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El origen del gran cráter de los meteoritos SNC
Science (New York, N.Y.)
|August 14, 1987
Resumen
Los meteoritos marcianos (SNCs) probablemente se originaron en un cráter de impacto masivo de más de 100 km de ancho, hace aproximadamente 200 millones de años. Su exposición a los rayos cósmicos comenzó mucho más tarde, después de la fragmentación espacial.
Área de la Ciencia:
- Ciencias planetarias Ciencias planetarias.
- Cosmoquímica es la cosmoquímica.
- El cráter de impacto es el cráter de impacto.
Sus antecedentes:
- Se sugiere fuertemente que los meteoritos de Shergottite, nakhlite y Chassigny (SNC) sean de origen marciano.
- Los mecanismos de eyección anteriores para las rocas marcianas carecen de completa satisfacción.
Objetivo del estudio:
- Para investigar historias plausibles de eyección y exposición a rayos cósmicos de los meteoritos SNC.
- Para determinar el escenario de origen más probable para estos meteoritos marcianos.
Principales métodos:
- Utilizó el modelo de espalación Melosh para estimar el tamaño del cráter y las velocidades de eyección.
- Se analizaron las tasas de producción de cráteres marcianos para evaluar la probabilidad de formación de grandes cráteres.
- Examinó historias de exposición a rayos cósmicos basadas en eventos de fragmentación.
Principales resultados:
- Los meteoritos SNC probablemente fueron expulsados de un gran cráter (>100 km de diámetro) hace ~200 millones de años.
- La exposición a rayos cósmicos se inició hace 0,5-10 millones de años después de la fragmentación espacial de los objetos eyectados.
Conclusiones:
- El modelo de eyección por impacto proporciona una explicación plausible para los orígenes de los meteoritos SNC.
- El momento de la eyección y la posterior exposición a rayos cósmicos son eventos distintos.
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