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Las restricciones a la formación de dolomita sedimentaria
Science (New York, N.Y.)
|July 10, 1981
Resumen
La dolomitización, el reemplazo de la calcita y la aragonita por la dolomita, ocurre en entornos marinos y lacustres con bajo contenido de sulfato y una diagenesis mínima de sílice. La transformación de sílice a cuarzo favorece la formación de dolomita, mientras que la transformación de ópalo-A a ópalo-CT la inhibe.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- La sedimentología sedimentológica.
- La mineralogía es la Mineralogía.
Sus antecedentes:
- La formación de dolomitas es crucial para comprender la diagenesis de los carbonatos.
- Las condiciones ambientales que rigen la dolomitización siguen siendo un área de investigación clave.
- La diagenesis de sílice puede influir en las transformaciones minerales de carbonato.
Objetivo del estudio:
- Investigar experimentalmente las condiciones que favorecen la formación de dolomitas.
- Para aclarar el papel de la concentración de sulfato y la diagenesis de sílice en la dolomitización.
- Para determinar el impacto de las transformaciones de ópalo-A a ópalo-CT y ópalo-CT a cuarzo en la precipitación de dolomita.
Principales métodos:
- Sustitución experimental de calcita y aragonita bajo condiciones controladas.
- Varias concentraciones de sulfato disuelto.
- Etapas de diagenesis de sílice manipulada, incluidas las transformaciones de ópalo-A, ópalo-CT y cuarzo.
Principales resultados:
- La dolomitización es favorecida por las bajas concentraciones de sulfato disuelto y la limitada diagenesis de sílice contemporánea.
- La reducción de sulfatos microbianos y la mezcla de agua dulce y agua de mar crean condiciones favorables de bajo contenido de sulfatos.
- La transformación de ópalo-A a ópalo-CT inhibe la formación de dolomita, mientras que la transformación de ópalo-CT a cuarzo la promueve.
Conclusiones:
- La dolomitización es viable en ambientes marinos y lacustres bajo condiciones geoquímicas específicas.
- La diagenesis de sílice juega un papel crítico y dependiente del tiempo en el control de la precipitación de dolomita.
- Comprender estos procesos es vital para interpretar las antiguas rocas sedimentarias carbonatadas.
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