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El hermanamiento en MgSiO3 Perovskita
Science (New York, N.Y.)
|April 27, 1990
Resumen
La perovskita de silicato de magnesio (MgSiO3) sintetizada bajo alta presión muestra simetría ortorrómbica. El análisis microestructural revela dominios gemelos, lo que sugiere que una estructura cúbica puede ser estable bajo ciertas condiciones, incluyendo potencialmente el manto inferior de la Tierra.
Área de la Ciencia:
- Física mineral Física de los minerales
- La geoquímica es la geoquímica.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- La perovskita MgSiO3 es un mineral clave en el manto inferior de la Tierra.
- Comprender sus transformaciones de fase bajo alta presión y temperatura es crucial para los modelos geodinámicos.
- Estudios anteriores indicaron simetría ortorrómbica bajo condiciones ambientales.
Objetivo del estudio:
- Para investigar la microestructura de la perovskita MgSiO3 sintetizada bajo condiciones extremas.
- Comprender el papel de los dominios gemelos en las transformaciones de fase.
- Para inferir la fase estable de la perovskita MgSiO3 bajo condiciones experimentales y del manto inferior.
Principales métodos:
- Síntesis a alta presión y alta temperatura de la perovskita MgSiO3.
- Microscopía electrónica de transmisión (TEM) para el análisis microestructural.
- Análisis de las relaciones de dominios gemelos y orientaciones cristalográficas.
Principales resultados:
- Los cristales de perovskita MgSiO3 sintetizados mostraron simetría ortorrómbica en condiciones ambientales.
- TEM reveló una microestructura dominada por dominios gemelos relacionados por {112} y {110} planos de reflexión.
- Es probable que estos gemelos sean artefactos de las transiciones de fase de cúbico a tetragonal y de tetragonal a ortorrómbico al disminuir la presión/temperatura.
Conclusiones:
- Los dominios gemelos observados sugieren que la estructura cúbica de perovskita podría ser la fase estable bajo las condiciones de síntesis experimental.
- Este hallazgo tiene implicaciones para la composición y estructura del manto inferior de la Tierra.
- Se necesitan más investigaciones para confirmar el campo de estabilidad de las fases de perovskita MgSiO3.
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