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Hielo continental en Groenlandia durante el Eoceno y el Oligoceno
James S Eldrett1, Ian C Harding, Paul A Wilson
1School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, European Way, Southampton SO14 3ZH, UK.
Nature
|February 9, 2007
Resumen
Los primeros glaciares de Groenlandia existían 20 millones de años antes de lo que se pensaba, durante la transición Eoceno-Oligoceno. La evidencia de los escombros de las balsas de hielo sugiere hielo glacial, no hielo marino, sedimentos transportados.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- La paleoceanografía es la paleoceanografía.
- Geología Geología Geología.
Sus antecedentes:
- La transición Eoceno-Oligoceno (hace 55-23 millones de años) marcó un cambio climático global significativo de un mundo libre de hielo a uno con capas de hielo antárticas.
- La historia de la glaciación temprana del hemisferio norte sigue siendo controvertida.
- La comprensión previa sugería que la glaciación del hemisferio norte ocurrió más tarde de lo indicado por los nuevos hallazgos.
Objetivo del estudio:
- Investigar el momento y el origen de la glaciación temprana en el hemisferio norte.
- Para proporcionar evidencia de la actividad glacial durante el Eoceno tardío al Oligoceno temprano.
Principales métodos:
- Análisis de escombros estratigráficamente extensos de las balsas de hielo, incluidas las piedras caídas macroscópicas.
- Análisis sedimentológico de muestras del mar de Noruega y Groenlandia.
- La datación de los sedimentos al período comprendido entre hace aproximadamente 38 y 30 millones de años.
Principales resultados:
- Descubrimiento de escombros de balsas de hielo indicativos del transporte glacial en el Eoceno tardío a los sedimentos del Oligoceno temprano (hace 38-30 millones de años).
- Identificación del este de Groenlandia como la fuente probable del material de las balsas de hielo.
- La evidencia sugiere la presencia de glaciares aislados en Groenlandia aproximadamente 20 millones de años antes de lo documentado anteriormente.
Conclusiones:
- Los hallazgos desafían los calendarios existentes para la glaciación del hemisferio norte.
- Los glaciares aislados existieron en Groenlandia durante un período de temperaturas sustancialmente más altas y concentraciones atmosféricas de CO2.
- Esta investigación contribuye a comprender las dinámicas climáticas del Cenozoico temprano y la iniciación de la capa de hielo.
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