Geochronology of Inner Solar System Materials Down to Atom Scale

内太阳系材料的地质年代学直至原子尺度

• 批准号: RGPIN-2014-05823
• 负责人: Moser, Desmond
• 金额: $ 3.13万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611866
• 关键词: Geochronology; Inner; Solar; System; Materials

The recovery of time information from natural materials is essential to understanding the history of planets and the exploration of their mineral resources, and microcrystals of minerals such as zircon are an amazing tool for this. They are the ultimate survivor crystals and contain trace amounts of Uranium that can be used to date volcanic, tectonic, ore-forming, and impact events throughout solar system history. During tenure of my current Discovery Grant I have built a nationally unique electron nanobeam laboratory (the "ZAPLab") and established a new approach to geochronology using state-of-the-art electron microscopy. This allows us to find these microcrystals in places they've not previously been recognized, and to measure their growth history as well as signatures of origin and disturbance by events such as large meteorite impacts. My team combines this ‘structural time’ information with the chemical record of time preserved as ratios of radioactive isotopes of Uranium and the stable daughter Lead atoms. My program has so far yielded breakthrough results manifest most recently in our publication in the journal Nature in which we solved a decades-old geochronology puzzle to reveal that the most common Martian meteorites originally formed on the flanks of young Martian supervolcanoes rather than as 4 billion year old crust (Moser et al. 2013a). Many more discoveries are anticipated owing to our discovery in partnership with meteorite archivists and collectors of a large suite of other dating minerals in inner solar system meteorites ranging from the Moon to the Asteroid Belt. The next five years will also see my team establish a new geochronology approach using the Atom Probe, a recently developed instrument for materials science that allows us to image the atoms in crystals in three dimensions. We will improve on our early results that show it is possible to ‘see’ and measure chemical and structural records of time for the first time in natural crystals. My team of HQP will also use new ZAPLab tools to analyse shocked microcrystals in giant impacts in Africa and Canada to establish the variation in behaviour of U-Pb dating minerals during a cratering event so that we can more confidently interpret what we are finding in meteoritic fragments of other bodies in the solar system. With this program my team will tackle fundamental problems such as knowing precisely when water was flowing on ancient Mars. At the same time ZAPLab research will focus on solving economic geology problems such as the age and evolution of ore minerals and ore deposits in Arctic Canada, the Sudbury impact structure and elsewhere where applied scientific training and knowledge transfer is beneficial to industry and to improving ZAPLab research capacity. My expertise in measuring the orientation and chemical microstructure of crystals is also useful in helping others test the strength and corrosion-resistance of manufactured materials, and during the proposed Discovery Grant period I will continue to partner with and train chemists and engineers in a range of projects such as the improvement of metal alloys being considered for ensuring long-term isolation of radioactive waste from the environment. My group has an excellent track record of communicating the results of our research to the public and transferring knowledge to Canadian industry, and all findings from the above research will be communicated at every opportunity as with recent CBC online articles on my Martian research and site visits with Canadian mineral exploration groups. In this way my proposed research program will deliver exciting additional discoveries regarding the age and/or nature of materials to the benefit of Canadian science and industry.

从自然物质中恢复时间信息对于了解行星的历史和勘探其矿产资源至关重要，而锆石等矿物的微晶体是一个令人惊叹的工具。它们是最终幸存的晶体，含有微量的铀，可以用来确定整个太阳系历史上的火山、构造、成矿和撞击事件的年代。在我目前的发现基金任职期间，我建立了一个全国独特的电子纳米束实验室（“ZAPLab”），并建立了一种使用最先进的电子显微镜进行地质年代学的新方法。这使我们能够在以前未被发现的地方找到这些微晶体，并测量它们的生长历史，以及起源和大陨石撞击等事件干扰的特征。我的团队将这种“结构时间”信息与铀的放射性同位素和铅原子的稳定子原子的比例所保存的时间的化学记录结合起来。到目前为止，我的计划已经取得了突破性的成果，最近在我们发表在《自然》杂志上的文章中，我们解决了一个长达数十年的地质年代学难题，揭示了最常见的火星陨石最初形成于年轻的火星超级火山的侧面，而不是40亿年前的地壳（Moser et al. 2013）。由于我们与陨石档案保管员和收集者合作发现了从月球到小行星带的太阳系内陨石中的大量其他定年矿物，预计会有更多的发现。在接下来的五年里，我的团队还将使用原子探测器（Atom Probe）建立一种新的地质年代学方法。原子探测器是一种最新开发的材料科学仪器，可以让我们对晶体中的原子进行三维成像。我们将改进我们早期的结果，表明有可能“看到”和测量自然晶体中时间的化学和结构记录。我的HQP团队还将使用新的ZAPLab工具来分析非洲和加拿大巨大撞击中的震动微晶体，以确定在陨石坑事件中U-Pb定年矿物的行为变化，这样我们就可以更自信地解释我们在太阳系其他天体的陨石碎片中发现的东西。有了这个项目，我的团队将解决一些基本问题，比如精确地知道水在古代火星上是什么时候流动的。同时，ZAPLab的研究将侧重于解决经济地质问题，如加拿大北极地区矿石和矿床的年龄和演化，萨德伯里冲击构造和其他地方的应用科学培训和知识转移有利于工业和提高ZAPLab的研究能力。我在测量晶体取向和化学微观结构方面的专业知识也有助于帮助其他人测试制造材料的强度和耐腐蚀性，在拟议的发现资助期间，我将继续与化学家和工程师合作并培训一系列项目，例如改进正在考虑的金属合金，以确保放射性废物与环境的长期隔离。我的团队在向公众传达我们的研究结果和向加拿大工业转移知识方面有着出色的记录，上述研究的所有发现都将利用每一个机会进行交流，例如最近CBC在线文章中关于我的火星研究和与加拿大矿产勘探小组的实地访问。通过这种方式，我提出的研究计划将为加拿大的科学和工业带来关于材料年龄和/或性质的令人兴奋的额外发现。