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La compensación del manto de los complejos de núcleos metamórficos activos en la grieta de Woodlark en Papúa Nueva
Geoffrey A Abers1, Aaron Ferris, Mitchell Craig
1Department of Earth Sciences, Boston University, Boston, Massachusetts 02215, USA. abers@bu.edu
Nature
|August 23, 2002
Resumen
Los complejos de núcleos metamórficos acomodan una extensión significativa de la corteza. Los datos sísmicos revelan que la extensión del manto, no solo el flujo de la corteza, soporta estas estructuras de gran elevación en la grieta Woodlark.
Área de la Ciencia:
- La tectónica es la tectónica.
- La geofísica es la geofísica.
- Geología Geología Geología.
Sus antecedentes:
- Los complejos del núcleo metamórfico se forman durante la extensión de la corteza, exhumando rocas de la corteza media.
- Su gran elevación y equilibrio isostático a pesar de la eliminación de la corteza superior siguen siendo objeto de debate.
- Los modelos existentes a menudo asumen que el flujo inferior de la corteza terrestre o la capa subterránea magmática soporta su elevación.
Objetivo del estudio:
- Para investigar la respuesta de la corteza inferior y el manto debajo de los complejos de núcleos metamórficos.
- Comprender los mecanismos que apoyan la elevación topográfica de estas estructuras crustales extendidas.
Principales métodos:
- Se utilizaron observaciones sísmicas para obtener imágenes de la corteza y la estructura del manto superior.
- Análisis del adelgazamiento de la corteza terrestre y las velocidades sísmicas para inferir las propiedades del manto.
Principales resultados:
- Se observó el adelgazamiento de toda la corteza debajo de regiones de gran extensión superficial.
- Identificó rocas del manto de densidad anómala bajo los complejos del núcleo, indicadas por bajas velocidades sísmicas.
- Se midieron tasas de exhumación activa de 5-10 km Myr(-1).
Conclusiones:
- El desarrollo del complejo del núcleo metamórfico implica una extensión significativa del manto.
- El adelgazamiento de la corteza observado es compensado por procesos del manto, no solo por el flujo de la corteza.
- La acomodación de extensión en estos entornos es un fenómeno acoplado de la corteza y el manto.
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