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| Titel |
The structure and CO2 solubility of Kimberlite melts |
| VerfasserIn |
Yves Moussallam, Yann Morizet, Pierre Florian, Mickael Laumonier, Malcom Massuyeau, 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 |
250087706
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| Publikation (Nr.) |
 EGU/EGU2014-1766.pdf |
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| Zusammenfassung |
| Kimberlitic magmas have the deepest origin of all terrestrial magmas. They are generated by
low degree partial melting of carbonated mantle peridotite and may originally contain up to
30 wt% CO2. The solubility of CO2 in these melts is therefore expected to exert a prime
influence on the melt buoyancy, structure and henceforth eruption dynamics. The study of
Kimberlitic melt has previously been hampered by the apparent impossibility to quench them
into stable glass. We have studied the CO2 solubility and molecular structure of
successfully quenched CO2-bearing kimberlitic glass by FTIR, Raman and NMR
spectroscopy. Our results suggest that the solubility of CO2 decreases steadily with
increasing amount of network forming cations and that pressure has little effect on
the solubility of CO2 for these compositions up until very shallow depth. Raman
and 29Si NMR investigation suggest that the Kimberlite melt structure is more
polymerised (dominated by Q1 configuration) than theoretically predicted while
13C NMR spectrum show a single resonance peak at -168 ppm similar to that of
non-bridging carbonate species. Understanding the solubility and speciation of CO2 in
Kimberlitic melt has strong implications regarding the carbon content of the cratonic
mantle and carbon’s pathway to the surface in these tectonically lethargic settings. |
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