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Variaciones isotópicas del estroncio en el agua de mar desde hace 2,5 millones de años hasta el presente
Science (New York, N.Y.)
|July 6, 1990
Resumen
El análisis de carbonatos marinos revela un aumento significativo en las proporciones de isótopos de estroncio en el agua de mar en los últimos 2,5 millones de años. Esto sugiere tasas de intemperie continental excepcionalmente altas y fluctuantes, potencialmente relacionadas con los cambios climáticos.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- La paleoceanografía es la paleoceanografía.
- Ciencias del clima Ciencias del clima Ciencias del clima Ciencias del clima
Sus antecedentes:
- La relación de isótopos de estroncio ((87) Sr / ((86) Sr) en los carbonatos marinos sirve como un sustituto para los procesos climáticos globales.
- Comprender las variaciones pasadas en el clima es crucial para interpretar la química del océano y la dinámica climática.
Objetivo del estudio:
- Para reconstruir la historia del agua de mar durante los últimos 2,5 millones de años.
- Para inferir las fluctuaciones en las tasas de intemperie continental durante este período.
- Investigar posibles vínculos entre los cambios climáticos y los eventos paleoclimáticos.
Principales métodos:
- Análisis de muestras de carbonato marino para determinar la relación (87) Sr/ (86) Sr.
- Datación geoquímica de muestras de carbonato para establecer un marco temporal.
- Correlación de las proxies de la tasa de desgaste con los indicadores paleoclimáticos como los isótopos de oxígeno y la preservación de carbonatos.
Principales resultados:
- Se observó un marcado aumento de 14 x 10 ((-5) en la proporción de agua de mar (87) Sr / (86) Sr en los últimos 2,5 millones de años.
- La tasa promedio de aumento indica una excepcionalmente alta intemperie continental.
- Se encontraron evidencias de fluctuaciones significativas en las tasas de intemperie, que varían hasta en un +/-30% de los valores actuales.
Conclusiones:
- Las altas tasas de desgaste continental caracterizaron los últimos 2,5 millones de años.
- Los cambios observados en la intensidad de la intemperie parecen coincidir con los cambios paleoclimáticos documentados.
- El estudio destaca la interconexión de la actividad tectónica, el clima, la química de los océanos y el clima global.
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