Earth Science Frontiers ›› 2020, Vol. 27 ›› Issue (3): 104-122.DOI: 10.13745/j.esf.sf.2020.4.5

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Stable potassium isotope geochemistry and cosmochemistry

WANG Kun1(), LI Weiqiang2,*(), LI Shilei2   

  1. 1. Department of Earth and Planetary Sciences, Washington University in St. Louis, MO 63130, USA
    2. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
  • Received:2020-01-20 Revised:2020-03-21 Online:2020-05-20 Published:2020-05-20
  • Contact: LI Weiqiang

Abstract:

The high-precision potassium (K) stable isotope system is one of the emerging non-traditional isotope systems enabled in recent years by the advance of Multi-Collector Inductively-Coupled-Plasma Mass-Spectrometry (MC-ICP-MS). Here we provide a brief overview on 1) the geochemical and cosmochemical properties of potassium and its major reservoirs, and the abundances of K on earth and in the rest of the Solar System; 2) the history of K isotope studies from 1922 to 2019; 3) the analytical methods of studying K isotopes including column chromatography and mass spectrometry (Thermal Ionization Mass Spectrometry-TIMS, Secondary Ion Mass Spectrometry-SIMS, and MC-ICP-MS); 4) the applications of K stable isotopes in low-temperature geochemistry and biogeochemistry, such as understanding processes of continental weathering, hydrothermal alteration, and reverse weathering; 5) the applications of K stable isotopes in high-temperature geochemistry, such as studying subduction dehydration/metamorphism, tracing subducted oceanic crustal materials and evaluating mantle heterogeneity; and 6) the applications of K stable isotopes on cosmochemistry, such as understanding solar nebular condensation, parent-body processing, planetary formation and magma ocean evolution.

Key words: potassium stable isotopes, isotopic fractionation, continental weathering, hydrothermal alteration, subduction slab tracer, global K cycle, planetary formation

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