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El azufre atmosférico en los depósitos de níquel alojados en komatiitas del Arqueo
Andrey Bekker1, Mark E Barley, Marco L Fiorentini
1Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, USA. bekker@cc.umanitoba.ca
Science (New York, N.Y.)
|December 8, 2009
Resumen
El azufre en los depósitos de sulfuro de hierro-níquel del Arqueo se originó a partir del procesamiento atmosférico y la acumulación en el fondo del océano. Los magmas derivados del manto incorporaron este azufre, formando depósitos cuando los océanos eran pobres en azufre.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Geología económica Geología económica.
- Paleobiología precámbrica Paleobiología precámbrica.
Sus antecedentes:
- Grandes depósitos de mineral de sulfuro de hierro-níquel (Fe-Ni) se formaron durante las eras Arcaico y Proterozoico temprano.
- Comprender la fuente de los metales y el azufre es clave para su formación.
- Los océanos arcaicos se caracterizaban por bajas concentraciones de azufre.
Objetivo del estudio:
- Para investigar el origen del azufre en los depósitos de sulfuro de Fe-Ni alojados en comatiites arcaicas.
- Para dilucidar los procesos involucrados en la génesis de estos importantes cuerpos de mineral.
Principales métodos:
- Análisis de los datos de isótopos múltiples de azufre de los depósitos de sulfuro de Fe-Ni alojados en komatiitas arcaicas.
- Reconstrucción de las vías de ciclo del azufre desde el ambiente atmosférico al oceánico.
Principales resultados:
- Los datos de isótopos de azufre sugieren un procesamiento atmosférico previo y una posterior acumulación en el fondo del océano.
- La evidencia indica que el azufre se obtuvo del sulfuro hidrotermal del fondo marino y de las pizarras sulfúricas.
- Los magmas komatiíticos derivados del manto asimilaron este azufre procesado.
Conclusiones:
- El azufre en los depósitos de sulfuro de Fe-Ni de Archean se originó en depósitos atmosféricos y oceánicos.
- Los magmas de Komatiite jugaron un papel crucial en la incorporación de este azufre para formar depósitos de mineral.
- Este estudio arroja luz sobre los procesos de formación de mineral en los primeros océanos de la Tierra limitados en azufre.
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