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Zona de transición de giro en el manto inferior de la Tierra
Jung-Fu Lin1, György Vankó, Steven D Jacobsen
1Lawrence Livermore National Laboratory (LLNL), 7000 East Avenue, Livermore, CA 94550, USA.
Science (New York, N.Y.)
|September 22, 2007
Resumen
El hierro, el hierro, el hierro.
Área de la Ciencia:
- La geofísica es la geofísica.
- Física mineral Física de los minerales
Sus antecedentes:
- Las propiedades minerales en el manto inferior de la Tierra están influenciadas por los estados electrónicos del hierro.
- Estudios anteriores aún no han probado presiones y temperaturas representativas.
- La ferropericlase es un mineral clave en el manto inferior.
Objetivo del estudio:
- Para medir los estados de espín del hierro en ferropericlase del manto inferior bajo alta presión y temperatura.
- Para entender las implicaciones sísmicas de las transiciones de espín de hierro en el manto inferior.
Principales métodos:
- Se utilizó la espectroscopia de emisión de rayos X para medir los estados de espín del hierro.
- Los experimentos se llevaron a cabo en una célula de yunque de diamante calentada con láser.
- Se lograron presiones de hasta 95 gigapascales y temperaturas de hasta 2000 kelvin.
Principales resultados:
- Se observó una transición gradual de espín del hierro en la ferropericlase.
- Esta transición ocurre en un rango de presión-temperatura correspondiente al manto medio-inferior.
- La ferropericlase de baja espina es más densa y tiene velocidades de sonido más rápidas que la ferropericlase de alta espina.
Conclusiones:
- El aumento observado en la ferropericlasa de bajo espín en las condiciones del manto inferior medio creará una zona de transición de espín.
- Esta zona se caracterizará por un gradiente de densidad más pronunciado de lo normal.
- Este hallazgo tiene implicaciones significativas para la interpretación de los datos sísmicos del interior profundo de la Tierra.
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