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La entrada de agua de deshielo en el océano meridional durante el último máximo glacial
Science (New York, N.Y.)
|December 2, 1994
Resumen
Las capas de agua de deshielo del Océano Austral durante el último máximo glacial condujeron a isótopos de oxígeno agotados en la sílice de diatomeas. Esto indica un aumento de la entrada de agua de deshielo de la Antártida o de los icebergs, lo que afecta a los ciclos climáticos pasados.
Área de la Ciencia:
- La paleoceanografía es la paleoceanografía.
- Geología marina Geología marina.
- La geoquímica de los isótopos es una geoquímica de isótopos.
Sus antecedentes:
- Los registros de isótopos de oxígeno en los sedimentos marinos proporcionan información sobre las condiciones y el clima del océano en el pasado.
- La sílice biogénica, particularmente los frustules de diatomeas, puede preservar las señales geoquímicas de las aguas superficiales.
Objetivo del estudio:
- Investigar la fuente y las implicaciones del ópalo diatomáceo empobrecido isotópicamente encontrado en núcleos de sedimentos del Océano Austral.
- Reconstruir las contribuciones de agua de deshielo al Océano Antártico durante el último máximo glacial y los ciclos climáticos anteriores.
Principales métodos:
- Análisis de isótopos de oxígeno en sílice biogénica extraída de núcleos de sedimentos de aguas profundas.
- Examen estratigráfico de núcleos de sedimentos de los sectores Atlántico e Indico del Océano Austral.
Principales resultados:
- Descubrimiento de valores de isótopos de oxígeno significativamente agotados en el ópalo diatomeado desde el último máximo glacial.
- Correlación del agotamiento isotópico con la evidencia de la influencia del agua de deshielo en las aguas superficiales en regiones específicas del Océano Antártico.
- Observación de tendencias isotópicas similares en núcleos de sedimentos de ciclos climáticos más antiguos.
Conclusiones:
- Las tapas de agua de deshielo, originadas por el drenaje de la capa de hielo antártica o el transporte de icebergs, estaban presentes en el océano austral glacial.
- Estas entradas de agua de fusión alteraron la composición isotópica de las aguas superficiales, según lo registrado por las diatomeas.
- Los hallazgos destacan la sensibilidad de la circulación del Océano Antártico y la composición isotópica a la descarga de agua de deshielo glacial durante múltiples ciclos climáticos.
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