole surrounding the Eureka Valley-Joshua Flat-Beer Creek composite pluton in the White Mountains of California where a period of intense high temperature deformation was associated with pluton emplacement. The goal of the project is to determine how the rheology of the wall rocks, influenced by fluids, affected the emplacement and space-making processes of mid-crustal plutons, and from a broader perspective, to assess how fluids affect the deformation and the strength of the continental lithosphere. The constrained environment of the Eureka Valley-Joshua Flat-Beer Creek pluton aureole provides an opportunity to compliment the current understanding of rock deformation and recrystallization from laboratory experiments that must be done at much higher strain rates than are seen in nature. The study will integrate field, microstructural, petrologic and geochemical work to determine the influence of variable amount of water and fluid composition on deformation of quartzites and related marbles. The fieldwork will provide the context for the study and recognize areas of high and low strain. Electron backscatter diffraction, universal stage, and grain shape analyses will be used to determine the deformation and recovery mechanisms of the quartzites and marbles. Mineralogy and stable isotope ratios in the rocks will indicate the compositions of fluids that flowed through the individual lithologies, while analysis of fluid inclusions will directly show fluid compositions.The rate of deformation of the Earth's lithosphere controls its topographic features. Laboratory experiments have shown that water in particular promotes the deformation and recrystallization of rocks at high temperatures and pressures experienced by the deep continental crust. Thus, while it is generally recognized that in the lower continental crust rocks are ductile, the temperature at which they become ductile is influenced by the composition of fluids that may exist in the rocks. In the upper crust, the deformation of rocks around magma plutons will also be influenced by fluid compositions. The application of laboratory experiments to deformation of the continental crust is sometimes difficult, however, because of the vastly different time scales at which deformation occurs in the laboratory and the crust and because laboratory experiments do not reproduce the complex deformation environments seen in nature. This project will evaluate the deformation and recrystallization of crustal lithologies in the natural laboratory of the metamorphic aureole of a pluton in the White Mountains of California. The rocks in the metamorphic aureole have experienced various degrees of deformation and recrystallization that appear to have been influenced by fluids with variable proportions of water and carbon dioxide. Field work and several sophisticated techniques will be used to determine the deformation and recrystallization mechanisms of rocks in the metamorphic aureole and the compositions of fluids that flowed through the rocks. This work will provide a better understanding of factors that influence rock deformation at rates that are controlled by tectonic forces and magma ascent through the crust.

实验室研究已经表明，水对岩石的流变性有着巨大的影响，特别是影响岩石强度、应变速率和恢复机制。 在这个项目中，来自中密歇根大学和密苏里州大学哥伦比亚分校的一个研究小组将使用自然实验室方法来调查可变流体成分对自然变形石英岩和大理石的直接影响。该小组将研究可变的水-二氧化碳流体对加州白色山脉尤里卡山谷-乔舒亚弗拉特-比尔溪复合岩体周围光环中这些岩石的变形和重结晶的影响，在那里，一段时期的强烈高温变形与岩体侵位有关。该项目的目标是确定受流体影响的围岩流变学如何影响中地壳岩体的就位和形成空间的过程，并从更广泛的角度评估流体如何影响大陆岩石圈的变形和强度。尤里卡谷约书亚平坦比尔溪岩体光环的约束环境提供了一个机会，以恭维目前的岩石变形和重结晶的实验室实验，必须在更高的应变速率比在自然界中看到的理解。这项研究将综合实地、显微构造、岩石学和地球化学工作，以确定水量和流体成分的变化对石英岩和相关大理石变形的影响。实地工作将为研究提供背景，并识别高应变和低应变的区域。电子背散射衍射，通用阶段，和晶粒形状分析将用于确定石英岩和大理石的变形和恢复机制。岩石中的矿物学和稳定同位素比值将指示流经单个岩性的流体的组成，而流体包裹体分析将直接显示流体组成。地球岩石圈的变形速率控制其地形特征。实验室实验表明，在大陆地壳深部经历的高温高压下，水尤其会促进岩石的变形和重结晶。因此，虽然人们普遍认为，在下大陆地壳岩石是韧性的，温度时，他们成为韧性的影响，可能存在于岩石中的流体的组成。在上地壳中，岩浆岩体周围岩石的变形也会受到流体成分的影响。然而，由于实验室和地壳中发生变形的时间尺度差别很大，而且实验室实验无法再现自然界中所见的复杂变形环境，因此，将实验室实验应用于大陆地壳变形有时是困难的。本项目将在加州白色山脉一个岩体的变质晕的天然实验室中评价地壳岩性的变形和重结晶。变质晕中的岩石经历了不同程度的变形和重结晶，似乎受到了水和二氧化碳比例不同的流体的影响。将利用实地工作和若干尖端技术来确定变质晕中岩石的变形和重结晶机制以及流过岩石的流体的成分。这项工作将提供一个更好的理解的因素，影响岩石变形的速度控制的构造力和岩浆上升通过地壳。