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Propagación hacia el sur de la subducción de Nazca a lo largo de los Andes
Yi-Wei Chen1, Jonny Wu2, John Suppe2
1Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA. yiweichen.tw@gmail.com.
Nature
|January 25, 2019
Resumen
La subducción andina, durante mucho tiempo considerada continua, en realidad involucró fases divergentes episódicas. Este estudio reconstruye la tectónica de placas de Nazca, revelando las interacciones entre la losa de Nazca y el manto inferior influenciado por la compresión y sedimentación andina.
Área de la Ciencia:
- Ciencias de la Tierra
- Geología
- Tectónica de placas
Sus antecedentes:
- El margen andino es un ejemplo clave de subducción de larga duración.
- Su historia geológica desde finales del Mesozoico se ha caracterizado por la deformación episódica y el magmatismo.
- Las explicaciones anteriores involucraron la dinámica de las placas, pero el papel de la tectónica de placas, especialmente la extensa subducción de las placas de Nazca-Farallon, no quedó claro.
Objetivo del estudio:
- Para reconstruir la geometría de las placas tectónicas de la losa de Nazca subducida desde finales del Mesozoico.
- Para desafiar el paradigma de la subducción continua de Nazca.
- Para investigar el vínculo entre el comportamiento de la losa de Nazca y los eventos geológicos andinos.
Principales métodos:
- Utilizamos datos tomográficos para modelar la losa de Nazca.
- Tectónica de placas andinas reconstruida desde el final de la era Mesozoica en adelante.
Principales resultados:
- La fase actual de la subducción de Nazca comenzó a finales del Cretácico (aprox. Hace 80 millones de años) en el norte de los Andes y se propagó hacia el sur.
- La subducción de Nazca alcanzó los Andes del sur por el Cenozoico temprano (aprox. Hace 55 millones de años).
- Contrariamente al paradigma de subducción continua, la subducción de Nazca incluía fases divergentes episódicas.
Conclusiones:
- Las placas tectónicas andinas desde finales del Mesozoico no estaban en un estado estable.
- La subducción de Nazca ha sido episódica, no continua, desde el Mesozoico.
- La sedimentación en profundidad y el inicio de la compresión andina están vinculados a las interacciones entre la losa de Nazca y el manto inferior.
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