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Representación isotópica del campo de flujo del manto superior de la Tierra
Christine M Meyzen1, Janne Blichert-Toft, John N Ludden
1Laboratoire des Sciences de la Terre, CNRS UMR 5570, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69364 Lyon cedex 07, France. christine.meyzen@ens-lyon.fr
Nature
|June 29, 2007
Resumen
La Tierra La Tierra La Tierra La Tierra La Tierra
Área de la Ciencia:
- Las geociencias son ciencias geológicas.
- Ciencias de la Tierra Ciencias de la Tierra Ciencias de la Tierra
Sus antecedentes:
- El manto de la Tierra juega un papel crucial en la tectónica de placas.
- Comprender los procesos de convección del manto y el reciclaje de materiales es vital para comprender los fenómenos geológicos.
- Los mecanismos que rigen el flujo de retorno de las placas oceánicas subducidas al manto superior no se comprenden completamente.
Objetivo del estudio:
- Para investigar los modos de relleno del manto superior mediante el análisis de firmas geoquímicas.
- Mapear los dominios geoquímicos y su relación con la convección del manto.
- Para entender la influencia de las quillas continentales en los procesos de reabastecimiento del manto superior.
Principales métodos:
- Análisis de isótopos radiogénicos de larga vida, específicamente isótopos de hafnio, a lo largo de la cordillera suroeste de la India.
- Utilizando datos isotópicos para delinear dominios geoquímicos.
- Correlación de dominios geoquímicos con datos sísmicos y actividad de pluma.
Principales resultados:
- Identificó modos de relleno contrastantes del manto superior en diferentes provincias oceánicas.
- Se observó una aguda transición en la composición isotópica del hafnio a lo largo de la cordillera suroeste de la India, lo que indica dominios de manto distintos.
- Encontraron evidencia de influencia isotópica del manto inferior en la provincia india y contaminación por material del manto superior en la provincia del Atlántico Sur.
- El reabastecimiento del manto superior vinculado a la anomalía debajo de Sudáfrica y la pluma Afar.
- Demostró que el arrastre viscoso de las quillas continentales ralentiza y localiza el surgimiento en los dominios atlántico e indio.
- Se observó un aumento más amplio y más rápido en el dominio del Pacífico sin trabas.
Conclusiones:
- Los dominios geoquímicos, mapeados con isótopos radiogénicos, revelan mecanismos contrastantes de relleno del manto superior.
- Las quilas continentales influyen significativamente en el flujo del manto, lo que lleva a un surgimiento localizado.
- El dominio del Pacífico exhibe un relleno del manto más eficiente y generalizado debido a la ausencia de influencia continental.
- El estudio proporciona información sobre los procesos dinámicos que rigen la convección del manto y la tectónica de placas.
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