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Anomalía de iridio aproximadamente sincrónica con las extinciones terminales del eoceno.

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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.

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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.