Related Experiment Video
Updated: Mar 30, 2026

Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 15, 2013
Evidence for primordial water in Earth's deep mantle
Lydia J Hallis1, Gary R Huss2, Kazuhide Nagashima3
1NASA 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.
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 However, the most accessible reservoir, Earth's oceans, may no longer represent the original (primordial) D/H ratio, owing to changes caused by water cycling between the surface and the interior.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.
Related Concept Videos
States of Water
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
Conditions on Early Earth
Conditions on Early Earth
Deep Sea Microbial Ecology
Origin of Cellular Life
The Water Cycle

