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Extinción repentina de los dinosaurios: Cretácico más reciente, las Grandes Llanuras superiores, EE.UU
P M Sheehan1, D E Fastovsky, R G Hoffmann
1Department of Geology, Milwaukee Public Museum, WI 53233, USA.
Science (New York, N.Y.)
|November 8, 1991
Resumen
La diversidad de dinosaurios en la Formación Hell Creek no mostró un declive gradual antes de la extinción. Esto sugiere un evento de extinción abrupta, posiblemente causada por el impacto de un asteroide, en lugar de una lenta disminución.
Área de la Ciencia:
- Paleontología Paleontología.
- La estratigrafía es la estratigrafía.
- Diversidad ecológica Diversidad ecológica.
Sus antecedentes:
- La Formación de Hell Creek es un sitio clave para comprender los ecosistemas de dinosaurios al final del período Cretácico.
- Estudios anteriores han debatido la naturaleza del declive de los dinosaurios antes del evento de extinción del Cretácico-Paleógeno.
Objetivo del estudio:
- Para investigar patrones a nivel familiar de la diversidad ecológica de los dinosaurios en la Formación Hell Creek durante un período de tres años.
- Para determinar si hubo una disminución gradual en las poblaciones de dinosaurios antes del final del Cretácico.
Principales métodos:
- Realizó un estudio de campo de tres años en la Formación Hell Creek (Montana y Dakota del Norte).
- Empleó una división tripartita de la formación para la fiabilidad estratigráfica.
- Corregido por sesgos de conservación al comparar ensamblajes fósiles similares.
- Utilizó encuestas y procedimientos de recolección a gran escala y estadísticamente rigurosos.
Principales resultados:
- No se encontró evidencia estadísticamente significativa (P < 0,05) de una disminución gradual de la diversidad ecológica de los dinosaurios.
- Los patrones de diversidad de los dinosaurios se mantuvieron consistentes a través de diferentes niveles estratigráficos dentro de la formación.
Conclusiones:
- Los hallazgos apoyan la hipótesis de un evento de extinción abrupta para los dinosaurios.
- Un impacto extraterrestre, como el impacto de un asteroide, es consistente con la ausencia observada de declive gradual.
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