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El inicio de la subducción: ¿criticalidad por adición de agua?
K Regenauer-Lieb1, D A Yuen, J Branlund
1Institute of Geophysics, Eidgenössische Technische Hochschule-Hönggerberg, Swiss Federal Institute of Technology, 8093 Zürich, Switzerland. klaus@tomo.ig.erdw.ethz.ch
Science (New York, N.Y.)
|October 20, 2001
Resumen
El agua juega un papel clave en el inicio de la subducción, un proceso fundamental en la tectónica de placas. Los modelos numéricos muestran que la inestabilidad termomecánica inducida por el agua, impulsada por la carga sedimentaria, puede desencadenar la subducción litosférica durante millones de años.
Área de la Ciencia:
- La geofísica es la geofísica.
- La tectónica es la tectónica.
- La geodinámica es la geodinámica.
Sus antecedentes:
- La subducción es un proceso crítico en la tectónica de placas, responsable del reciclaje de la litosfera oceánica en el manto.
- Los mecanismos precisos que inician la subducción siguen siendo poco conocidos, lo que dificulta nuestra comprensión de la evolución tectónica de placas.
Objetivo del estudio:
- Para investigar el papel del agua en el inicio de la subducción.
- Para explorar las inestabilidades termomecánicas que impulsan el descenso litosférico en el manto.
Principales métodos:
- Se utilizaron modelos de elementos finitos de alta resolución (resolución < 1 km).
- Incorporó datos reológicos de la litosfera en los modelos.
- Simuló los efectos de la carga sedimentaria y la presencia de agua en el comportamiento litosférico.
Principales resultados:
- Una inestabilidad termomecánica sólido-fluido es necesaria para iniciar la subducción.
- La carga sedimentaria puede desencadenar esta inestabilidad en escalas de tiempo geológicas (aprox. 100 millones de años).
- El agua actúa como un lubricante, promoviendo un doble mecanismo de retroalimentación (termoelástico y térmico-reológico) que impulsa la subducción.
Conclusiones:
- El agua es un factor crucial en el inicio de la subducción.
- El inicio de la subducción puede ser un proceso lento, impulsado por retroalimentaciones térmicas y reológicas combinadas facilitadas por la lubricación con agua.
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