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Segregación de fusión y partición de deformación: implicaciones para la anisotropía sísmica y el flujo del manto
B K Holtzman1, D L Kohlstedt, M E Zimmerman
1Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455, USA. holtz007@umn.edu
Science (New York, N.Y.)
|August 30, 2003
Resumen
La presencia de derretimiento en el manto superior de la Tierra afecta la anisotropía sísmica. La dirección sísmica rápida, normalmente paralela al flujo, puede orientarse 90 grados desde el corte cuando el derretimiento forma zonas débiles, cambiando la forma en que interpretamos la dinámica del manto.
Área de la Ciencia:
- La geofísica es la geofísica.
- Sismología Sismología Sismología.
- Ciencias de la Tierra Sólida Ciencias de la Tierra Sólida
Sus antecedentes:
- Comprender la dinámica del manto superior se basa en la interpretación de la anisotropía sísmica.
- Se supone que la dirección sísmica rápida es paralela al flujo regional paralelo del manto.
- La orientación del eje a de Olivine es clave para la dirección sísmica rápida.
Objetivo del estudio:
- Para investigar el impacto de la presencia de fusión y la segregación en la anisotropía sísmica.
- Reevaluar la relación entre la dirección sísmica rápida y el flujo del manto en regiones parcialmente fundidas.
Principales métodos:
- El estudio examina teóricamente la influencia de la fusión en el alineamiento del eje a de la olivina.
- Modela las deformaciones tridimensionales con redes de fusión segregadas.
- Se analiza la partición de la deformación entre las zonas débil y fuerte.
Principales resultados:
- La presencia de fusión debilita la alineación de los ejes a-a de la olivina.
- La fusión segregada que forma zonas de corte débil causa la alineación del eje a 90 grados desde la dirección de corte.
- Esto indica la partición de la deformación en el manto parcialmente fundido.
Conclusiones:
- La suposición de la dirección sísmica rápida que indica directamente la dirección del flujo se desafía en áreas parcialmente fundidas.
- Se propone una nueva interpretación de la anisotropía sísmica para las regiones deformadas y parcialmente fundidas de la Tierra.
- Este hallazgo ofrece nuevos conocimientos sobre la dinámica de flujo del manto superior.
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