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Las plataformas de hielo en el océano Ártico del Pleistoceno inferidas de las formas de lecho glaciogénico de aguas
L Polyak1, M H Edwards, B J Coakley
1Byrd Polar Research Center, Ohio State University, Columbus, Ohio 43210, USA. polyak.l@osu.edu
Nature
|March 22, 2001
Resumen
Las glaciaciones del Pleistoceno probablemente formaron gruesas plataformas de hielo sobre el Océano Ártico, no solo hielo marino. La cartografía geofísica reveló una extensa limpieza glacial y características del lecho marino que apoyan esta hipótesis de la plataforma de hielo.
Área de la Ciencia:
- Geología Geología Geología.
- Oceanografía La oceanografía es la oceanografía.
- Paleoclimatología Paleoclimatología
Sus antecedentes:
- La visión predominante: el Océano Ártico cubierto de hielo marino y icebergs durante las glaciaciones del Pleistoceno.
- Hipótesis contrastante: Una gruesa capa de hielo (≥1 km) cubrió el Océano Ártico.
- La reconstrucción de la historia glacial requiere un mapeo detallado del fondo marino, que es limitado en el Ártico.
Objetivo del estudio:
- Para investigar la presencia y extensión de las capas de hielo del Pleistoceno en el Océano Ártico.
- Para resolver el debate entre la capa de hielo marino perenne frente a una gruesa capa de hielo.
- Para analizar datos geofísicos en busca de evidencia de actividad glacial en el lecho marino del Ártico.
Principales métodos:
- Utilizó un sistema de mapeo geofísico durante la expedición submarina SCICEX de 1999.
- Analizó imágenes de retrodispersión y registros de perfiles subterráneos desde profundidades de hasta 1 kilómetro.
- Mapeó grandes porciones del fondo marino del Océano Ártico.
Principales resultados:
- Identificó múltiples formas de lecho del fondo marino indicativas de limpieza y moldeo glacial.
- Se observó una erosión a gran escala de las crestas de las cordilleras submarinas.
- Las distintas características glaciogénicas proporcionan evidencia de la actividad pasada de la plataforma de hielo.
Conclusiones:
- Inmensas plataformas de hielo de tipo antártico, de hasta 1 km de espesor y cientos de km de largo, existieron en el Océano Ártico durante las glaciaciones del Pleistoceno.
- Estos hallazgos desafían la visión tradicional de la cubierta glacial del Océano Ártico.
- La geomorfología del fondo marino es un indicador clave de la dinámica glacial pasada en los océanos polares.
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