Development and applications of high precision U-Pb geochronology for earth and planetary sciences

地球与行星科学高精度U-Pb地质年代学的开发与应用

• 批准号: 197303-2011
• 负责人: Davis, Donald
• 金额: $ 2.99万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=546200
• 关键词: Development; applications; precision; Pb; geochronology

The focus of this research is the application of high precision uranium-lead (U-Pb) geochronology to better understand Earth history and the early development of the solar system. The U-Pb system is the most powerful geochronometer partly because determination of precise ages in Precambrian minerals requires only knowledge of the daughter Pb isotopes. Zircon is the most useful mineral for dating terrestrial rocks but its potential for producing ages of the highest possible precision has not yet been fully realized. This proposal is to develop efficient methods for extraction of Pb from zircon and accurate isotopic analysis so as to produce 207Pb-206Pb ages on Precambrian rocks that are an order of magnitude more precise than possible by conventional methods (+/-0.1 Ma instead of +/-1 Ma). This will involve new variations on methods of Pb evaporation and the use of the Neptune Plus, a new multi-collector plasma mass spectrometer with unprecedented sensitivity. The new techniques along with conventional methods will also be applied to dating meteorites and their components, such a silicate chondrules and calcium-aluminum-rich inclusions, to understand early processes of planet formation.

这项研究的重点是应用高精度铀铅（U-Pb）地质年代学，以更好地了解地球历史和太阳系的早期发展。U-Pb系统是最强大的地质年代计，部分原因是确定前寒武纪矿物的精确年龄只需要知道子体Pb同位素。锆石是测定地球岩石年龄的最有用的矿物，但它产生尽可能高精度年龄的潜力尚未完全实现。本研究的目的是发展从锆石中提取Pb的有效方法和精确的同位素分析，从而获得比常规方法精确一个数量级（+/-0.1Ma而不是+/-1Ma）的前寒武纪岩石207 Pb-206 Pb年龄。这将涉及铅蒸发方法的新变化和Neptune Plus的使用，Neptune Plus是一种具有前所未有的灵敏度的新型多收集器等离子体质谱仪。新技术沿着传统方法也将用于测定陨石及其成分的年代，如硅酸盐球粒和富含钙铝的包裹体，以了解行星形成的早期过程。