Collaborative Research: RUI: Diffusion studies in baddeleyite and zircon

合作研究：RUI：斜锆石和锆石的扩散研究

• 批准号: 2313679
• 负责人: Heather Watson
• 金额: $ 11.88万
• 依托单位: Union College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2313679&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Diffusion; studies

The minerals zircon (ZrSiO4) and baddeleyite (ZrO2), although present only in low concentrations in most rocks, are important phases in geochronometry (measuring ages of rocks, meteorites, and geologic events). They incorporate trace and minor elements useful as geochemical indicators. Zircons in particular are very robust mineral grains and, since they can survive many types of geological events, are some of the oldest known materials on Earth. They have preserved information about geological processes that were occurring up to 4.4 billion years ago. Understanding the diffusion (mobility of atoms) behavior of key elements inside these minerals provides major constraints on how we interpret the measured ages, and chemical signatures of rocks and ancient geological events. There has been extensive study of diffusion of several chemical elements in zircon, even if some elements have been understudied. In contrast, there is a lack of diffusion data entirely for baddeleyite, which can yield complementary information to that gained from zircon analysis. Understanding diffusion in these minerals is essential for interpreting a wide range of geochronometric data, and evaluating and interpreting the chemical and isotopic signatures retained in these minerals over geologic timeframes. The main broader impacts of this work will be a contribution of important data that can be used by a wide range of scientists in diverse, but related, fields. The project will also provide an educational experience for undergraduate students in physics, engineering, and geosciences, as well as high school students from underserved communities. The proposed experiments build on a body of work measuring diffusion of a variety of elements in accessory minerals (minerals in generally minor abundance in rocks, but which incorporate elements important as geochronometers or geochemical tracers), to obtain a more complete geochemical picture of these critical minerals. The work also continues the refinement and application of accelerator-based ion beam techniques (Rutherford Backscattering Spectroscopy and Nuclear Reaction Analysis) in diffusion studies, exploiting the superior depth resolution of these analytical methods to access the slow diffusivities characteristic of many species in these materials. With the increasing application of microanalytical techniques to analyze natural samples and access fine-scale chemical and isotopic variations, diffusion data are a critical parameter in interpreting timing of geologic events, and evaluation of past chemical environments and thermal histories. These measurements will yield critical information for interpreting isotopic ages and thermal histories for baddeleyite, a mineral of interest but for which little diffusion data currently exist. The measurements of pentavalent cation diffusion in zircon will provide information about the resistance to chemical alteration of elements potentially useful as geochemical tracers, provide insight into substitutional mechanisms and charge balance for diffusion of altervalent cations. The Xe diffusion results may have implications for better interpreting Xe isotope systematics and noble gas behaviors in terrestrial and lunar samples, and understanding histories of the early Earth and Solar System. Zirconia also has utility as a refractory and optical material, so better understanding of its properties may have technological implications. The broader impacts of this work will be as a contribution of important data that can be used by a wide range of scientists in diverse, but related, fields in the geosciences, including thermochronology, geochronology, and studies of the early Earth and Solar System. The project will involve undergraduate students in research, providing experience in preparing samples, crystal synthesis, conducting experiments, using various analytical methods, and analyzing and interpreting data and presenting at research conferences. The project will also support a community outreach effort aimed at introducing local high school students to scientific research methods and Earth science.This project is jointly funded by Petrology & Geochemistry and Division of Earth Sciences to support projects that increase research capabilities, capacity and infrastructure at a wide variety of institution types, as outlined in the GEO EMBRACE DCL.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.

矿物锆石 (ZrSiO4) 和斜锆石 (ZrO2) 虽然在大多数岩石中含量较低，但它们是地质测时学（测量岩石、陨石和地质事件的年龄）中的重要相。它们含有可用作地球化学指示剂的痕量元素和微量元素。锆石尤其是非常坚固的矿物颗粒，并且由于它们可以在多种类型的地质事件中幸存下来，因此是地球上最古老的已知材料之一。他们保存了 44 亿年前发生的地质过程的信息。了解这些矿物内部关键元素的扩散（原子迁移率）行为为我们如何解释测量的年龄以及岩石和古代地质事件的化学特征提供了主要限制。人们对锆石中几种化学元素的扩散进行了广泛的研究，即使某些元素尚未得到充分研究。相比之下，斜​​锆石完全缺乏扩散数据，而这些数据可以为锆石分析获得的信息提供补充信息。了解这些矿物的扩散对于解释各种地质测时数据以及评估和解释这些矿物在地质时间范围内保留的化学和同位素特征至关重要。这项工作的主要更广泛影响将是提供重要数据，可供不同但相关领域的广泛科学家使用。该项目还将为物理、工程和地球科学领域的本科生以及来自服务欠缺社区的高中生提供教育体验。拟议的实验建立在测量副矿物（岩石中通常含量较少的矿物，但其中包含作为地质计时仪或地球化学示踪剂的重要元素）中各种元素扩散的工作主体的基础上，以获得这些关键矿物的更完整的地球化学图像。矿物质。这项工作还继续在扩散研究中改进和应用基于加速器的离子束技术（卢瑟福背散射光谱和核反应分析），利用这些分析方法的卓越深度分辨率来了解这些材料中许多物质的缓慢扩散特性。随着微分析技术越来越多地应用于分析自然样品和获取精细化学和同位素变化，扩散数据成为解释地质事件时间以及评估过去化学环境和热历史的关键参数。这些测量将为解释斜锆石的同位素年龄和热历史提供关键信息，斜锆石是一种令人感兴趣的矿物，但目前很少有扩散数据。锆石中五价阳离子扩散的测量将提供有关可能用作地球化学示踪剂的元素的化学变化抵抗力的信息，提供对替代机制和交替阳离子扩散的电荷平衡的深入了解。氙扩散结果可能有助于更好地解释陆地和月球样品中的氙同位素系统学和惰性气体行为，以及了解早期地球和太阳系的历史。氧化锆还具有作为耐火材料和光学材料的用途，因此更好地了解其特性可能具有技术意义。这项工作的更广泛影响将是对重要数据的贡献，这些数据可供地球科学不同但相关领域的广泛科学家使用，包括热年代学、地质年代学以及早期地球和太阳系的研究。该项目将让本科生参与研究，提供制备样品、晶体合成、进行实验、使用各种分析方法、分析和解释数据以及在研究会议上发言的经验。该项目还将支持旨在向当地高中生介绍科学研究方法和地球科学的社区外展工作。该项目由岩石学与地球化学和地球科学部共同资助，以支持提高研究能力、容量和基础设施的项目正如 GEO EMBRACE DCL 中概述的那样，该奖项反映了 NSF 的法定使命，并且通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。