Highest terrestial ³He/â´He credibly from the core
The observation that many lavas associated with mantle plumes have higher ³He/â´He ratios than the upper convecting mantle underpins geophysical, geodynamic and geochemical models of Earth's deep interior. High ³He/â´He ratios are thought to derive from the solar nebula or from solar-wind-irr...
| Main Authors: | , , , , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Nature Publishing Group
2023
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| Subjects: | |
| Online Access: | https://doi.org/10.1038/s41586-023-06590-8 https://rdcu.be/do0Bu |
| Summary: | The observation that many lavas associated with mantle plumes have higher ³He/â´He ratios than the upper convecting mantle underpins geophysical, geodynamic and geochemical models of Earth's deep interior. High ³He/â´He 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/â´He component has been considered intrinsic to the mantle, having avoided outgassing caused by giant impacts and billions of years of mantle convection1,2,3,4. Here we report the highest magmatic ³He/â´He 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/â´He helium in these lavas might derive from Earth's core5,6,7,8,9. 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. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law. M. Mahy of Parks Canada Nunavut Field Unit assisted with fieldwork planning. V. Hooten performed mineral separation. N. Chatterjee carried out electron microprobe analyses. This research was funded by the National Science Foundation (award number 1911699). The Woods Hole Oceanographic Institution Andrew W. Mellon Foundation Endowed Fund for Innovative Research and a National Geographic Society grant (CP4-144R-18) supported fieldwork activities. F.H.: conceptualization, methodology, investigation, writing—original draft, visualization, supervision, and funding acquisition. P.D.A.: ... |
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