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Polvo de cometa como fuente de aminoácidos en el límite Cretácico / Terciario
1NASA Ames Research Center, Moffett Field, California 94035, USA.
Nature
|November 8, 1990
Resumen
Los aminoácidos extraterrestres encontrados cerca de la frontera Cretácico / Terciario (K / T) sugieren la deposición de polvo de cometa, no el impacto. Esta teoría explica su presencia por encima y por debajo de la capa límite, y su ausencia en la arcilla de impacto en sí.
Área de la Ciencia:
- Astrobiología Astrobiología.
- La geoquímica es la geoquímica.
- Paleontología Paleontología.
Sus antecedentes:
- Aminoácidos extraterrestres detectados en el límite Cretácico / Terciario (K / T) en Stevns Klint, Dinamarca.
- Aminoácidos que se encuentran en las capas por encima y por debajo de la arcilla límite, pero no dentro de ella.
Objetivo del estudio:
- Investigar el origen y el mecanismo de deposición de aminoácidos extraterrestres en el límite K/T.
- Para conciliar la presencia de aminoácidos con el evento de impacto K/T.
Principales métodos:
- Análisis geoquímico de muestras de roca del límite K/T.
- Comparación de la distribución de aminoácidos con modelos de impacto y de deposición de polvo cometario.
Principales resultados:
- Los aminoácidos están ausentes en la arcilla límite K / T, lo que dificulta la entrega de impactos.
- La presencia de aminoácidos en las capas que flanquean el límite sugiere deposición independiente del evento de impacto principal.
Conclusiones:
- Los aminoácidos extraterrestres en el límite K / T probablemente se originaron del polvo de cometa.
- El polvo cometario, no el propio impactador, entregó estas moléculas prebióticas a la Tierra antes y después del evento de impacto.
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