Chang Su-Chin, Shi Wenbei, Wang Yinzhi, Wang Fei
Department of Earth Sciences, The University of Hong Kong, Hong Kong 999077, China.
Institutional Center for Shared Technologies and Facilities, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
Natl Sci Rev. 2025 Jul 8;12(9):nwaf277. doi: 10.1093/nsr/nwaf277. eCollection 2025 Sep.
Given that K constitutes about 3 wt.% of Earth's crust and is present in most rock-forming minerals, and that Ar diffusion in minerals is temperature-dependent, Ar-based geochronology (Ar/Ar and K-Ar dating) can date most rocks and also reveal their thermal history. This paper reviews recent advances and longstanding limitations in Ar/Ar and K-Ar geochronology, and provides perspectives into future research on Ar-based geochronometers. Over the past two decades, multi-collector noble gas mass spectrometry has witnessed remarkable advancements in both sensitivity and resolution. Successive upgrades of mass spectrometer generations have significantly enhanced the precision of Ar isotope measurements, enabling a comprehensive revision and optimization of Ar/Ar dating standard minerals. To achieve high-precision Ar/Ar dating and minimize inter-laboratory discrepancies, researchers are focusing on refining the potassium decay constant, developing standardized mineral separation techniques, and harmonizing irradiation and data processing protocols. These efforts are pivotal for improving the analytical precision of low-K and young samples, thereby expanding the application frontiers of Ar/Ar geochronology. For planetary dating, the K/Ar method currently remains the only feasible radiometric technique among radioactive isotope systems. Addressing challenges in simultaneous K and Ar measurements will facilitate streamlined acquisition of reliable datasets. Moreover, research is advancing toward a deeper understanding of Ar diffusion behavior in minerals-beyond temperature-dependent volume diffusion-to clarify its impact on Ar/Ar data interpretation and geological significance. To further advance argon-based geochronology, the scientific community is committed to continuous exploration and resolution of methodological limitations inherent in these dating approaches.
鉴于钾占地球地壳的约3%（质量分数），且存在于大多数造岩矿物中，并且矿物中的氩扩散与温度相关，基于氩的地质年代学（氩-氩和钾-氩测年）可以测定大多数岩石的年代，并揭示它们的热历史。本文综述了氩-氩和钾-氩地质年代学的最新进展和长期存在的局限性，并对基于氩的地质年代计的未来研究提供了展望。在过去二十年中，多接收惰性气体质谱仪在灵敏度和分辨率方面都取得了显著进展。质谱仪几代的连续升级显著提高了氩同位素测量的精度，使得对氩-氩测年标准矿物进行全面修订和优化成为可能。为了实现高精度氩-氩测年并最小化实验室间差异，研究人员专注于完善钾衰变常数、开发标准化矿物分离技术以及统一辐照和数据处理协议。这些努力对于提高低钾和年轻样品的分析精度至关重要，从而扩展了氩-氩地质年代学的应用前沿。对于行星测年，钾-氩方法目前仍然是放射性同位素体系中唯一可行的放射性测年技术。解决钾和氩同时测量中的挑战将有助于简化获取可靠数据集的过程。此外，研究正在朝着更深入理解矿物中氩的扩散行为——超越与温度相关的体积扩散——以阐明其对氩-氩数据解释和地质意义影响的方向推进。为了进一步推动基于氩的地质年代学发展，科学界致力于持续探索并解决这些测年方法中固有的方法学局限性。
