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Difusión de oxígeno en la perovskita: implicaciones para la conductividad eléctrica en el manto inferior
Science (New York, N.Y.)
|April 23, 1993
Resumen
La difusión de oxígeno en los minerales de perovskita, crucial para comprender el manto profundo de la Tierra, se determinó experimentalmente. Esta investigación confirma un vínculo entre la difusión y la porosidad, lo que sugiere que la conductividad iónica domina el manto inferior.
Área de la Ciencia:
- La geofísica es la geofísica.
- Ciencia de los materiales Ciencia de los materiales.
- Física mineral Física de los minerales
Sus antecedentes:
- Los minerales de perovskita son componentes clave del manto de la Tierra.
- Comprender los mecanismos de difusión en las perovskitas es vital para interpretar los datos geofísicos.
- El titanato de calcio (CaTiO3) sirve como un análogo estructural para las perovskitas del manto inferior.
Objetivo del estudio:
- Para determinar experimentalmente la auto-difusión de oxígeno en la perovskita CaTiO3.
- Para validar una relación teórica entre las constantes de difusión y la porosidad de aniones.
- Para calcular las velocidades de difusión de oxígeno y la conductividad eléctrica en (Mg,Fe) SiO3 perovskita para condiciones del manto inferior.
Principales métodos:
- Medición experimental de la auto-difusión de oxígeno en CaTiO3.3.
- Aplicación de un modelo teórico de difusión relacionando las constantes de difusión con la porosidad aniónica.
- Cálculo de las velocidades de difusión y conductividad eléctrica basado en datos experimentales y modelos teóricos.
Principales resultados:
- Confirmó una relación teórica entre las constantes de difusión y la porosidad de aniones.
- Las tasas de difusión de oxígeno en la perovskita (Mg,Fe) SiO3 aumentan significativamente a través del manto inferior.
- La conductividad eléctrica calculada se alinea con los valores inferidos para el manto profundo.
Conclusiones:
- El estudio valida un modelo para predecir la difusión en perovskitas.
- La conductividad iónica se propone como el mecanismo dominante en el manto profundo.
- Los hallazgos proporcionan información sobre las propiedades eléctricas y el transporte químico en el manto inferior.
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