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La carbonatita se derrite y la conductividad eléctrica en la astenosfera
Fabrice Gaillard1, Mohammed Malki, Giada Iacono-Marziano
1Institut National des Sciences de l'Univers (INSU), Université d'Orléans, Université François Rabelais-Tours, Institut des Sciences de la Terre d'Orléans, UMR 6113, 41071 Orléans cedex 2, France. gaillard@cnrs-orleans.fr
Science (New York, N.Y.)
|November 29, 2008
Resumen
Los carbonatos fundidos, no los silicatos fundidos o el agua, explican la alta conductividad eléctrica en el manto de la Tierra. Este hallazgo sugiere la concentración de carbono en el manto superior, detectable a través de mediciones de conductividad del manto.
Área de la Ciencia:
- La geofísica es la geofísica.
- La geoquímica es la geoquímica.
- Física mineral Física de los minerales
Sus antecedentes:
- Las regiones eléctricamente conductivas en el manto de la Tierra se atribuyen típicamente al derretimiento de silicatos o al agua en olivina.
- Comprender la conductividad del manto es crucial para interpretar su composición y sus procesos.
Objetivo del estudio:
- Para investigar la conductividad eléctrica de carbonatos fundidos.
- Para determinar si los carbonatos fundidos pueden explicar las altas conductividades eléctricas observadas en la astenosfera.
- Para vincular la conductividad del manto a la concentración de carbono.
Principales métodos:
- Mediciones de laboratorio de la conductividad eléctrica para carbonatos fundidos, silicatos fundidos y olivino hidratado.
- Comparación de datos de laboratorio con observaciones geofísicas de la conductividad astenosférica.
Principales resultados:
- Los carbonatos fundidos exhiben conductividades eléctricas tres órdenes de magnitud más altas que los silicatos fundidos.
- Los carbonatos fundidos son cinco órdenes de magnitud más conductores que el olivino hidratado.
- La conductividad astenosférica puede explicarse por aproximadamente el 0,1% de carbonatita derretida en peridotita.
Conclusiones:
- La alta conductividad eléctrica en la astenosfera probablemente indica la presencia de pequeñas cantidades de carbonato fundido.
- La conductividad del manto proporciona una nueva aproximación para estimar la concentración de carbono en el manto superior.
- Los hallazgos se alinean con los niveles de dióxido de carbono observados en los basaltos de la cresta oceánica media.
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