Conditions Extrêmes et Matériaux : Haute Température et Irradiation

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F.Gaillard, M.Malki, G.Iacono-Marziano, B.Scaillet, M.Pichavant, 'Carbonatite melts and electrical conductivity in the asthenosphere', Science 322 1363-1365 (2008) doi:10.1126/science.1164446

Electrically conductive regions in the Earth mantle have been interpreted to reflect the presence of either silicate melt or water dissolved in olivine. On the basis of laboratory measurements we show that molten carbonates have electrical conductivities that are 3 orders of magnitude higher than those of molten silicate and 5 orders of magnitude higher than those of hydrated olivine. Many conductive regions of the mantle may thus reflect the presence of small amounts of pervasive molten carbonates that are thermodynamically stable in the upper mantle. The deep conductive oceanic asthenosphere can be explained by a small amount of carbonatite melts (~0.1 vol.%), which is the likely source of CO2 in Mid Ocean Ridge Basalts.