• 中文核心期刊
  • 中国科技核心期刊
  • CSCD来源期刊
  • DOAJ 收录
  • Scopus 收录

原子探针层析技术及其在矿床研究中的应用

Atom Probe Tomography (APT) and Its Application in Ore Deposits

  • 摘要: 原子探针层析技术(APT)是一种能够以亚纳米分辨率提供定量的三维元素和同位素分析的测试分析技术,具有极高的空间分辨率和低的检出限。虽然原子探针主要用于材料科学和半导体领域,但随着近年来在矿床研究中应用的不断增加,正逐渐成为矿床研究的有用手段。与传统的地质分析技术相比,原子探针具有独特的技术优势,可以测量体积<0.0007μm3的矿物的元素组成,能够在纳米尺度上揭示矿物成分的复杂性,为理解地质演化过程提供全新的认识。本文在简述原子探针层析技术的基本原理、样品的选择和处理以及针尖样品制备的基础上,重点从成矿元素赋存状态、纳米尺度包裹体和稳定同位素组成三个方面阐述了原子探针在矿床研究中的代表性应用成果。迄今为止,原子探针在矿床学中的应用主要集中在成矿元素赋存状态的分析上,尤其是与金矿相关的黄铁矿或其他化学组成相对简单的矿物。而在纳米尺度包裹体和稳定同位素组成方面,原子探针应用成果虽不如前者丰富,但也取得了一些重要的全新认识,表现出良好的应用前景。原子探针在矿床学领域迅速发展的同时,也存在一些亟需解决的问题,如复杂质谱峰的标定、三维重建失真等。尽管如此,相信随着技术的不断进步,原子探针将逐渐成为矿床研究的重要工具。

     

    Abstract: Atom Probe Tomography (APT) is a test analysis technique that provides quantitative three-dimensional element and isotope analysis at subnanometer resolution, with extremely high spatial resolution and low detection limits13. Compared with traditional geological analysis techniques, APT has unique technical advantages, which can be used to analyze the elemental composition of minerals <0.0007μm3 in volume14, reveal the complexity of mineral composition at the nanoscale, and provide a new understanding of the geological evolution process.  APT has been in development for over 50 years, and continuous technological advancements have led to its wider application range. At the beginning of APT design, it was only used for conductive materials. From the end of the 20th century to the beginning of the 21st century, the application of laser pulse mode enabled APT to be applied to semiconductors and insulating materials15-19, and the application of Local Electrode TM Atom Probe (LEAP) improved several key parameters such as the data acquisition rate and mass resolution of APT by several orders of magnitude20. At present, most of the geological application work of APT is carried out by LEAP in laser-assisted mode13. In recent years, the unique technical advantages of APT have attracted increasing attention in geological research, and their advantages in ore deposit research have become more prominent. Some important research results have been published21-31. However, on the whole, its application in ore deposits and even geology is still in its infancy.  The development history, basic principle, selection method of area of interest and needle tip sample preparation of APT are briefly introduced in this paper. Based on this, representative application achievements of APT in ore deposit research by domestic and foreign scholars in recent years are collected and summarized. In ore deposit research, APT is mainly applied in three aspects: the occurrence states of ore-forming elements, nanoscale inclusions, and stable isotope composition21-31. At present, most research results focus on the analysis of the occurrence status of ore-forming elements, especially pyrite or other minerals with simple chemical composition related to gold deposits. APT has successfully revealed three main occurrence states of ore-forming elements on the atomic scale: uniform distribution, nanoparticle and enrichment at low angle grain boundaries and dislocations21-25. For example, gold can be uniformly distributed in the form of dispersed lattice bound gold in the arsenic-rich overgrowth rim of pyrite21, and can form nanoclusters of different sizes in arsenopyrite22. It can also host in the low angle boundary of pyrite related to deformation24. In terms of nano inclusions and stable isotope composition, the research mainly focuses on pyrite nano fluid inclusions and S isotopes26-31. For example, nano telluride inclusions along pyrite fractures in low-sulfidation type epithermal Au-Ag-Te deposit26 and the method for obtaining quantitative δ34S measurement value from APT datasets of pyrite29. The relevant results are shown in Fig.E.1. So far, the applications of APT in ore deposits research have mainly focused on the occurrence state of ore-forming elements, achieving three-dimensional visualization of atomic scale element distribution that was previously unimaginable, providing a new perspective for people to understand and explain the ore-forming process. In terms of nano inclusions and stable isotope composition, although the applications of APT are not as rich as the former, some important new understandings have been obtained, showing a good application prospect.  While APT is rapidly developing in the field of ore deposits, there are still many problems to be solved in its practical application. For example, the extremely small sample volume, time-consuming selection of specific areas, the background noise carried by the mass spectrometry itself, the correct interpretation of complex spectral peaks, and the accuracy of data three-dimensional reconstruction. However, it is foreseeable that with the continuous progress of technology, APT will become more popular and easier to use, increasing numbers of deposit researchers will pay attention to APT, and more ore deposit samples with complex types, structures and chemical compositions will apply this technology for in-depth research, which may change or even completely subvert our understanding of some basic scientific problems in ore deposits.

     

/

返回文章
返回