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La evidencia de múltiples fuentes de diamantes de las condritas primitivas
Science (New York, N.Y.)
|November 22, 1991
Resumen
Los diamantes de grano fino en los meteoritos muestran variaciones en los isótopos de carbono y nitrógeno vinculados a su tipo de meteorito anfitrión. Estas diferencias intrínsecas sugieren una distribución heterogénea en la nebulosa solar temprana.
Área de la Ciencia:
- Cosmoquímica es la cosmoquímica.
- Ciencias planetarias Ciencias planetarias.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Los diamantes de grano fino son el polvo circunstelar abundante que se encuentra en los meteoritos primitivos.
- Sus composiciones elementales e isotópicas están influenciadas por el meteorito anfitrión.
- Estudios anteriores observaron variaciones en las propiedades del diamante, pero carecían de explicaciones definitivas.
Objetivo del estudio:
- Para investigar las características elementales e isotópicas de diamantes de grano fino de diferentes tipos de meteoritos.
- Para determinar la causa de las variaciones en el contenido de nitrógeno y la composición isotópica de carbono.
- Para entender la formación y distribución de estos diamantes en la nebulosa solar temprana.
Principales métodos:
- Aislamiento de diamantes de grano fino de las condritas ordinarias y del tipo CM2.
- Análisis de las composiciones isotópicas de carbono y nitrógeno.
- Experimentos de combustión para estudiar la evolución de la relación carbono-nitrógeno.
Principales resultados:
- Las composiciones isotópicas de carbono oscilaron entre -32 y -38 por mili.
- La abundancia de nitrógeno varió significativamente (0,2 a 0,9 por ciento en peso) entre los tipos de meteoritos.
- Se descartó la desgasificación metamórfica como la causa principal de las diferencias de nitrógeno.
Conclusiones:
- Las variaciones observadas en la composición del diamante son probablemente heredadas de su formación.
- Los diamantes se distribuyeron de manera heterogénea dentro de la nebulosa solar durante la condensación.
- Un portador oculto de nitrógeno dentro del diamante no puede ser excluido como un factor contribuyente.
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