Skip to Main content Skip to Navigation
Conference papers

Helium and neon isotopes in the mantle: constraints on the origin of volatiles on Earth

Abstract : It is now obvious that the mantle neon is solar-like. The possibility that the origin of this solar flavor is due to incorporation of irradiated parent bodies during accretion (e.g. gas rich meteorites) has been evoked by Trieloff and collaborators. The main argument is the fact there are no precise 20Ne/22Ne measured ratios above 13 in oceanic basalts, whereas the solar wind has a 20Ne/22Ne of 13.8 and the "neon B" neon shows a ratio of 12.6-12.8. The second argument for an irradiated origin is the air-like 38Ar/36Ar in mantle-derived samples (the "neon B" argon is close to air), distinct from the solar argon. Here we present another argument for an irradiated origin of the rare gases in the Earth. The global correlation in oceanic basalts (MORB and OIB) between 4He/3He and 21Ne/22Ne (corrected for air contamination) gives a mixing hyperbolae with a r parameter (r=(3He/22Ne)MORB/(3He/22Ne)PM) close to 10. It is now clear that 3He/22Ne ratio in the MORB source is around 7, giving for the primitive mantle (PM) a 3He/22Ne of 0.7. The solar 3He/22Ne ratio is estimated at 5-6 whereas the gas rich meteorites show a ratio of 0.3. Therefore, the global correlation in oceanic basalts between the helium and neon isotopic ratios suggests that (some) parent bodies of the Earth were gas rich meteorites, irradiated by an energetic solar wind during the planetary accretion.
Document type :
Conference papers
Complete list of metadata

https://hal-insu.archives-ouvertes.fr/insu-03603240
Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Wednesday, March 9, 2022 - 5:07:22 PM
Last modification on : Friday, March 11, 2022 - 3:31:51 AM

Identifiers

Citation

Manuel Moreira. Helium and neon isotopes in the mantle: constraints on the origin of volatiles on Earth. American Geophysical Union, 0000, à renseigner, Unknown Region. ⟨insu-03603240⟩

Share

Metrics

Record views

12