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Enriquecimiento de osmio-187 en algunos penachos: ¿evidencia de interacción núcleo-manto?
Science (New York, N.Y.)
|August 11, 1995
Resumen
El núcleo externo de la Tierra puede tener mayores proporciones de renio/osmio y osmio-187/osmio-188 que el manto superior condrítico. Esta firma isotópica, originada en el límite núcleo-manto, es detectable en las plumas del manto.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- La geofísica es la geofísica.
- Ciencias planetarias Ciencias planetarias.
Sus antecedentes:
- El límite entre el núcleo y el manto de la Tierra (capa D) es una región clave para comprender la diferenciación planetaria.
- Las relaciones isotópicas de elementos como el osmio proporcionan marcadores cruciales para los procesos geológicos.
Objetivo del estudio:
- Para investigar la composición isotópica potencial del núcleo externo de la Tierra.
- Para determinar si el material del núcleo puede ser detectado en plumas del manto.
Principales métodos:
- Utilizando cálculos basados en datos del núcleo de los asteroides.
- Analizando las relaciones renio/osmio y osmio-187/osmio-188.
Principales resultados:
- El núcleo externo de la Tierra puede poseer una proporción de renio/osmio al menos un 20% más alta que el manto superior condrítico.
- La proporción de osmio-187/osmio-188 del núcleo exterior podría ser al menos un 8% mayor que las condritas.
- El enriquecimiento isotópico de osmio en sistemas derivados de plumas (5-20% más alto que las condritas) es consistente con una fuente límite núcleo-manto.
Conclusiones:
- El núcleo externo es probablemente enriquecido en renio y osmio en comparación con el manto condrítico.
- Las plumas del manto pueden llevar la firma isotópica del límite núcleo-manto.
- Esto proporciona evidencia de intercambio de material entre el núcleo y el manto.
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