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Colapso de la Corriente de California durante máximos glaciales vinculados al cambio climático en la tierra
T D Herbert1, J D Schuffert, D Andreasen
1Department of Geological Sciences, Brown University, Providence, RI 02912, USA.
Science (New York, N.Y.)
|July 7, 2001
Resumen
Las temperaturas de la superficie del mar (SST) a lo largo de la costa de California han fluctuado significativamente en los últimos 550.000 años. El calentamiento glacial indicó un debilitamiento de la Corriente de California, apoyando el forzamiento orbital de las edades de hielo.
Área de la Ciencia:
- La paleoceanografía es la paleoceanografía.
- Geología marina Geología marina.
- Ciencias del clima Ciencias del clima Ciencias del clima
Sus antecedentes:
- Los índices de insaturación de alquenonas proporcionan un sustituto para reconstruir las temperaturas pasadas de la superficie del mar (SST).
- El sistema de la Corriente de California juega un papel crucial en la regulación climática regional.
- Comprender los ciclos glaciar-interglaciar es clave para comprender la dinámica climática a largo plazo.
Objetivo del estudio:
- Para reconstruir las temperaturas pasadas de la superficie del mar (SST) a lo largo del margen de California en los últimos 550.000 años.
- Para investigar la relación entre los cambios del SST, la dinámica de la corriente de California y los ciclos glaciales.
- Evaluar la aplicabilidad regional frente a la global de los registros paleoclimáticos.
Principales métodos:
- Análisis de los índices de insaturación de alquenonas de núcleos de sedimentos marinos.
- Análisis del polen para identificar cambios en la vegetación indicativos de cambios climáticos.
- Correlación de los registros del SST con datos paleoclimáticos y mecanismos de forzamiento orbital.
Principales resultados:
- Las SST reconstruidas muestran grandes fluctuaciones glaciales-interglaciales (4-8°C) durante 550.000 años.
- Los períodos interglaciales pico se correlacionan con el polen de la secoya, lo que indica la presencia de bosques tropicales templados.
- Las SST se calentaron 10.000-15.000 años antes de la deglaciación en la región de la Corriente de California, vinculada a corrientes debilitadas y sistemas de viento alterados.
Conclusiones:
- El calentamiento glacial a lo largo del margen de California es una señal regional del debilitamiento de la corriente de California.
- El registro de calcita de Devils Hole refleja las paleotemperaturas regionales, no globales.
- Estos hallazgos apoyan la teoría orbital (Milankovitch) de las edades de hielo.
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