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Determinación de parámetros de la red de precisión de las granadas tetragonales (Mg,Fe) SiO3
Science (New York, N.Y.)
|February 9, 1990
Resumen
Los investigadores sintetizaron granates tetragonales, un mineral clave del manto terrestre, bajo alta presión. Se determinaron los parámetros de la red, proporcionando ecuaciones para predecir su tamaño basado en el contenido de hierro.
Área de la Ciencia:
- Física de los minerales Física de los minerales
- La geoquímica es la geoquímica.
- La cristalografía es una técnica de cristalografía.
Sus antecedentes:
- El granate tetragonal (Mg,Fe) SiO(3) es una fase de piroxeno a alta presión.
- Es un componente significativo del manto superior de la Tierra.
- Su estructura cristalina es una versión distorsionada del granate cúbico, lo que lleva a la división de líneas menores en patrones de difracción de rayos X.
Objetivo del estudio:
- Para sintetizar y caracterizar granates tetragonales con diferentes composiciones.
- Para determinar la relación entre la composición y los parámetros de la red.
- Proporcionar ecuaciones predictivas para los parámetros de la red en el sistema MgSiO(3) -FeSiO(3).
Principales métodos:
- Síntesis de granadas tetragonales a aproximadamente 20 gigapascales y 2000 grados C.
- Análisis de los datos de difracción del polvo de rayos X utilizando la descomposición del patrón de polvo entero.
- Determinación de parámetros de celosía (a y c) para muestras apagadas.
Principales resultados:
- Con éxito sintetizó una serie de granates tetragonales en la porción rica en MgSiO ((3)) del sistema MgSiO ((3) -FeSiO ((3).
- Relaciones lineales establecidas entre la fracción molar de FeSiO (x) y los parámetros de la red.
- Ecuaciones derivadas: a = 11.516 + 0.088x y c = 11.428 + 0.157x para 0.0 ≤ x ≤ 0.2.
Conclusiones:
- El estudio proporciona ecuaciones precisas para predecir los parámetros de la red de granate tetragonal basados en el contenido de FeSiO ((3).
- Estos hallazgos mejoran la comprensión del comportamiento mineral de alta presión en el manto de la Tierra.
- Los métodos utilizados son eficaces para el análisis de estructuras cristalinas complejas y la superposición de picos de difracción.
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