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Datando el crecimiento de la corteza oceánica en una cresta de expansión lenta
Joshua J Schwartz1, Barbara E John, Michael J Cheadle
1Department of Geology and Geophysics, University of Wyoming, Laramie, WY 82071, USA.
Science (New York, N.Y.)
|October 29, 2005
Resumen
La datación con uranio-plomo-zircón de los gabros del Banco de la Atlántida revela información sobre la formación de la corteza oceánica. Algunos gabros se formaron en la edad prevista del fondo marino, mientras que otros sugieren una cristalización más profunda y más antigua dentro de la litosfera.
Área de la Ciencia:
- Geología Geología Geología.
- La geoquímica es la geoquímica.
- La tectónica es la tectónica.
Sus antecedentes:
- La formación de la corteza oceánica en las crestas de expansión lenta es compleja.
- Comprender los procesos de crecimiento de la corteza es crucial para la tectónica de placas.
Objetivo del estudio:
- Para restringir el tiempo y los mecanismos de crecimiento de la corteza oceánica en la cordillera suroeste de la India.
- Para investigar el origen de los gabros anómalmente viejos en la corteza oceánica inferior.
Principales métodos:
- Datamiento de uranio-plomo-zircón de los gabros de la corteza inferior.
- Análisis de muestras de gabbro de Atlantis Bank, en el suroeste de la cordillera de las Indias.
Principales resultados:
- Se obtuvieron diecinueve edades de uranio-plomo-zircón para gabbros.
- Aproximadamente el 75% de los gabros se acrecentaron cerca de la edad magnética prevista del fondo marino.
- Aproximadamente el 25% de los gabros obtuvieron edades significativamente mayores de lo previsto.
Conclusiones:
- Los hallazgos sugieren una combinación de acreción en el eje y una cristalización más profunda y más antigua para los componentes de la corteza oceánica.
- Gabros anómalamente viejos probablemente se formaron a profundidades de 5-18 km por debajo de la corteza y luego se elevaron.
- Este estudio refina los modelos de construcción de la corteza oceánica en centros de expansión lenta.
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