Highest terrestrial 3He/4He credibly from the core

F Horton; P D Asimow; K A Farley; J Curtice; M D Kurz; J Blusztajn; J A Biasi; X M Boyes

doi:10.1038/s41586-023-06590-8

Highest terrestrial ³He/⁴He credibly from the core

Nature. 2023 Nov;623(7985):90-94. doi: 10.1038/s41586-023-06590-8. Epub 2023 Oct 18.

Authors

F Horton¹, P D Asimow², K A Farley², J Curtice³, M D Kurz³, J Blusztajn³, J A Biasi^{2

4}, X M Boyes²

Affiliations

¹ Geology and Geophysics Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA. fhorton@whoi.edu.
² Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
³ Geology and Geophysics Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
⁴ Department of Earth Sciences, Dartmouth College, Hanover, NH, USA.

PMID: 37853120
DOI: 10.1038/s41586-023-06590-8

Abstract

The observation that many lavas associated with mantle plumes have higher ³He/⁴He ratios than the upper convecting mantle underpins geophysical, geodynamic and geochemical models of Earth's deep interior. High ³He/⁴He ratios are thought to derive from the solar nebula or from solar-wind-irradiated material that became incorporated into Earth during early planetary accretion. Traditionally, this high-³He/⁴He component has been considered intrinsic to the mantle, having avoided outgassing caused by giant impacts and billions of years of mantle convection^1-4. Here we report the highest magmatic ³He/⁴He ratio(67.2 ± 1.8 times the atmospheric ratio) yet measured in terrestrial igneous rocks, in olivines from Baffin Island lavas. We argue that the extremely high-³He/⁴He helium in these lavas might derive from Earth's core^5-9. The viability of the core hypothesis relaxes the long-standing constraint-based on noble gases in lavas associated with mantle plumes globally-that volatile elements from the solar nebula have survived in the mantle since the early stages of accretion.