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La disolución de piroxenos y anfiboles durante la intemperie
Science (New York, N.Y.)
|March 14, 1980
Resumen
El desgaste de minerales de silicato ocurre a través del grabado selectivo, formando hoyos en forma de lente en los afloramientos de luxación. Este proceso, observado en minerales como la augita y la hornblenda, desafía las teorías tradicionales de difusión a granel.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- La mineralogía es la Mineralogía.
- Ciencias de la Tierra Ciencias de la Tierra Ciencias de la Tierra
Sus antecedentes:
- El desgaste de silicatos es un proceso clave en la formación del suelo y el ciclo elemental.
- Las teorías existentes a menudo proponen un ataque general de superficie y redondeo debido a la difusión masiva.
- Los mecanismos a microescala de la disolución de minerales durante la intemperie requieren una mayor aclaración.
Objetivo del estudio:
- Para investigar los mecanismos a microescala de la disolución de minerales de silicato durante la intemperie.
- Para caracterizar la morfología del pozo de grabado y la formación en minerales de silicato específicos.
- Para comparar las características de grabado inducidas en laboratorio con los fenómenos naturales de la intemperie.
Principales métodos:
- Observación microscópica de las fosas de grabado en minerales de silicato desgastados (augita, hipersteno, diopside, hornblende).
- Experimentos de laboratorio que tratan estos minerales con ácido fluorhídrico concentrado y ácido clorhídrico.
- Análisis de la forma y orientación del pozo de grabado en relación con la cristalografía mineral.
Principales resultados:
- Se forman y se aglutinan hoyos de grabado distintivos, paralelos y en forma de lente en la disolución de augita, hipersteno, diopside y hornblenda.
- Las características de grabado similares se replican en experimentos de laboratorio utilizando tratamiento ácido.
- La formación de hoyos de grabado está vinculada a afloramientos de dislocación, con una forma dictada por la cristalografía mineral.
Conclusiones:
- Es probable que el desgaste de silicato proceda a través del grabado selectivo en sitios específicos, como las dislocaciones.
- La morfología observada del pozo de grabado apoya un mecanismo de disolución selectiva en lugar de un ataque general a la superficie.
- Los hallazgos desafían los modelos de intemperie basados en la difusión a granel y resaltan la importancia del control cristalográfico.
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