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| Titel |
Electrical Conductivity of H2O-CO2 rich-Melt in the Mantle and the construction of petrology-based conductivity profiles |
| VerfasserIn |
David SIFRE, Leila Hashim, Fabrice Gaillard |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250097627
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| Publikation (Nr.) |
 EGU/EGU2014-13227.pdf |
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| Zusammenfassung |
| Electromagnetic data images mantle regions more conductive than that of dry olivine. There
is no doubt that melt are thermodynamically stable and present in the LAB, but how they can
impact on mantle electrical conductivity remains debated. In particular, petrological studies
realized some 30 years ago have shown that peridotites exposed at the P-T-fO2 conditions of
the LAB produced H2O and CO2 rich-melts. But electrical conductivities of these melts are
poorly known.
So we have been performed electrical conductivity experimentation in piston cylinder on
H2O-CO2 rich melts. We have explored different melt compositions, from carbonated melts
to basalts. We have determined the effect of chemical compositions and volatiles on
these melts. The electrical conductivity measurements have shown that hydrous
carbonated melts are very conductive, and the incorporation of basalt decreases the
conductivity. With these new data, we have produced a semi-empirical law predicting the
conductivity as a function of H2O and CO2 contents. Based on this law and the
electrical conductivity of olivine, we have constructed 1D conductivity profiles.
With these profiles, we discuss the effect of volatiles content (in the melt and in the
mantle), melt fractions (mixing law and interconnection of the melt) and T-P on
conductivity. And finally, we conclude that the electrical conductivities of the mantle is a
powerful to track the fundamental process of mantle incipient melting, which is
in turn narrowly associated to the cycling of H2O and CO2 in the upper mantle. |
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