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Una dinamo del núcleo lunar de larga duración
Erin K Shea1, Benjamin P Weiss, William S Cassata
1Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Science (New York, N.Y.)
|January 28, 2012
Resumen
Una dínamo del núcleo lunar probablemente existió hace 4.200 millones de años. Un nuevo análisis de una muestra lunar de hace 3.700 millones de años extiende la dínamo.
Área de la Ciencia:
- Geología y geofísica lunares.
- El paleomagnetismo es el paleomagnetismo.
- Ciencias planetarias Ciencias planetarias.
Sus antecedentes:
- La existencia y la duración de la dinamo del núcleo de la Luna no se comprenden completamente.
- Estudios previos sugieren que una dínamo lunar existió hace 4.200 millones de años, pero su historia posterior sigue sin estar clara.
Objetivo del estudio:
- Para investigar la longevidad e intensidad de la dinamo del núcleo lunar.
- Para analizar una muestra de basalto de marea lunar de 3.700 millones de años de antigüedad en busca de evidencia paleomagnética.
Principales métodos:
- Medidas paleomagnéticas en una muestra lunar 10020.
- Análisis petrológico.
- (40) Ar/(39) Ar es la térmocronometría.
Principales resultados:
- La muestra de 3.700 millones de años de antigüedad 10020 exhibe una magnetización de alta coercitividad.
- La magnetización indica la adquisición en un paleocampo lunar estable de al menos 12 microteslas.
- Esta evidencia extiende la vida útil conocida de la dínamo lunar en 500 millones de años.
Conclusiones:
- La dinamo lunar persistió durante al menos 3.700 millones de años.
- Una dinamo lunar de larga vida probablemente requirió una fuente de energía más allá de la simple refrigeración interna.
- La fuerte intensidad inferida del paleocampo desafía las teorías de dinamo existentes.
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