¹Laurette Piani,¹Yves Marrocchi,¹Thomas Rigaudier,^1,2Lionel G. Vacher,¹Dorian Thomassin,¹Bernard Marty
Science 369, 1110-1113 Link to Article [DOI: 10.1126/science.aba1948
Article]
¹Centre de Recherches Pétrographiques et Géochimiques (CRPG), Centre National de Recherche Scientifique (CNRS)–Université de Lorraine, Vandoeuvre-les-Nancy, F-54500, France.
²Department of Physics, Washington University in St. Louis, St. Louis, MO 63130, USA.
Reprinted with permission from AAAS

The origin of Earth’s water remains unknown. Enstatite chondrite (EC) meteorites have similar isotopic composition to terrestrial rocks and thus may be representative of the material that formed Earth. ECs are presumed to be devoid of water because they formed in the inner Solar System. Earth’s water is therefore generally attributed to the late addition of a small fraction of hydrated materials, such as carbonaceous chondrite meteorites, which originated in the outer Solar System where water was more abundant. We show that EC meteorites contain sufficient hydrogen to have delivered to Earth at least three times the mass of water in its oceans. EC hydrogen and nitrogen isotopic compositions match those of Earth’s mantle, so EC-like asteroids might have contributed these volatile elements to Earth’s crust and mantle.