Analysis of nano-quantities of geo-materials by Total-Reflectance X-Ray Fluorescence

通过全反射 X 射线荧光分析地质材料的纳米量

• 批准号: RTI-2017-00292
• 负责人: vanHinsberg, Vincent
• 金额: $ 10.93万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 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=616624
• 关键词: Analysis; nano; quantities; geo; materials

Geoscience research takes place at progressively smaller scales, either out of necessity, for example in the simulation of high-pressure high-temperature domains in the Earth where pressure inversely scales with experiment sample size, or by design, for example to interrogate the geological record at increasingly finer time-resolution. This trend produces significant analytical challenges related to the need to quantify the complete periodic table in ever smaller sample quantities. The Total Reflectance X-Ray Fluorescence Spectrometer (TXRF) requested here is ideally suited to overcome these issues. TXRF uses a grazing angle (0.1°) primary X-Ray beam to generate secondary fluorescence X-rays in a thin film of evaporated fluid, suspended solid or rock wafer. The thin-film grazing-angle configuration eliminates element interferences and matrix effects, and allows the detector to be mounted very close to the sample to optimize count rates. As a result, TXRF is characterized by very low backgrounds and can detect elements down to ppb-levels. Moreover, it is non-destructive, can analyse most of the periodic table, and can handle concentrations ranging from mass % to ppb simultaneously. The TXRF instrument will enable a wide diversity of research projects conducted by the co-applicants, including their Discovery Grant research programs. It will allow for the small quantities of fluids and solids synthesized in experiments to be analysed for major and trace elements. This experimental research aims to develop tools to reconstruct the compositions of fluids from the minerals that precipitated from them, and constrain the stability of metals in aqueous fluids to allow for thermodynamic modelling of ore-fluid evolution. The ability to analyse complex fluids and brines without any dilution or other sample pre-processing will be used in studies to determine the cycling of elements between marine sediments and seawater, and to determine whether the sediment acts as a net sink or source of these elements. It will also be applied to understand the environmental impact of acidic metal-laden brines released by Kawah Ijen volcano in Indonesia and to explore the mobility of metals in geothermal fluids in Iceland. Studies of zoned crystals and bedded meta-sediments benefit from the improved sampling resolution enabled by TXRF, which allows for the evolution of magmatic systems and sedimentary basins, respectively, to be investigated at much finer temporal scales. This research greatly enhances our understanding of element cycles and human's impact on these, it allows for past environments to be reconstructed and used as a proxy in forward modelling of climate change, and will provide insights into ore formation, all of which address key societal uncertainties for the future related to pollution, climate change and dwindling natural resources.

地球科学研究的规模逐渐缩小，要么是出于必要，例如模拟地球的高压高温区域，其中压力与实验样本大小成反比，要么是有意为之，例如询问地质记录这种趋势带来了巨大的分析挑战，需要以越来越小的样品量来量化完整的元素周期表，这里要求的全反射 X 射线荧光光谱仪 (TXRF) 是理想的选择。 TXRF 使用掠射角 (0.1°) 初级 X 射线束在蒸发流体、悬浮固体或岩石晶片的薄膜中产生次级荧光 X 射线。 TXRF 的特点是背景非常低，可以检测低至 ppb 级的元素。它是非破坏性的，可以分析大部分元素周期表，并且可以同时处理从质量%到ppb范围的浓度。 TXRF 仪器将使共同申请人能够开展各种研究项目，包括他们的发现资助研究项目，它将允许对实验中合成的少量液体和固体进行主要和痕量元素的分析。研究旨在开发工具来重建从矿物中沉淀出来的流体成分，并限制水性流体中金属的稳定性，以实现矿石流体演化的热力学建模的能力。无需任何稀释或其他样品预处理即可分析复杂的流体和盐水，将用于研究确定海洋沉积物和海水之间的元素循环，并确定沉积物是否充当这些元素的净汇或来源。用于了解印度尼西亚卡瓦伊真火山释放的富含金属的酸性盐水对环境的影响，并探索冰岛地热流体中金属的流动性研究分区晶体和层状。变质沉积物受益于 TXRF 提高的采样分辨率，从而可以在更精细的时间尺度上分别研究岩浆系统和沉积盆地的演化，这项研究极大地增强了我们对元素循环和人类对其影响的理解。 ，它允许重建过去的环境并用作气候变化正向模型的代理，并将提供对矿石形成的见解，所有这些都解决了未来与污染、气候变化和自然减少有关的关键社会不确定性资源。