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Anomalía de iridio aproximadamente sincrónica con las extinciones terminales del eoceno
Science (New York, N.Y.)
|May 21, 1982
Resumen
Una anomalía de iridio y microtektitas sugieren que un gran impacto de bólido ocurrió hace 34 millones de años. Este evento probablemente causó deposición simultánea de iridio y extinciones masivas en radiolarios y mamíferos.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Paleontología Paleontología.
- Estudios de cráteres de impacto Estudios de cráteres de impacto
Sus antecedentes:
- Las anomalías de iridio están vinculadas a impactos extraterrestres.
- Las microtektitas encontradas en los núcleos del Mar Caribe (sitio DSDP 149) están asociadas con el campo de tektita de América del Norte, fechado hace ~34 millones de años.
- Este horizonte de microtektita coincide con la extinción de cinco especies radiolarias.
Objetivo del estudio:
- Para investigar la causa de una anomalía de iridio encontrada en una capa de microtektita.
- Para explorar el vínculo entre la anomalía del iridio, las microtektitas y los posibles eventos de extinción masiva.
Principales métodos:
- Análisis de muestras de núcleo de aguas profundas del sitio del Proyecto de Perforación de Aguas Profundas 149.
- Análisis geoquímico para la concentración de iridio.
- Correlación de las capas de microtektita con los datos geológicos y paleontológicos conocidos.
Principales resultados:
- Se detectó una anomalía de iridio en coincidencia con el nivel de microtektita.
- Es probable que el iridio provenga de una nube de polvo depositada simultáneamente con microtektitas, lo que sugiere un impacto de bólido.
- El evento de impacto data de hace aproximadamente 34 millones de años.
Conclusiones:
- La anomalía del iridio, las tektitas y las microtektitas proporcionan una fuerte evidencia de un gran evento de impacto de bólido hace 34 millones de años.
- Este impacto puede haber desencadenado la extinción de especies radiolarias y contribuido a extinciones masivas en mamíferos terrestres.
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