Evidence for primordial water in Earth's deep mantle

Lydia J Hallis; Gary R Huss; Kazuhide Nagashima; G Jeffrey Taylor; Sæmundur A Halldórsson; David R Hilton; Michael J Mottl; Karen J Meech

doi:10.1126/science.aac4834

Evidence for primordial water in Earth's deep mantle

Science. 2015 Nov 13;350(6262):795-7. doi: 10.1126/science.aac4834.

Authors

Lydia J Hallis¹, Gary R Huss², Kazuhide Nagashima³, G Jeffrey Taylor², Sæmundur A Halldórsson⁴, David R Hilton⁴, Michael J Mottl⁵, Karen J Meech⁶

Affiliations

¹ NASA Astrobiology Institute, Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Drive, Honolulu, HI 96822-1839, USA. Hawai'i Institute of Geophysics and Planetology, Pacific Ocean Science and Technology (POST) Building, University of Hawai'i, 1680 East-West Road, Honolulu, HI 96822, USA. lydia.hallis@glasgow.ac.uk.
² NASA Astrobiology Institute, Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Drive, Honolulu, HI 96822-1839, USA. Hawai'i Institute of Geophysics and Planetology, Pacific Ocean Science and Technology (POST) Building, University of Hawai'i, 1680 East-West Road, Honolulu, HI 96822, USA.
³ Hawai'i Institute of Geophysics and Planetology, Pacific Ocean Science and Technology (POST) Building, University of Hawai'i, 1680 East-West Road, Honolulu, HI 96822, USA.
⁴ Scripps Institution of Oceanography, University California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0244, USA.
⁵ Department of Oceanography, University of Hawai'i, Marine Sciences Building 304, 1000 Pope Road, Honolulu, HI 96822, USA.
⁶ NASA Astrobiology Institute, Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Drive, Honolulu, HI 96822-1839, USA. Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA.

PMID: 26564850
DOI: 10.1126/science.aac4834

Abstract

The hydrogen-isotope [deuterium/hydrogen (D/H)] ratio of Earth can be used to constrain the origin of its water. However, the most accessible reservoir, Earth's oceans, may no longer represent the original (primordial) D/H ratio, owing to changes caused by water cycling between the surface and the interior. Thus, a reservoir completely isolated from surface processes is required to define Earth's original D/H signature. Here we present data for Baffin Island and Icelandic lavas, which suggest that the deep mantle has a low D/H ratio (δD more negative than -218 per mil). Such strongly negative values indicate the existence of a component within Earth's interior that inherited its D/H ratio directly from the protosolar nebula.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.