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Colapso sinorogénico: una perspectiva desde la corteza media, el proterozoico grenville orogen
Science (New York, N.Y.)
|November 1, 1991
Resumen
Una falla extensional importante en el orógeno de Grenville se desarrolló con empuje, lo que indica un colapso de la corteza debido a que se excedieron los límites reológicos. Este evento del Proterozoico refleja los procesos orogénicos modernos en el Himalaya.
Área de la Ciencia:
- Geología Geología Geología.
- La tectónica es la tectónica.
- Geología Estructural Geología estructural.
Sus antecedentes:
- El orógeno de Grenville en Ontario, Canadá, proporciona una ventana clave en la actividad tectónica del Proterozoico medio y tardío.
- La comprensión de los procesos orogénicos, incluyendo fallas y metamorfismo, es crucial para reconstruir la historia geológica de la Tierra.
Objetivo del estudio:
- Investigar la evolución estructural, petrológica y geocronológica del orógeno de Grenville.
- Para determinar la relación entre las fallas extensionales, empuje y metamorfismo durante la orogénesis.
- Para comparar los procesos orogénicos del Proterozoico con ejemplos modernos como el Himalaya.
Principales métodos:
- Análisis estructural de las formaciones rocosas.
- Examen petrológico de muestras de rocas.
- La datación geocronológica para establecer líneas de tiempo.
Principales resultados:
- Una falla extensional significativa se inició sincrónicamente con el empuje en etapa tardía en el orógeno de Grenville.
- Esta falla se extendía a profundidades de al menos 25 kilómetros dentro de la corteza.
- El momento y la distribución espacial de las fallas, el metamorfismo y la compresión sugieren un sobreengrosamiento de la corteza terrestre y su posterior colapso.
Conclusiones:
- El colapso sinorogénico fue provocado por la corteza que excede su capacidad de soporte reológico.
- Los cinturones orogénicos proterozoicos como el de Grenville compartían similitudes en la altura fisiográfica, el grosor de la corteza y la fuerza con los sistemas orogénicos modernos como el Himalaya.
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