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Hierro nativo en la corteza inferior continental: implicaciones petrológicas y geofísicas
Science (New York, N.Y.)
|August 16, 1985
Resumen
El hierro nativo (Fe(0) encontrado en los xenolitos de la corteza inferior sugiere un entorno reducido en la corteza profunda de la Tierra. Este descubrimiento impacta las interpretaciones de las anomalías magnéticas originadas en la litosfera.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- La mineralogía es la Mineralogía.
- La geofísica es la geofísica.
Sus antecedentes:
- Los xenolitos de granulita de la corteza inferior proporcionan información sobre los procesos profundos de la Tierra.
- El hierro nativo (Fe(0) rara vez se encuentra en tales entornos geológicos.
Objetivo del estudio:
- Investigar la presencia e implicaciones del hierro nativo en los xenolitos de la corteza inferior.
- Para determinar el estado de oxidación de la corteza inferior continental y el manto superior.
Principales métodos:
- Análisis de xenolitos de una tubería de kimberlita en el oeste de África.
- Mediciones magnéticas para cuantificar la abundancia de metales de hierro.
- Geotermometría y geobarometría de oxígeno para determinar las condiciones de equilibrio.
Principales resultados:
- Hierro nativo (Fe(0)) identificado como un producto de descomposición del granate y la ilmenita.
- El metal de hierro constituye menos del 0,1% en volumen.
- Se produjo un equilibrio entre los tampones de hierro-wüstita y magnetita-wüstita.
Conclusiones:
- Los amortiguadores de hierro-wüstita y magnetita-wüstita observados pueden representar el estado de oxidación de la corteza inferior continental y el manto superior litosférico agotado.
- El hierro ferromagnético nativo es estable hasta aproximadamente 95 km de profundidad.
- Este hallazgo es crucial para interpretar las anomalías magnéticas estáticas de larga longitud de onda.
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