RUI: How is the Granite Melt Flow Network Recorded in Migmatites and by Associated Granite Plutons?

RUI：混合岩和相关花岗岩深成体中的花岗岩熔体流网络是如何记录的？

• 批准号: 0510726
• 负责人: Gary Solar
• 金额: --
• 依托单位: SUNY College at Buffalo
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0510726&HistoricalAwards=false
• 关键词: RUI; How; Granite; Melt; Flow

Because melt transfer affects the thermal and rheological behavior of the crust during orogenesis, it has become important to understand the mechanism by which melt is transferred from source to sink. This record is in the geometry, petrography, geochronology and geochemistry of granites associated with migmatites at all scales (matrix-mineral to pluton scales). Within migmatites the geometry of smaller-volume granites may have recorded a quasi-steady network of melt migration, partly controlled by deformation during melt production. Although the geometry of these bodies may be fragments of the full-flow network due to periodic closing and opening of conduits, some vein-like bodies may travel as a whole during deformation. The presence of granite in structurally controlled sites suggests melt flow during deformation, as is supported by experimental data. This work is focused upon a complete interdisciplinary approach to the question of orogenic granite melt flow. The 3-D documentation the geometry of migmatitic structures (e.g., leucosomes and smaller-volume granite bodies) and associated plutons is essential information as these data amount to some sort of plumbing, with migmatitic fabrics/structures as the conduits. Despite the possibility that this geometry may be fragmentary or composite, the base of understanding can come only from this detailed analysis. Subsequent geochronological and geochemical data is placed in a solid, meaningful framework. Work is focused on single large exposures, small sets of closely-spaced outcrops and along a series of transects in western Maine, and continues into in New Hampshire. The outcome of the research is the better understanding of melt-transit through the crust in orogens, as well as the capacity to use the results to better constrain regional tectonics. We approach this outcome through connection between detailed (labor-intensive) mesoscale and microscale observation of key exposures. The study fundamentally incorporates several small-scale field and laboratory studies that are performed by many workers, operating simultaneously within a given region. Each part of the study, therefore, sums to a larger-scale project aimed at a singular goal. Therefore, the work is perfectly suited for undergraduate student projects that necessarily operate on single-semester to single-year time scales. An important impact of this study is the involvement of a team of undergraduate students from both PIs' institutions. Research experiences take the form of year-long Honors Theses and one-semester Independent Studies with foci related to distinct parts of the overall project. The focus on team participation in a larger project allows students to reap the benefit of being invested in a significant piece of high-level science. This allows for teamwork while conducting independent work, and seeing how individual projects are important components in the larger effort. Some students will gain additional experience by visiting other facilities in order to perform some of the lab work. The collaborative nature supports exchanging ideas and learning from one another.

由于熔体转移影响造山过程中地壳的热流变行为，因此了解熔体从源转移到汇的机制变得非常重要。这个记录是在所有尺度（基质矿物到岩体尺度）上与混杂岩有关的花岗岩的几何、岩石学、地质年代学和地球化学。在混岩中，体积较小的花岗岩的几何形状可能记录了一个准稳定的熔体迁移网络，部分受熔体产生过程中的变形控制。虽然这些体的几何形状可能是由于管道的周期性关闭和打开而形成的全流网络的碎片，但有些脉状体在变形过程中可能作为一个整体移动。花岗岩在构造控制区域的存在表明在变形过程中熔体流动，实验数据支持了这一点。这项工作的重点是一个完整的跨学科的方法来解决造山花岗岩熔融流的问题。3-D文件记录了混合岩构造（例如，白色体和小体积花岗岩体）和相关岩体的几何形状，这些数据相当于某种管道，以混合岩结构/结构作为管道。尽管这种几何形状可能是零碎的或复合的，但理解的基础只能来自这种详细的分析。随后的地质年代学和地球化学数据被放置在一个坚实的、有意义的框架中。工作集中在单一的大曝光，小组紧密间隔的露头，沿着缅因州西部的一系列横断面，并继续到新罕布什尔州。这项研究的结果是更好地了解造山带中地壳的融化运输，以及利用这些结果更好地约束区域构造的能力。我们通过对关键暴露的详细（劳动密集型）中尺度和微观尺度观察之间的联系来接近这一结果。这项研究基本上包括由许多工作人员在特定区域内同时进行的几项小规模实地和实验室研究。因此，研究的每一部分都是一个针对单一目标的大型项目。因此，这项工作非常适合本科生的项目，这些项目必须在一个学期到一年的时间尺度上进行。这项研究的一个重要影响是来自两所学院的本科生团队的参与。研究经历采取为期一年的荣誉论文和一学期的独立研究的形式，重点是与整个项目的不同部分相关。在一个更大的项目中，注重团队参与，使学生能够从投资于一个重要的高水平科学领域中获益。这允许在进行独立工作的同时进行团队合作，并看到单个项目如何在更大的工作中成为重要的组成部分。一些学生将通过参观其他设施来完成一些实验室工作来获得额外的经验。协作性支持彼此交换想法和相互学习。