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Reconstrucción palinspástica pre-mesozóica de la gran cuenca oriental (oeste de los Estados Unidos)
Science (New York, N.Y.)
|September 29, 1989
Resumen
La Gran Cuenca experimentó un importante acortamiento y extensión de la corteza terrestre, lo que requirió reconstrucciones geológicas revisadas. Un nuevo análisis revela al menos 104-135 km de acortamiento y 250 km de extensión, remodelando nuestra comprensión de su cuenca del Proterozoico al Cámbrico Temprano.
Área de la Ciencia:
- Geología Geología Geología.
- La tectónica es la tectónica.
- Geología Estructural Geología estructural.
Sus antecedentes:
- La Gran Cuenca es crucial para entender la geología Proterozoica y Paleozoica y la mecánica de la corteza.
- Las reconstrucciones anteriores de la historia de deformación del Mesozoico y Cenozoico necesitan revisión debido a nuevos datos.
Objetivo del estudio:
- Desarrollar una nueva reconstrucción palinspática para las rocas del Proterozoico medio al Cámbrico Temprano de la Gran Cuenca.
- Integrar nuevos hallazgos sobre el acortamiento y la extensión de la corteza del Mesozoico-Cenozoico para un contexto regional preciso.
Principales métodos:
- Análisis de la evidencia geológica para el acortamiento de la corteza terrestre a través de empujes y pliegues vergentes al este.
- Datos paleomagnéticos para restringir la dirección y magnitud de la extensión desde finales del Mesozoico.
- Las incertidumbres geológicas y paleomagnéticas se utilizaron para estimar las variaciones de extensión con la latitud.
Principales resultados:
- El acortamiento total de la corteza terrestre se estima en 104 a 135 kilómetros.
- Aproximadamente 250 kilómetros de extensión se produjeron en la Gran Cuenca.
- La anchura original de la cuenca del Proterozoico y el Cámbrico Temprano era de 150 a 300 kilómetros, orientada más hacia el norte-sur.
Conclusiones:
- Las reconstrucciones revisadas son necesarias para la historia geológica de la Gran Cuenca.
- La región experimentó un considerable acortamiento y extensión, alterando significativamente su paleogeografía.
- Los datos paleomagnéticos admiten una rotación mínima de Sierra Nevada, lo que simplifica los cálculos de extensión.
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