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Las restricciones del fluido poroso sobre la temperatura y la composición isotópica de oxígeno del océano glacial
1D. P. Schrag, Department of Geological and Geophysical Sciences, Princeton University, Princeton, NJ 08544-1003, USA. G. Hampt, Institute of Marine Sciences, University of California, Santa Cruz, CA 95064, USA. D. W. Murray, Department of Geological Sciences, Brown University, Providence, RI 02912, USA.
Science (New York, N.Y.)
|June 28, 1996
Resumen
Las temperaturas oceánicas fueron más frías durante el último máximo glacial. El análisis de los isótopos de oxígeno en los fluidos porosos del Atlántico tropical y foraminifera revela una caída de 4 ° C en la temperatura de las aguas profundas, lo que contribuye a las reconstrucciones climáticas.
Área de la Ciencia:
- La paleoceanografía es la paleoceanografía.
- La geoquímica marina es la geoquímica marina.
- Ciencias del clima Ciencias del clima Ciencias del clima Ciencias del clima
Sus antecedentes:
- La reconstrucción de temperaturas oceánicas pasadas es crucial para comprender la dinámica climática.
- Los isótopos de oxígeno en los sedimentos marinos y los fósiles sirven como valiosos indicadores de las condiciones climáticas del pasado.
- El Último Máximo Glacial (LGM, por sus siglas en inglés) representa un período significativo de enfriamiento global.
Objetivo del estudio:
- Para determinar la temperatura de las aguas profundas en el Atlántico tropical durante el LGM.
- Para evaluar la contribución de los cambios en el volumen de hielo a los registros de isótopos de oxígeno.
- Para conciliar las discrepancias entre los diferentes proxies paleoclimáticos.
Principales métodos:
- Análisis de la composición isotópica del oxígeno (delta18O) en fluidos porosos de núcleos de sedimentos de aguas profundas.
- Medición del delta18O en las conchas bentónicas de foraminíferos.
- Integración de los datos de fluidos porosos y foraminiferos con los registros paleoclimáticos existentes.
Principales resultados:
- El delta18O del agua de mar en el Atlántico tropical fue 0.8 ± 0.1 por mil más alto durante el LGM en comparación con el presente.
- Esta relación elevada, combinada con los datos foraminiferales, indica una temperatura del agua profunda 4°C más fría en el Atlántico tropical durante el LGM.
- La contribución estimada del volumen de hielo global a los cambios del delta18O es de 1,0 por mil.
Conclusiones:
- La circulación y la temperatura del océano profundo fueron significativamente diferentes durante el LGM.
- Los hallazgos ayudan a conciliar los datos paleoceanográficos con otros proxies climáticos.
- Este estudio refina nuestra comprensión de la oceanografía del Atlántico tropical durante los períodos glaciales pasados.
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