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Perturbación del ecosistema de plantas terrestres en el límite entre el Cretácico y el Terciario, interior occidental
Science (New York, N.Y.)
|September 7, 1984
Resumen
El límite entre el Cretácico y el Terciario en América del Norte muestra una clara capa de arcilla rica en iridio. Esta capa marca un cambio repentino del ecosistema, lo que indica un evento catastrófico en todo el continente.
Área de la Ciencia:
- Paleontología Paleontología.
- Geología Geología Geología.
- Ecología Ecología Ecología.
Sus antecedentes:
- El límite Cretácico-Terciario (K-Pg) marca una transición significativa en la historia de la Tierra.
- Este límite a menudo se identifica mediante marcadores geológicos y registros fósiles.
- Estudios anteriores han investigado los eventos del límite K-Pg en varias regiones.
Objetivo del estudio:
- Para definir las características palinológicas del límite Cretácico-Terciario en el oeste de América del Norte.
- Para investigar el impacto ecológico del evento en el límite K-Pg.
- Para inferir la escala y la naturaleza de la interrupción basada en la evidencia fósil.
Principales métodos:
- Análisis palinológico de núcleos de sedimentos del interior occidental de América del Norte.
- Identificación y cuantificación de los conjuntos de polen y esporas a través de la capa límite.
- Análisis geoquímico de la capa de arcilla rica en iridio.
Principales resultados:
- El límite entre el Cretácico y el Terciario se encuentra precisamente en la parte superior de una capa de arcilla rica en iridio.
- Se observó una desaparición abrupta de especies específicas de polen.
- Un cambio rápido y significativo en la proporción de esporas de helecho a polen de angiospermas se produjo inmediatamente después del evento límite.
Conclusiones:
- Los cambios palinológicos observados indican una interrupción continental de los ecosistemas terrestres.
- El cambio ecológico geológicamente breve pero pronunciado sugiere un evento catastrófico mayor.
- Estos hallazgos apoyan la hipótesis de un impacto o evento a gran escala al final del período Cretácico.
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