Advances in high-precision potassium isotope geochemistry: analytical techniques, reservoir compositions, and multi-disciplinary applications

Abstract

Potassium, a moderately volatile and highly incompatible lithophile and biophilic element, possesses two stable isotopes with a substantial mass difference. This characteristic drives significant mass-dependent fractionation during geological processes and generates distinct potassium isotope ratios in different reservoirs. These unique geochemical and cosmochemical properties establish potassium isotopes as powerful tracers in geochemistry, planetary science, and biomedicine. This review synthesizes these advances and highlights the potential of potassium isotopes to address key questions in Earth and planetary science. Integrating historical and recent methodological advances, it begins with a systematic overview of chemical separation techniques, mass spectrometric methodologies, and principal reservoir compositions. Subsequent sections elaborate on applications in low-temperature, high-temperature, and cosmochemical processes. Nevertheless, potassium isotope research remains a developing field, confronting challenges including incomplete standard materials, matrix effects, and purification difficulties. Future progress will likely stem from integrating multiple isotope systems (e.g., coupled K–Li–B–Mg) and expanding interdisciplinary applications. These approaches promise to advance our understanding of Earth system processes, resource and environmental issues, and planetary habitability.