El origen de los terranos granulares y la formación de la corteza continental más baja
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Science (New York, N.Y.)
|April 21, 1989
Resumen
Los terranos granulados representan los niveles medios de la corteza, no la corteza más baja como se creía anteriormente. Este hallazgo, basado en datos de presión de granulitas y xenolitos, revisa nuestra comprensión de la estructura de la corteza terrestre.
Área de la Ciencia:
- Geología Geología Geología.
- Petrología Petrología.
- La tectónica es la tectónica.
Sus antecedentes:
- Los terranos granulados son clave para comprender la evolución de la corteza terrestre.
- Las suposiciones anteriores sugerían que los terranos de granulita se originaron en la corteza más baja.
- Los xenolitos de granulita ofrecen información sobre los procesos más profundos de la corteza.
Objetivo del estudio:
- Para diferenciar los niveles de la corteza representados por terranos de granulita expuestos y xenolitos de granulita.
- Para refinar la comprensión de las presiones de la corteza terrestre y las profundidades asociadas con la formación de granulados.
- Investigar los mecanismos detrás del engrosamiento de la corteza terrestre y la formación de granulados.
Principales métodos:
- Análisis comparativo de las composiciones de granulado terráneo y xenolito.
- Aplicación de barómetros calibrados para determinar las presiones de equilibrio.
- Interpretación geológica de los datos de presión en el contexto de la estructura de la corteza.
Principales resultados:
- Los terrenos de granulita expuestos registran presiones de equilibrio más bajas (0.60.8 GPa, 2030 km de profundidad).
- Los xenolitos de granulita indican presiones significativamente más altas (≥1.01.5 GPa, 3550 km de profundidad).
- Los terranos granulados representan los niveles de la corteza media a media baja, no la corteza más baja.
Conclusiones:
- Los terranos granulados no representan una corteza inferior exhumada.
- El engrosamiento de la corteza terrestre a través de la cristalización del magma máfico en el límite entre la corteza y el manto es un mecanismo plausible.
- Este proceso explica tanto los terranos granulados regionales como los xenolitos de la corteza máfica profundamente asentados.
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