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Las edades isotópicas de plomo de los condrules y las inclusiones ricas en calcio y aluminio
Yuri Amelin1, Alexander N Krot, Ian D Hutcheon
1Department of Earth Sciences, Royal Ontario Museum, Toronto, ON M5S 2C6, Canada. yamelin@NRCan.gc.ca
Science (New York, N.Y.)
|September 7, 2002
Resumen
La formación de inclusiones ricas en calcio y aluminio (CAI) y condrules en meteoritos ocurrió durante millones de años. Este estudio proporciona restricciones de edad precisas para estos primeros eventos del sistema solar.
Área de la Ciencia:
- Cosmoquímica es la cosmoquímica.
- Ciencias planetarias Ciencias planetarias.
- Geocronología Geocronología.
Sus antecedentes:
- Las inclusiones ricas en calcio y aluminio (CAI) y las cóndrulas son componentes primitivos de los meteoritos.
- Comprender su línea de tiempo de formación es crucial para desentrañar los primeros procesos del sistema solar.
Objetivo del estudio:
- Para determinar con precisión el intervalo de edad entre la formación de CAIs en condritas CV y condrulas en condritas CR.
- Para limitar la duración de los eventos de formación de CAI y condrules en el sistema solar temprano.
Principales métodos:
- Datamiento isocrónico plomo-plomo de cóndrulos en el meteorito Acfer 059.
- Datación isotópica del plomo de las CAI en el meteorito de Efremovka.
- Análisis de las proporciones iniciales de 26Al/27Al.
Principales resultados:
- La edad isócrona plomo-plomo de las cóndrulas CR es de 4564.7 ± 0.6 Ma.
- La edad isotópica del plomo de los ICAC de CV es de 4567,2 ± 0,6 Ma.
- Esto indica un intervalo de 2,5 ± 1,2 millones de años (My) entre la formación de condrules CV CAI y CR, con eventos que duran al menos 1,3 My.
Conclusiones:
- CAI y la formación de cóndrulos abarcó un período significativo en el sistema solar temprano.
- Los intervalos de tiempo determinados son consistentes con las cronologías basadas en la sistemática 26Al-26Mg.
- Esto apoya la importancia cronológica de las relaciones de isótopos 26Al-26Mg en la datación de materiales del sistema solar.
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