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Evidencia geoquímica de una lluvia de cometas en el Eoceno tardío
K A Farley1, A Montanari, E M Shoemaker
1Division of Geological and Planetary Sciences, California Institute of Technology, MS 170-25, Pasadena, CA 91125, USA. farley@gps.caltech.edu
Science (New York, N.Y.)
|June 20, 1998
Resumen
La Tierra experimentó un aumento del helio-3 extraterrestre, un rastreador de polvo, durante el Eoceno tardío. Este flujo de 2,5 millones de años coincidió con los principales impactos de asteroides, lo que sugiere una breve mejora en el polvo del sistema solar y los objetos que cruzan la Tierra.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Ciencias planetarias Ciencias planetarias.
- Paleoclimatología Paleoclimatología
Sus antecedentes:
- Las piedras calizas pelágicas contienen helio-3 extraterrestre, un trazador para el polvo interplanetario.
- Los principales eventos de impacto, como los cráteres de Popigai y Chesapeake Bay, ocurrieron hace aproximadamente 36 millones de años.
- La época del Eoceno tardío experimentó eventos geológicos y astronómicos significativos.
Objetivo del estudio:
- Para analizar las piedras calizas pelágicas en busca de concentraciones extraterrestres de helio-3.
- Para correlacionar el flujo de helio-3 con los principales eventos de impacto en la historia de la Tierra.
- Para investigar la dinámica de los objetos que cruzan la Tierra y el polvo del sistema solar interior.
Principales métodos:
- Análisis geoquímico de muestras de piedra caliza pelágica.
- Análisis isotópico para cuantificar las concentraciones de helio-3.
- Datación cronológica para establecer relaciones temporales entre eventos.
Principales resultados:
- Se identificó un período de 2,5 millones de años (My) de flujo de helio-3 extraterrestre mejorado a finales del Eoceno.
- La mejora del helio-3 comenzó ~1 My antes y terminó ~1.5 My después de los eventos de impacto de Popigai y Chesapeake Bay.
- El aumento de las concentraciones de helio-3 se correlacionó con grandes eventos de impacto, lo que indica una mejora simultánea y breve de los objetos que cruzan la Tierra y el polvo del sistema solar interior.
Conclusiones:
- La correlación simultánea sugiere una lluvia de cometas provocada por una perturbación de la nube de Oort.
- Los objetos que cruzan la Tierra y el polvo interplanetario experimentaron un aumento transitorio durante el Eoceno tardío.
- Este evento proporciona evidencia de procesos dinámicos dentro del sistema solar que afectan a la Tierra.
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