Abundances of Uranium and Thorium Elements in Earth Estimated by Geoneutrino Spectroscopy

(The KamLAND Collaboration)

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The decay of the primordial isotopes 238U, 235U, 232Th, and 40K has contributed to the terrestrial heat budget throughout the Earth's history. Hence, the individual abundance of those isotopes are key parameters in reconstructing contemporary Earth models. The geoneutrinos produced by the radioactive decays of uranium and thorium have been observed with the Kamioka Liquid-Scintillator Antineutrino Detector (KamLAND). Those measurements have been improved with more than 18-year observation time, and improvement in detector background levels mainly with an 8-year nearly reactor-free period, which now permit spectroscopy with geoneutrinos. Our results yield the first constraint on both uranium and thorium heat contributions. The KamLAND result is consistent with geochemical estimations based on elemental abundances of chondritic meteorites and mantle peridotites. The High-Q model is disfavored at 99.76% C.L. and a fully radiogenic model is excluded at 5.2σ assuming a homogeneous heat producing element distribution in the mantle.

Original languageEnglish
Article numbere2022GL099566
JournalGeophysical Research Letters
Issue number16
Publication statusPublished - 2022 Aug 28


  • Earth's interior
  • geoneutrino
  • mantle composition
  • radiogenic heat

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)


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