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Conocimiento del magmatismo de colisión a partir de las huellas isotópicas de las reacciones de fusión
Kurt M Knesel1, Jon P Davidson
1Department of Earth Sciences, University of Queensland, Brisbane, Qld 4072, Australia. k.knesel@earth.uq.edu.au
Science (New York, N.Y.)
|June 22, 2002
Resumen
Se pueden formar fundidos isotópicamente distintos a partir de una sola fuente, con isótopos de estroncio (Sr) que revelan reacciones de fusión. Esto explica las variaciones geoquímicas en las leucogranitas del Himalaya.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Petrología Petrología.
- Geología de Isótopos Geología de Isótopos.
Sus antecedentes:
- La anatéxis, o formación de magma a partir de la fusión de rocas, es crucial para la evolución de la corteza.
- Comprender los procesos que controlan la geoquímica del magma es clave para interpretar las configuraciones tectónicas.
Objetivo del estudio:
- Para investigar cómo una sola fuente puede producir isotópicamente diversos fundidos.
- Para establecer un vínculo entre la composición isotópica del fundido y las reacciones de fusión.
- Para explicar la geoquímica bimodal de las leucogranitas del Himalaya.
Principales métodos:
- Experimentos con cilindros de pistón en sistemas de granito.
- Análisis de las composiciones isotópicas del estroncio (Sr).
- Análisis estequiométrico de las reacciones de fusión.
Principales resultados:
- El derretimiento progresivo de una sola fuente generó fundidos isotópicamente distintos.
- Se encontró una correlación entre la composición isotópica de Sr y la estequiometría de la reacción de fusión.
- Se infirieron distintos episodios de fusión (deshidratación y flujo de fluidos) para las leucogranitas del Himalaya.
Conclusiones:
- Las firmas isotópicas de los magmas anatecticos pueden inferir efectivamente las reacciones de fusión en los sistemas naturales.
- La bimodalidad geoquímica de las leucogranitas del Himalaya probablemente sea el resultado de variadas historias de fusión de una sola fuente metapeletica.
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