Low helium flux from the mantle inferred from simulations of oceanic helium isotope data

Daniele Bianchi, Jorge L. Sarmiento, Anand Gnanadesikan, Robert M. Key, Peter Schlosser, Robert Newton

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

The high 3He/4He isotopic ratio of oceanic helium relative to the atmosphere has long been recognized as the signature of mantle 3He outgassing from the Earth's interior. The outgassing flux of helium is frequently used to normalize estimates of chemical fluxes of elements from the solid Earth, and provides a strong constraint to models of mantle degassing. Here we use a suite of ocean general circulation models and helium isotope data obtained by the World Ocean Circulation Experiment to constrain the flux of helium from the mantle to the oceans. Our results suggest that the currently accepted flux is overestimated by a factor of 2. We show that a flux of 527±102mol year-1 is required for ocean general circulation models that produce distributions of ocean ventilation tracers such as radiocarbon and chlorofluorocarbons that match observations. This new estimate calls for a reevaluation of the degassing fluxes of elements that are currently tied to the helium fluxes, including noble gases and carbon dioxide.

Original languageEnglish (US)
Pages (from-to)379-386
Number of pages8
JournalEarth and Planetary Science Letters
Volume297
Issue number3-4
DOIs
StatePublished - Sep 1 2010
Externally publishedYes

Keywords

  • Degassing
  • Helium isotopes
  • Mantle geochemistry
  • Ocean tracers

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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