CAREER: Measuring the tectonic and volcanic stresses* preserved in crystals

职业：测量晶体中保存的构造和火山应力*

• 批准号: 1941953
• 负责人: Kenneth Befus
• 金额: $ 53.29万
• 依托单位: Baylor University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1941953&HistoricalAwards=false
• 关键词: CAREER; Measuring; tectonic; volcanic; stresses

Earthquakes and volcanic eruptions are produced by the imbalance of geologic forces. Direct measurements of the responsible stresses are impossible because the processes are dangerous to approach or occur deep underground. Minerals are passive passengers within these dynamic environments, who then become valuable recorders of stress as they are deformed. Emergent synchrotron X-ray microdiffraction and Raman spectroscopy technologies now make it possible to quantify geologic stresses by carefully measuring changes in the atomic structure of minerals. For this CAREER award, the investigator and his team will perform fundamental research to fully explore and validate mineral and crystal deformation studies. The research program will dovetail with a 3-tiered education program that relies upon the intrinsic beauty of gemstones to capture the minds and imagination of its audience. The PI will introduce an interactive mineral display to the local museum, implement a Gems course for non-major undergraduates, and develop of a geovisualization lab for diverse graduate student research. Minerals provide an in-situ record of dynamic geologic processes because their growth and deformation respond to the surrounding environment. Synchrotron X-ray microdiffraction and Raman spectroscopy are new tools for quantifying how minerals are deformed. Synchrotron microdiffraction works by using X-ray diffraction patterns to structurally characterize minerals with micron spatial resolution. Raman spectroscopy is similarly high resolution, but instead measures strain by exploiting a mineral’s elastic response to changes in temperature or pressure. Together, these tools have the potential transform the chemistry-based high temperature geosciences into a discipline also rooted in physics and material science. The first proposed project will combine synchrotron microdiffraction with Raman spectroscopy to directly correlate crystal structure with Raman band position. Such efforts will define how crystal structure and deformation mechanisms change with changing pressure-temperature conditions. Second, pink deformation bands in rare, financially valuable diamonds will be measured using synchrotron microdiffraction. Results will identify the origin of pink color in diamonds, and importantly, constrain strain rates and stresses in the Earth’s deep lithospheric mantle. Finally, Raman thermobarometry will be performed on samples collected across a full transect of a crustal section at the Famatinian Arc, Argentina. The reliability of Raman estimates will thus be tested against critical stratigraphic constraints and independent thermobarometers. Each project provides new constraints on mineral deformation mechanisms and mechanical processes active in the subsurface. Students working on this project will be prepared for careers in academia or industry as leaders in spectroscopy, diffraction, crystallography, and geovisualization.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

地震和火山爆发是由地质力量的不平衡引起的。直接测量负应力是不可能的，因为接近或发生在地下深处的过程是危险的。矿物质是这些动态环境中的被动乘客，当它们变形时，它们就成为压力的宝贵记录者。新兴的同步加速器X射线显微衍射和拉曼光谱技术现在使人们有可能通过仔细测量矿物原子结构的变化来量化地质应力。对于这个职业奖，研究人员和他的团队将进行基础研究，以充分探索和验证矿物和晶体变形研究。该研究计划将与一个3层教育计划相吻合，该计划依赖于宝石的内在美来捕捉观众的思想和想象力。PI将向当地博物馆介绍互动矿物展示，为非专业本科生开设宝石课程，并为不同的研究生研究开发地理可视化实验室。矿物提供了动态地质过程的现场记录，因为它们的生长和变形会对周围环境作出反应。同步辐射X射线显微衍射和拉曼光谱是量化矿物变形的新工具。同步辐射显微衍射技术是利用X射线衍射图以微米级的空间分辨率对矿物进行结构表征。拉曼光谱学同样具有高分辨率，但它是通过利用矿物对温度或压力变化的弹性反应来测量应变的。总之，这些工具有可能将基于化学的高温地球科学转变为一门植根于物理学和材料科学的学科。第一个提出的项目将联合收割机同步微衍射与拉曼光谱直接关联晶体结构与拉曼带位置。这些努力将定义晶体结构和变形机制如何随着压力-温度条件的变化而变化。其次，粉红色变形带在罕见的，有经济价值的钻石将使用同步微衍射测量。结果将确定钻石中粉红色的起源，重要的是，限制地球深部岩石圈地幔的应变率和应力。最后，将对在阿根廷法马蒂尼安弧的一个地壳剖面的整个断面上收集的样品进行拉曼温压测量。拉曼估计的可靠性，因此将测试对关键的地层约束和独立的温压计。每个项目都对地下活动的矿物变形机制和机械过程提供了新的约束。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。