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Desproporción de azufre microbiano activo en el Mesoproterozoico
David T Johnston1, Boswell A Wing, James Farquhar
1Department of Geology and Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742, USA. dtj@geol.umd.edu
Science (New York, N.Y.)
|December 3, 2005
Resumen
La desproporción de los compuestos de azufre estaba activa hace 1300 millones de años, antes de lo que se pensaba. Los nuevos datos de isótopos de azufre sugieren que la Tierra es la Tierra.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Paleoclimatología Paleoclimatología
- Geoquímica de isótopos La geoquímica de isótopos es la química de los isótopos.
Sus antecedentes:
- Estudios previos vincularon la desproporción de los compuestos de azufre con el oxígeno atmosférico aumenta entre 640 y 1050 millones de años atrás (Ma).
- Estos vínculos se basaron en cambios en las fraccionamientos isotópicos de azufre-34 sobre azufre-32 (34S/32S) entre sulfato y sulfuro.
Objetivo del estudio:
- Para presentar un registro de isótopos de sulfato de agua de mar del Proterozoico que incorpora el isótopo de azufre-33 (33S).
- Para refinar la línea de tiempo para la desproporción de los compuestos de azufre y su relación con la oxigenación temprana de la Tierra.
Principales métodos:
- Análisis del sulfato de agua de mar del Proterozoico utilizando relaciones de isótopos de azufre, incluyendo 34S/32S y 33S/32S.
- Reconstrucción del ciclo del azufre basado en patrones de fraccionamiento isotópico.
Principales resultados:
- La desproporción de los compuestos de azufre estaba activa en el ciclo del azufre desde hace 1300 millones de años.
- La inclusión de datos 33S proporciona un registro más robusto del ciclo del azufre.
Conclusiones:
- La Era Mesoproterozoica probablemente vio una progresiva oxigenación de la superficie de la Tierra.
- El momento de la desproporción de los compuestos de azufre es más temprano de lo que se había establecido anteriormente, lo que afecta a los modelos de los primeros entornos de la Tierra.
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