Collaborative Research: Residual Stress Preserved in Crystals from Volcanic Eruptions

火山喷发通过管道将岩浆从地下深处的储集层输送到地表。由于火山过程发生在地下，或者接近火山非常危险，因此很难通过直接观察来研究火山喷发的许多关键方面。在这里，一种名为同步X射线微衍射(MicroXRD)的新技术将被用来记录在火山喷发期间输送的晶体中保存的变形。显微X射线衍射仪测量了这些晶体晶格中的应变量和保持应力。火山压力很重要，因为它们控制着喷发过程，包括岩浆运动和爆炸性。解释残余应力的第一步是确定使火山晶体变形的具体过程。为此，将进行火山模拟实验以使晶体变形。利用显微X射线衍射仪对实验产物进行分析，并与天然晶体进行比较。这套实验和测量将解决火山喷发的“如何”和“为什么”。该项目开发的标准和技术将使显微X射线衍射仪能够应用于其他学科，包括构造学、气象学和材料科学。作用在岩浆上的力量控制着火山过程。因此，火山喷发产生的晶体在岩浆室、管道和侵位过程中被拉紧。同步辐射X射线微区衍射仪将通过对来自长谷和黄石火山口的一套石英、磁铁矿和锆石晶体进行亚微米空间分辨率的晶格变形分析，来量化这些应变的大小。测量应变的大小并使用晶体上的微观结构图将揭示应变是如何产生并保存在晶体中的。下一步，保存的应变将利用矿物的弹性常数和胡克定律转换为因果应力。目标是量化不同火山环境中的火山压力，并评估这些力量的力量和行动的时间尺度。微X射线衍射仪作为地质科学中的一项新兴技术具有巨大的潜力，但用于解释数据集的物理和理论基础设施有限。为此，将进行高温实验，使用无应变合成晶体模拟火山环境中的应力，并评估应变天然晶体中应力的保存情况。实验产品将通过显微X射线衍射仪进行分析，并用于识别和/或消除变形来源。

Volcanic eruptions transport magma from reservoirs deep underground to the surface through conduits. Because volcanic processes occur underground, or are very dangerous to approach, many key aspects of volcanic eruptions are difficult to study with direct observations. Here, a new technology called synchrotron X-ray micro diffraction (microXRD) will be used to document deformation preserved in crystals that were transported within volcanic eruptions. The microXRD technique measures the amount of strain and preserved stress in the crystal lattice of those crystals. Volcanic stresses are important because they control eruption processes, including magma movement and explosivity. The first step to interpreting residual stress is to identify the specific processes that strain volcanic crystals. To this end, volcanic simulation experiments will be performed to deform crystals. MicroXRD will be used to analyze the experimental products and then compare results with natural crystals. This set of experiments and measurements will address the "How" and "Why" of volcanic eruptions. The standards and techniques developed in this project will enable application of microXRD to other disciplines, including Tectonics, Meteoritics, and Materials Science. The forces that act on magmas control volcanic processes. Consequently, crystals from volcanic eruptions are strained in the magma chamber, conduit, and during emplacement. Synchrotron X-ray micro diffraction (microXRD) will be used to quantify the magnitude of those strains by analyzing crystal lattice deformation with submicron spatial resolution on a suite of quartz, magnetite, and zircon crystals from the Long Valley and Yellowstone calderas. Measuring the magnitude of strains and using microstructure maps across crystals will reveal how strain is produced and preserved in crystals. Next, the preserved strains will be translated to causal stresses using the elastic constants of the mineral and Hooke's law. The goal is to quantify volcanic stresses in different volcanic environments and assess the forces and the time scales over which those forces act. MicroXRD has exceptional potential as an emerging technology in the geological sciences, but there is limited physical and theoretical infrastructure to interpret datasets. For this reason, high-temperature experiments will be performed to simulate stresses in volcanic environments using unstrained synthetic crystals, and assess the preservation of stress in strained natural crystals. Experimental products will be analyzed by microXRD and used to identify and/or eliminate sources of deformation.