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La transición del Pleistoceno medio en el Pacífico tropical
Martín Medina-Elizalde1, David W Lea
1Department of Earth Science, University of California Santa Barbara, Santa Barbara, CA 93106-9630, USA.
Science (New York, N.Y.)
|October 15, 2005
Resumen
Los cambios climáticos del Pleistoceno medio muestran oscilaciones de la temperatura de la superficie del mar (SST) que cambian de 41,000 a 100,000 ciclos de años. Estos cambios en el SST del Pacífico tropical precedieron a los cambios en el volumen de hielo, implicando el dióxido de carbono atmosférico como un factor clave.
Área de la Ciencia:
- La paleoceanografía es la paleoceanografía.
- Ciencias del clima Ciencias del clima Ciencias del clima
- Geología marina Geología marina.
Sus antecedentes:
- La transición del Pleistoceno medio (MPT) marca un cambio significativo en la periodicidad del ciclo glacial-interglacial de la Tierra.
- Comprender los impulsores de este cambio de periodicidad es crucial para predecir las dinámicas climáticas futuras.
Objetivo del estudio:
- Para reconstruir las temperaturas pasadas de la superficie del mar (SST) en la piscina cálida del Pacífico ecuatorial occidental durante el MPT.
- Investigar la relación entre las SST tropicales del Pacífico, las SST de lengua fría del Pacífico oriental y los cambios en el volumen del hielo continental.
Principales métodos:
- Análisis de las proporciones de magnesio/calcio foraminiferal planctónico para establecer un registro de SST.
- Datación de núcleos de sedimentos para establecer una línea de tiempo precisa para los eventos paleoclimáticos.
Principales resultados:
- Los registros de SST revelan un cambio en la periodicidad de oscilación glacial-interglacial de 41.000 a 100.000 años en el MPT, hace aproximadamente 950.000 años.
- Los cambios en el SST del Pacífico tropical fueron sincronizados con los SST de lengua fría del Pacífico oriental, pero condujeron a cambios en el volumen de hielo continental.
Conclusiones:
- El tiempo y la naturaleza observados de los cambios de la SST del Pacífico tropical sugieren un cambio en la periodicidad del forzamiento radiativo por el dióxido de carbono atmosférico.
- Este desplazamiento forzoso de CO2 está implicado como la causa principal del cambio en las periodicidades climáticas durante la transición del Pleistoceno medio.
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