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Isótopos de estroncio en el agua de mar, lluvia ácida y la frontera entre el Cretácico y el Terciario
Science (New York, N.Y.)
|January 29, 1988
Resumen
Un impacto masivo de un asteroide desencadenó cambios atmosféricos, lo que condujo a lluvias ácidas y un aumento de la intemperie continental. Este evento geológico probablemente explica las altas proporciones de isótopos de estroncio observadas en el agua de mar antigua.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Paleoclimatología Paleoclimatología
- El cráter de impacto es el cráter de impacto.
Sus antecedentes:
- El período final del Cretácico está marcado por importantes cambios geológicos y ambientales.
- Las proporciones de isótopos de estroncio en el agua de mar proporcionan un registro de la intemperie continental y los procesos de la corteza.
Objetivo del estudio:
- Para investigar el vínculo entre los impactos de grandes bólidos y los cambios geoquímicos en los sistemas de la Tierra.
- Para explicar las altas proporciones de estroncio-87/estroncio-86 observadas en el agua de mar durante el Cretácico tardío.
Principales métodos:
- Modelado de calentamiento por choque atmosférico y reacciones químicas posteriores.
- Analizando los efectos de la precipitación ácida en el clima continental.
- Correlación de la intemperie inducida por el impacto con los registros de isótopos marinos de estroncio.
Principales resultados:
- Los impactos de bolido generan significativos óxidos de nitrógeno a través del calentamiento de choque atmosférico.
- Las precipitaciones ácidas resultantes de los eventos de impacto aumentan drásticamente la intemperie continental.
- El aumento de la intemperie libera grandes cantidades de estroncio de la corteza continental a los océanos, elevando las proporciones de agua de mar 87Sr/86Sr.
Conclusiones:
- Los impactos de grandes bólidos son un desencadenante plausible para la excursión de isótopos de estroncio del Cretácico tardío observada.
- Similares picos en el registro de isótopos de estroncio en otros momentos pueden indicar otros eventos de impacto o episodios de intemperie intensa.
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