Evidence for primordial water in Earth’s deep mantle

• Autores: Lydia J. Hallis, Gary R. Huss, Kazuhide Nagashima
• Localización: Science, ISSN 0036-8075, Vol. 350, Nº 6262, 2015, págs. 796-797
• Idioma: inglés
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• Resumen

  • 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 However, the most accessible reservoir, Earth’s oceans, may no longer represent the original (primordial) D/H ratio, owing to changes caused by water cycling between the surface and the interior.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.