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Crisis de la vida del Pérmico-Triásico en la tierra
Science (New York, N.Y.)
|January 6, 1995
Resumen
La datación radiométrica redefine el límite Pérmico-Triásico en Australia, revelando una importante extinción de la flora y una baja diversidad de vegetación del Triásico temprano. La recuperación a los niveles de diversidad del Pérmico tomó millones de años.
Área de la Ciencia:
- La paleobotánica es la paleobotánica.
- Geocronología Geocronología.
- La estratigrafía es la estratigrafía.
Sus antecedentes:
- El límite entre el Pérmico y el Triásico (hace 251 millones de años) marca un importante evento de extinción.
- La comprensión anterior de la ubicación de este límite en la cuenca de Sídney requería una revisión.
Objetivo del estudio:
- Reevaluar la ubicación del límite Pérmico-Triásico en la cuenca de Sydney utilizando técnicas avanzadas de datación.
- Para analizar el impacto de este evento límite en la flora australiana.
Principales métodos:
- Datación radiométrica de las secuencias sedimentarias.
- Estratigrafía isotópica para la definición precisa de los límites.
Principales resultados:
- El límite Pérmico-Triásico se reposiciona dentro de la secuencia sedimentaria de la Cuenca de Sídney.
- En este límite se produjo una disminución significativa en la diversidad floral y el provincialismo.
- La extinción de la flora de los Glossopteris.
- La vegetación del Triásico temprano estaba dominada por licópodos y coníferas voltziales.
- La flora de Dicroidium surgió después de la frontera, pero la recuperación completa de la diversidad y la provincialidad se retrasó hasta el Triásico Medio (hace 244 millones de años).
Conclusiones:
- Los nuevos métodos de datación requieren una comprensión revisada del límite Pérmico-Triásico en el sureste de Australia.
- El evento fronterizo causó un período prolongado de baja diversidad floral y provincialismo.
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