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Tamaño de grano - alteración dependiente y la magnetización del basalto oceánico
Science (New York, N.Y.)
|September 9, 1994
Resumen
Los basaltos oceánicos exhiben una magnetización remanente natural que excede sus puntos de Curie debido a múltiples fases magnéticas. Esto indica una rápida alteración de la magnetización en los basaltos del fondo marino.
Área de la Ciencia:
- La geofísica es la geofísica.
- Geología marina Geología marina.
- Magnetismo de las rocas Magnetismo de las rocas.
Sus antecedentes:
- Los basaltos oceánicos registran el campo magnético de la Tierra, crucial para los estudios paleomagnéticos.
- Comprender las propiedades magnéticas de los basaltos es clave para interpretar las anomalías magnéticas marinas.
Objetivo del estudio:
- Investigar las temperaturas de desbloqueo de la magnetización remanente natural en el este del Pacífico Rise basalts.
- Determinar la mineralogía magnética responsable de la magnetización remanente en la corteza oceánica.
Principales métodos:
- Análisis termomagnético para determinar las temperaturas de desbloqueo.
- Análisis microscópico y de propiedades magnéticas de muestras de basalto.
Principales resultados:
- Las temperaturas de desbloqueo superaron los puntos de Curie, lo que indica un comportamiento magnético complejo.
- Se identificaron tres fases magnéticas: titanomagnetita oxidada (residuo dominante), titanomagnetita más gruesa (propiedades de alto campo) y magnetita (producto secundario).
- Se observó una rápida alteración de la magnetización inicial en condiciones del fondo marino.
Conclusiones:
- La presencia de múltiples fases magnéticas explica las altas temperaturas de desbloqueo.
- Los parámetros magnéticos de la roca a granel son insensibles a la alteración, lo que complica las interpretaciones paleomagnéticas.
- La alteración del fondo marino tiene un impacto significativo en la firma magnética de los basaltos oceánicos.
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