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Una capa de eyección de impacto del Triásico tardío en el suroeste de Gran Bretaña
Gordon Walkden1, Julian Parker, Simon Kelley
1Department of Geology and Petroleum Geology, Kings College, University of Aberdeen, Aberdeen AB24 3UD, UK. spherules@abdn.ac.uk
Science (New York, N.Y.)
|November 16, 2002
Resumen
Los investigadores descubrieron una capa de eyecciones de impacto del Triásico en Gran Bretaña que contiene esférulas y cuarzo sacudido. Este hallazgo proporciona evidencia crucial de impactos extraterrestres durante la era Mesozoica.
Área de la Ciencia:
- Geología Geología Geología.
- Ciencias planetarias Ciencias planetarias.
- Paleontología Paleontología.
Sus antecedentes:
- Los cráteres de impacto terrestres están bien documentados, pero los depósitos de eyección distal asociados son raros en los registros sedimentarios.
- Comprender los eventos de impacto requiere identificar y caracterizar sus capas de eyección.
Objetivo del estudio:
- Para informar sobre el descubrimiento de un importante depósito de eyecciones de impacto del Triásico en el suroeste de Gran Bretaña.
- Datar la capa de eyección y correlacionarla con estructuras de impacto conocidas.
- Analizar las implicaciones de este descubrimiento para comprender los impactos y extinciones del Mesozoico.
Principales métodos:
- Trabajo de campo geológico en el suroeste de Gran Bretaña para identificar y tomar muestras de depósitos sedimentarios.
- Análisis microscópico para identificar esferulas de impacto características y cuarzo sacudido.
- La datación argón-argon del feldespato de potasio dentro de la capa de eyección.
Principales resultados:
- Identificación de un depósito sedimentario del Triásico que contiene esferulas y cuarzo de choque, indicativo de una capa de eyección de impacto.
- La datación argón-argon dio una edad de 214 +/- 2,5 millones de años para el depósito.
- La edad se alinea con varios cráteres de impacto del Triásico, en particular Manicouagan y Rochechouart.
Conclusiones:
- El depósito descubierto representa un raro registro sedimentario de un impacto extraterrestre del Mesozoico.
- Este hallazgo ayuda a descifrar la frecuencia, los efectos y la dinámica de los eventos de impacto.
- Investigaciones adicionales pueden explorar la relación entre esta capa de eyección y el momento de las extinciones de fósiles.
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