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Litosfera de fundación fotografiada debajo del sur de Sierra Nevada, California, EE.UU
Oliver S Boyd1, Craig H Jones, Anne F Sheehan
1Department of Geological Sciences, University of Colorado at Boulder, 2200 Colorado Avenue, Boulder, CO 80309-0399, USA. oliver.boyd@colorado.edu
Science (New York, N.Y.)
|August 3, 2004
Resumen
La tomografía sísmica muestra la litosfera profunda, incluida la eclogita y la peridotita de granate, descendiendo por debajo de la Sierra Nevada. Esto revela un proceso de eliminación litosférica coherente en la región.
Área de la Ciencia:
- La geofísica es la geofísica.
- Sismología Sismología Sismología.
- La tectónica es la tectónica.
Sus antecedentes:
- La cordillera de Sierra Nevada tiene una historia geológica compleja.
- Comprender la estructura y la dinámica litosférica es crucial para la tectónica de placas.
Objetivo del estudio:
- Para investigar la estructura litosférica profunda bajo el sureste de Sierra Nevada.
- Para caracterizar la composición y la geometría de la litosfera descendente.
Principales métodos:
- Se empleó tomografía sísmica para obtener imágenes de estructuras subterráneas.
- Análisis de las velocidades de las ondas sísmicas para inferir las propiedades de los materiales.
Principales resultados:
- Se observa que la corteza rica en granados y la litosfera del manto descienden hacia el manto superior.
- La litosfera descendente comprende dos capas distintas: la eclogita rica en hierro que cubre el granate rico en magnesio peridotita.
- La eclogita descendente está situada por encima de material previamente identificado de alta velocidad de onda P en el sur del Gran Valle.
Conclusiones:
- Los hallazgos sugieren una coherencia previamente no reconocida en el proceso de eliminación litosférica debajo de la Sierra Nevada y el Gran Valle.
- Este estudio proporciona nuevos conocimientos sobre la subducción y asimilación de la litosfera continental.
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