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El nacimiento de la tectosfera de Kaapvaal hace 3.08 mil millones de años
D E Moser1, R M Flowers, R J Hart
1Geology and Geophysics Department, University of Utah, 135S 1460E, Salt Lake City, UT 84112-0111, USA. demoser@mines.utah.edu
Science (New York, N.Y.)
|February 13, 2001
Resumen
El estudio data con precisión el nacimiento de la tectosfera, el antiguo escudo continental de la Tierra, hace 3.08 mil millones de años. Este hallazgo ayuda a entender cómo se formaron y estabilizaron los continentes al principio de la historia de la Tierra.
Área de la Ciencia:
- Geología Geología Geología.
- Geocronología Geocronología.
- La tectónica es la tectónica.
Sus antecedentes:
- Los continentes arcaicos están protegidos por las profundas raíces de la litosfera del manto.
- El momento de este acoplamiento entre la corteza y el manto (nacimiento de la tectosfera) es crucial para comprender las teorías de génesis de las placas continentales.
Objetivo del estudio:
- Para determinar el momento preciso del nacimiento de la tectosfera en el cratón Kaapvaal.
- Para investigar los procesos y la escala de tiempo del crecimiento de la raíz del manto.
Principales métodos:
- Cartografía geológica de una sección generada por el impacto a través de la corteza mesoarqueana.
- Geocronología de alta precisión para fechar eventos geológicos.
Principales resultados:
- El nacimiento de la tectosfera ocurrió hace 3.08 ± 0.01 mil millones de años.
- Esto fue aproximadamente 0.12 mil millones de años después del ensamblaje de la corteza.
- La raíz del manto del sur de África creció a través de la subducción en aproximadamente 0.2 mil millones de años.
Conclusiones:
- El ensamblaje de la corteza anterior a la formación de la raíz del manto puede ser una característica común del desarrollo de la tectosfera.
- Proporciona datos críticos para los modelos de la evolución continental de la Tierra temprana.
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