Collaborative Research: The Zirconium Isotope Composition and Variability of the Silicate Earth -- A Pilot Study

合作研究：硅酸盐地球的锆同位素组成和变化——一项试点研究

基本信息

批准号：
2131632
负责人：
Mauricio Ibanez-Mejia
金额：
$ 30.95万
依托单位：
University of Arizona
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-05-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2131632&HistoricalAwards=false
关键词：
Collaborative Research Zirconium Isotope Composition

项目摘要

Over the past 60 years the element zirconium (Zr) has been increasingly used as a tool for deciphering the differentiation history of the Earth and other 'rocky' planetary bodies in our Solar System. Despite being a 'trace element' (i.e., element of relatively low concentration) in most geological environments, its preferential enrichment in the chemically differentiated portions of the terrestrial planets - like Earth's continental crust - plays a key role in the presence of accessory minerals like zircon (ZrSiO4) and baddeleyite (ZrO2). In addition to being a cornerstone in the study of geologic time using the Uranium-Lead geochronometer, these accessory minerals are the main carriers of zirconium in the crust and are thus likely to preserve a unique yet unexplored record of the evolution of Zr isotope composition through geologic time. As such, understanding the processes that lead to variability in the isotopic composition of zirconium and how this is recorded in Zr-rich accessory minerals, may provide a window to explore the geochemical evolution of our planet in the deep geologic past, even beyond the oldest preserved rock record currently known in our planet.Shifts in the bonding/coordination environment of tetravalent Zr ions in silicate magmas during zircon and baddeleyite crystallization are expected to result in fractionation (i.e., differential equilibrium incorporation) of its isotopes in precipitated solids and residual melts. This implies that small variations in the abundance of zirconium stable isotopes in terrestrial rocks and minerals have the potential to elucidate how this element behaves and fractionates in high-temperature geological environments. This award will support two early-career investigators to develop techniques to measure zirconium isotopic compositions at high precision and explore, for the first time, the stable zirconium isotopic composition of silicate Earth. The principal goals of this research are threefold: 1) To develop the laboratory materials (e.g., isotopic reference standard and isotopic tracers) necessary for making zirconium isotopic measurements at high-precision. This will be accomplished in collaboration with scientist from the National Institute of Standards and Technology (NIST), who in the future will continue to distribute the standard materials produced during this research; 2) To explore the range of variability in zirconium isotopic abundances of key reservoirs that comprise the solid Earth; 3) Using the newly gained knowledge, explore how variations in the isotopic composition of Zr may be linked to the development, evolution and chemical refinement of the Earth's crust.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.

在过去的60年中，元素锆（ZR）越来越多地用作破译我们太阳系中地球和其他“岩石”行星体的分化历史的工具。尽管在大多数地质环境中是“痕量元素”（即相对浓度相对较低的元素），但在陆地行星的化学区分部分（如地球大陆壳）中，它的优先富集在存在等辅助矿物（如氧化锆（Zrsio4）和Baddeleyite（Zro2）的情况下，它还是起着关键的作用。除了使用铀潜在地球学计的地质时间研究中，这些辅助矿物是地壳中锆的主要载体，因此可能会通过地质时间保留ZR同位素组成的ZR同位素进化记录。 As such, understanding the processes that lead to variability in the isotopic composition of zirconium and how this is recorded in Zr-rich accessory minerals, may provide a window to explore the geochemical evolution of our planet in the deep geologic past, even beyond the oldest preserved rock record currently known in our planet.Shifts in the bonding/coordination environment of tetravalent Zr ions in silicate magmas during zircon and预计Baddeleyite结晶会导致其在沉淀固体和残留熔体中的同位素的分馏（即，差异平衡掺入）。这意味着陆地岩石和矿物质中锆稳定的同位素的丰度很小，有可能阐明该元素在高温地质环境中的行为和分数。该奖项将支持两名早期研究人员开发技术，以高精度测量同位素组合物，并首次探索硅酸盐地球的稳定锆同位素组成。这项研究的主要目标是三重：1）开发实验室材料（例如同位素参考标准和同位素示踪剂），以便在高精度时进行锆同位素测量。这将与国家标准技术研究所（NIST）的科学家合作完成，未来将继续分发这项研究期间生产的标准材料； 2）探索构成固体土的关键储层的锆同位素丰度的变异范围； 3）使用新获得的知识，探索ZR同位素组成的变化如何与地球地壳的开发，进化和化学改进有关。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评估来通过评估来支持的。