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Sistemática del cobre en magmas de arco y sus implicaciones para la diferenciación entre la corteza y el manto
Cin-Ty A Lee1, Peter Luffi, Emily J Chin
1Department of Earth Science, Rice University, MS-126, 6100 Main Street, Houston, TX 77005, USA. ctlee@rice.edu
Science (New York, N.Y.)
|April 12, 2012
Resumen
La formación de la corteza continental está relacionada con las condiciones de oxidación. Sin embargo, el seguimiento del cobre revela que los magmas de arco se reducen inicialmente, con la segregación de sulfuro durante la diferenciación que explica el agotamiento de cobre en la corteza.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Petrología Petrología.
- Las configuraciones tectónicas.
Sus antecedentes:
- Los magmas de arco son componentes clave de la corteza continental.
- La formación de continentes a menudo está relacionada con condiciones de oxidación debido a lavas de arco oxidado.
- El estado redox de los magmas de arco es crucial para comprender la evolución de la corteza.
Objetivo del estudio:
- Para investigar el estado redox de los magmas de arco a lo largo de su evolución.
- Para utilizar el cobre (Cu) como indicador redox debido a su afinidad con el azufre.
- Determinar el papel de la diferenciación magmática en la formación de la corteza continental.
Principales métodos:
- Rastrear el contenido de cobre (Cu) en magmas de arco desde la fuente del manto hasta el emplazamiento de la corteza.
- Comparando el contenido de Cu de los basaltos de arco con los basaltos de cordillera de medio océano.
- Analizando el agotamiento de Cu durante la diferenciación magmática debido a la segregación de sulfuro.
Principales resultados:
- Los basaltos de arco primitivo y de cordillera medio oceánica muestran idénticos contenidos de Cu, lo que sugiere estados redox similares.
- La mayoría de las magmas de arco experimentan una disminución significativa del contenido de Cu durante la diferenciación a través de la segregación de sulfuros.
- La corteza continental global exhibe un patrón de agotamiento de Cu similar.
Conclusiones:
- Los magmas de arco primitivo no están necesariamente oxidados.
- La segregación de sulfuros en condiciones de reducción durante la diferenciación magmática es un proceso crítico.
- Este proceso puede ser esencial para la formación de la corteza continental y su característico agotamiento del cobre.
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