Field Testing Raman Microspectroscopic Therobarometers in Garnet

石榴石中拉曼显微分光测压计的现场测试

• 批准号: 1450507
• 负责人: Matthew Kohn
• 金额: $ 14.74万
• 依托单位: Boise State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1450507&HistoricalAwards=false
• 关键词: Field; Testing; Raman; Microspectroscopic; Therobarometers

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.

该项目将使用一种新型的分析技术 - 共焦拉曼微光谱法 - 研究其宿主矿物质内天然矿物质夹杂物的物理特征。该信息对于理解岩石形成的物理条件以及岩石在冷却过程中保留该信息的程度很重要。这项工作还将确定测量值是否因纳入的几何形状还是岩石形成的高温偏差。如果成功的话，拉曼的微光谱可能会彻底改变岩石形成压力和温度的投资，这对包括火成岩，变质和形成矿石的过程在内的各种领域都很重要。我们还可以确定什么将岩石融合在一起，这将在材料合成科学上广泛应用。资金将支持新的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，该课程与其他美国大学不同。该项目的主要重点是批判性测试石英（QUIG）气压计和锆石（ZIG）温度计。三个主要问题包括：（1）阈值温度以上是石榴石中的Thermoba-Raman-try失败？ （2）包容性不足是否可靠地保存？ （3）包容性形状很重要吗？五组基本数据将解决以下问题：（1）将在一系列压力温度（P-T）条件下收集拉曼光谱，以查看石榴石是否可靠地编码所有P-T空间中的夹层P-T条件。 ZIG的应用在确定是否保留夹带T的情况下尤其重要。 （2）将围绕包含物进行化学分区，以查看通过扩大或收缩夹杂物诱导的压力引起的化学修饰会导致石榴石摩尔量。 （3）将收集低P，高T岩石的拉曼光谱，预期Quig底压，并与预期的PINCL进行比较。 （4）石英和锆石夹杂物中具有一系列宽高比的PINCL（拉曼峰移）将经常以µM标度映射。 （5）将在石榴石中的亚MM斑点上收集红外光谱，以鉴定OH含量和水解削弱对石榴石强度的影响。这些数据将测试基于Thermoba-Raman-try应用的假设，并从经验上确定可以将方法应用于石榴石中的夹杂物的P-T空间区域。数据还将允许扩展到对火成岩和矿石沉积形成的P-T条件，与化学或热力学模型无关。