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La temperatura de las profundidades marinas y los cambios en el volumen de hielo a través de las transiciones
Sindia Sosdian1, Yair Rosenthal
1Institute of Marine and Coastal Science and Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ 08901, USA. sindia.sosdian@anu.edu.au
Science (New York, N.Y.)
|July 18, 2009
Resumen
Las temperaturas de los océanos profundos influyeron significativamente en las transiciones climáticas de la Tierra, incluido el desarrollo de las capas de hielo del hemisferio norte. Estos cambios de temperatura explican una gran parte del registro global de isótopos de oxígeno durante el Plioceno tardío y el Pleistoceno medio.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- Oceanografía La oceanografía es la oceanografía.
- Geología Geología Geología.
Sus antecedentes:
- El sistema climático de la Tierra ha experimentado transformaciones significativas desde finales del Plioceno.
- El desarrollo y la intensificación de las capas de hielo del hemisferio norte son características clave de este período.
- Los isótopos de oxígeno bentónico foraminiferal (delta18Ob) son los principales indicadores de estos cambios climáticos.
Objetivo del estudio:
- Para reconstruir las variaciones de temperatura del océano profundo durante las transiciones climáticas clave.
- Para determinar la contribución de los cambios de temperatura a la señal global de delta18Ob.
- Para investigar los impulsores de la dinámica de las capas de hielo del hemisferio norte.
Principales métodos:
- Análisis de las proporciones bentónicas foraminiferales de magnesio/calcio (Mg/Ca) del Atlántico Norte.
- Generación de un registro de temperatura de los océanos profundos con resolución orbital.
- Comparación de los datos de temperatura con el registro del isótopo de oxígeno bentónico foraminiferal (delta18Ob).
Principales resultados:
- Las variaciones de temperatura de los océanos profundos constituyen un componente sustancial de la señal global delta18Ob.
- Se identificaron dos eventos de enfriamiento prominentes: la transición del Plioceno tardío (LPT, 2.5-3 Ma) y la transición del Pleistoceno medio (MPT, 1.2-0.85 Ma).
- El aumento del volumen de hielo LPT está relacionado con el enfriamiento global, mientras que el cambio de MPT a ciclos de 100.000 años sugiere una dinámica alterada de la capa de hielo.
Conclusiones:
- La temperatura del océano profundo es un factor crítico para comprender el cambio climático del Plioceno tardío y el Pleistoceno medio.
- El cambio de ciclicidad del MPT indica una compleja interacción entre el enfriamiento global y el comportamiento de las capas de hielo.
- La paleotermometría Mg/Ca proporciona información valiosa sobre la variabilidad climática pasada y la evolución de las capas de hielo.
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