Hydrogen isotopic evidence for a core component in Baffin Island lavas.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40267189.
- Also identified by DOI 10.1126/sciadv.adr2917 and PMC identifier 13109940.
- Licence recorded as CC BY-NC.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
The nature of chemical exchange between Earth's core and mantle is fundamental to understanding their evolution. Tungsten-182 and helium-3 anomalies in volcanic rocks from deeply sourced mantle plumes have been attributed to core-mantle exchange. Hydrogen (H) is potentially abundant in the core. Therefore, H may also be a sensitive tracer of core-mantle exchange. We measured <sup>2</sup>H/<sup>1</sup>H ratios (reported as δD) in olivine-hosted basaltic melt inclusions from a Baffin Island lava to test whether mantle plumes contain H from the core. The average δD value (-144 ± 24 per mil) is lower than some estimates for the average depleted upper mantle (δD ≈ -60 ± 20 per mil). The low δD composition likely derives from isotopic diffusion or H leakage from the core, not isotopic fractionation during magmatism or crustal contamination. Over geologic time, core-mantle exchange of H may have overprinted the isotopic composition of mantle plume source regions and much of the upper mantle.