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Tensión de corte alto de los agregados de olivino: consecuencias reológicas y sísmicas
M Bystricky1, K Kunze, L Burlini
1Geologisches Institut, ETH-Zentrum, 8092 Zürich, Switzerland. misha@erdw.ethz.ch
Science (New York, N.Y.)
|November 25, 2000
Resumen
Los experimentos de alta presión revelan el debilitamiento de la tensión en los agregados de olivino, lo que afecta el flujo del manto superior. Esta anisotropía sísmica puede no reflejar la orientación del plano de cizallamiento en rocas recristalizadas.
Área de la Ciencia:
- La geofísica es la geofísica.
- Física mineral Física de los minerales
- La tectónica es la tectónica.
Sus antecedentes:
- El desplazamiento por dislocación en el olivino es un mecanismo clave de deformación en el manto superior de la Tierra.
- Comprender el comportamiento del olivino en condiciones extremas es crucial para el modelado geodinámico.
Objetivo del estudio:
- Para investigar el debilitamiento de la deformación y la recristalización en agregados de olivino bajo alta presión y torsión a alta temperatura.
- Evaluar las implicaciones de estos procesos para el flujo del manto superior y la anisotropía sísmica.
Principales métodos:
- Experimentos de torsión a alta presión y alta temperatura en agregados de olivino.
- Análisis del debilitamiento de la deformación, la recristalización de la rotación del subgrano y la orientación preferida de la celosía.
Principales resultados:
- Se observó un debilitamiento de la deformación del 15-20% antes de la deformación en estado de equilibrio.
- Se identificaron la recristalización de la rotación del subgrano y la orientación preferida de la red fuerte.
- La propagación de las ondas sísmicas en regiones altamente tensas será anisotrópica.
Conclusiones:
- El debilitamiento de la deformación puede facilitar el flujo del manto superior sin alterar los mecanismos de deformación.
- Las leyes de flujo existentes basadas en datos de baja tensión pueden ser inadecuadas para regiones de alta tensión.
- La anisotropía en el olivino recristalizado altamente tensado no indica la orientación del plano de cizallamiento.
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