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El ascenso de los dinosaurios está vinculado a una anomalía de iridio en el límite triásico-jurásico
P E Olsen1, D V Kent, H-D Sues
1Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.
Science (New York, N.Y.)
|May 23, 2002
Resumen
Los grandes dinosaurios terópodos se diversificaron rápidamente después del evento de extinción del Triásico-Jurásico, probablemente causado por un impacto de bólido. Este evento estableció ecosistemas dominados por dinosaurios que persistieron durante 135 millones de años.
Área de la Ciencia:
- Paleontología Paleontología.
- Geología Geología Geología.
- Paleobiología de dinosaurios Paleobiología de dinosaurios.
Sus antecedentes:
- El límite Triásico-Jurásico (T-J) marca un período significativo de extinción y rotación de la fauna.
- Comprender el momento y los impulsores de la aparición de los dinosaurios es crucial para comprender los ecosistemas del Mesozoico.
Objetivo del estudio:
- Para analizar la relación temporal entre la aparición de grandes dinosaurios terópodos y la extinción masiva T-J.
- Para investigar el impacto extraterrestre potencial como la causa de este evento de extinción.
Principales métodos:
- Análisis de huellas de tetrápodos y material esquelético de más de 70 localidades de América del Norte.
- Análisis geoquímico para las anomalías de iridio.
- Análisis palinológico (conteo de esporas) para detectar cambios ambientales.
Principales resultados:
- Los grandes dinosaurios terópodos aparecieron <10.000 años después del límite T-J y <30.000 años después de los últimos taxones del Triásico.
- Esta rápida rotación coincidió con una extinción masiva terrestre, una anomalía de iridio y un pico de esporas de helecho.
- La diversidad de dinosaurios se estabilizó dentro de los 100.000 años posteriores al límite, estableciendo el dominio de los dinosaurios.
Conclusiones:
- Se sugiere fuertemente un impacto de bólido como la causa de la extinción masiva T-J y la posterior radiación de terópodos.
- El evento del límite T-J condujo al establecimiento de ecosistemas dominados por dinosaurios de larga duración en el este de América del Norte.
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