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Las variaciones de intensidad del campo paleomagnético sugieren la nucleación del núcleo interno del Mesoproterozoico
A J Biggin1, E J Piispa2, L J Pesonen3
1Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool L69 7ZE, UK.
Nature
|October 10, 2015
Resumen
El núcleo interno de la Tierra comenzó a crecer hace aproximadamente 1 a 1.5 mil millones de años, marcando un momento clave en la evolución planetaria. Este hallazgo, basado en datos paleomagnéticos, apoya un modelo simple de la historia térmica de la Tierra.
Área de la Ciencia:
- La geofísica
- Ciencias planetarias
- El paleomagnetismo
Sus antecedentes:
- El núcleo interno de la Tierra crece a través de la solidificación del hierro líquido.
- Las estimaciones para el momento de la nucleación del núcleo interno varían ampliamente (hace 0.5 a 2 mil millones de años) debido a los diferentes valores de conductividad térmica.
- La nucleación del núcleo interno tiene un impacto significativo en la evolución térmica planetaria y el geodinamo.
Objetivo del estudio:
- Para refinar el tiempo de la nucleación del núcleo interno de la Tierra.
- Para investigar las variaciones a largo plazo en la intensidad del campo geomagnético.
- Proporcionar evidencia que apoye modelos específicos de la evolución térmica de la Tierra.
Principales métodos:
- Análisis de una base de datos ampliada de intensidad paleomagnética del Precámbrico.
- Aplicación de nuevos criterios de fiabilidad para la selección de datos paleomagnéticos.
- Examen de la intensidad y la variabilidad del campo geomagnético en escalas de tiempo geológicas.
Principales resultados:
- El estudio proporciona apoyo basado en la intensidad para la dipolaridad del campo precámbrico.
- Se encontraron pruebas firmes de variaciones a largo plazo en la fuerza geomagnética.
- Un aumento significativo en la fuerza y variabilidad promedio del campo ocurrió entre hace 1 y 1.5 mil millones de años.
Conclusiones:
- La transición observada en la intensidad del campo geomagnético sugiere fuertemente que la nucleación interna ocurrió entre hace 1 y 1.5 mil millones de años.
- Esta sincronización admite un valor de conductividad térmica del núcleo modesto.
- Los hallazgos son consistentes con un modelo simple de evolución térmica para la Tierra.
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