Field Testing Raman Microspectroscopic Therobarometers in Garnet

本项目将采用一种新的分析技术-共焦拉曼显微光谱-来研究其宿主矿物中天然矿物包裹体的物理特征。这些信息对于了解岩石形成的物理条件以及岩石在冷却过程中保留这些信息的程度非常重要。这项工作还将确定测量是否会受到包裹体几何形状或岩层高温的影响。如果成功的话，拉曼显微光谱学可以彻底改变对岩石形成的压力和温度的研究，这对包括火成岩，变质和成矿过程在内的各种领域都很重要。我们还可以确定是什么将岩石结合在一起，这将在材料合成科学中有广泛的应用。资金将用于支持一名新博士生的研究和培训。这项研究将用于利用博伊西州立大学的本科和研究生课程的教育机会，该大学的学生人口与其他美国大学不同。该项目的重点是严格测试石榴石石英（QuiG）气压计和石榴石锆（ZiG）温度计。三个主要问题包括：（1）石榴石中是否存在一个阈值温度，超过这个阈值温度，热拉曼光谱就失效了？(2)包裹体负压是否可靠地保存？（3）夹杂物形状是否重要？五组基本的数据将解决这些问题：（1）拉曼光谱将在一系列的压力-温度（P-T）条件下收集，看看石榴石是否可靠地编码包埋P-T条件在所有的P-T空间。ZiG的应用在鉴定是否保留了截留T中特别重要。(2)化学分区将围绕夹杂物进行调查，看看是否由膨胀或收缩夹杂物引起的压力引起的石榴石摩尔体积的化学改性。(3)将收集低磷、高温岩石的拉曼光谱，其中预期存在QuiG负压，并与预期的Pincl进行比较。(4)石英和锆石内含物中具有一系列纵横比的Pincl（拉曼峰位移）将以微米尺度进行空间映射。(5)将在石榴石中的亚毫米点上收集红外光谱，以确定OH含量和水解弱化对石榴石强度的可能影响。这些数据将测试的假设，支持应用thermoba-Raman-try和经验识别的P-T空间的区域，该方法可以应用于石榴石中的夹杂物。数据还将允许对火成岩和矿石存款形成的P-T条件进行扩展研究，而不依赖于化学或热力学模型。

This project will use a novel analytical technique - confocal Raman microspectroscopy - to investigate the physical character of natural mineral inclusions inside their host minerals. This information is important for understanding the physical conditions under which rocks form, and the degree to which rocks retain that information during cooling. This work will also identify whether measurements are biased by inclusion geometry or high temperatures of rock formation. If successful, Raman microspectroscopy could revolutionize investigations of the pressures and temperatures of rock formation, which are important to a variety of fields including igneous, metamorphic, and ore-forming processes. We may also identify what holds rocks together, which would have broad applications to materials synthesis science. Funding will support the research and training of a new PhD student. This research will be used to leverage educational opportunities in undergraduate and graduate courses at Boise State University, which reaches a different student demographic than other American universities. The central focus of this project is to critically test the Quartz-in-Garnet (QuiG) barometer and Zircon-in-Garnet (ZiG) thermometer. Three main questions include: (1) Is there a threshold temperature above which thermoba-Raman-try fails in garnet? (2) Are inclusion underpressures reliably preserved? and (3) Does inclusion shape matter? Five basic sets of data will address these questions: (1) Raman spectra will be collected over a range of pressure-temperature (P-T) conditions to see whether garnet reliably encodes entrapment P-T conditions over all P-T space. Application of ZiG is particularly important in identifying whether entrapment T's are preserved. (2) Chemical zoning will be investigated around inclusions to see whether pressures induced by expanding or contracting inclusions induce chemical modification to garnet molar volumes. (3) Raman spectra will be collected for low-P, high-T rocks, where QuiG underpressures are expected, and compared against expected Pincl. (4) Pincl (Raman peak shifts) in quartz and zircon inclusions with a range of aspect ratios will be spatially mapped at a µm scale. (5) Infrared spectra will be collected on sub-mm spots in garnet to identify OH contents and possible impact of hydrolytic weakening on garnet strength. These data will test assumptions that underpin applications of thermoba-Raman-try and empirically identify the region of P-T space over which the method can be applied to inclusions in garnet. Data will also permit expanded research into the P-T conditions of igneous and ore deposit formation, independent of chemical or thermodynamic models.