Laboratorio de Geocronología en el Servicio Geológico Colombiano: avances sobre datación U-Pb en circones mediante la técnica LA-ICP-MS
DOI:
https://doi.org/10.32685/0120-1425/boletingeo.44.2018.7Palabras clave:
Ablación, láser, espectrometría de masas, datación, geocronología, U/Pb, circones, LA-ICP-MS.
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En este trabajo se presentan los primeros resultados de la implementación del Laboratorio de Datación U-Pb en el Servicio Geológico Colombiano con la técnica analítica LA-ICP-MS para datación U-Pb. Este método geocronológico está basado en el decaimiento radiactivo de los isótopos de Uranio (238U/206Pb y 235U/207Pb), con el fin de ser empleado en la determinación de edades en circones. Como parte del proceso, se trabajó en la evaluación de materiales de referencia con diferentes rangos de edades, utilizando parámetros analíticos similares a los que utilizan otros laboratorios de diversas partes del mundo, con el fin de obtener resultados de precisión y exactitud óptima para esta técnica analítica. Los resultados obtenidos muestran que, en general, para la mayoría de los materiales de referencia, la precisión como coeficiente de variación y veracidad, como la diferencia entre la edad esperada y la obtenida, es menor del 2 %. Además, se evaluó la concordancia del sistema U-Pb mediante diagramas de concordia, y se encontró que la desviación de la media estándar ponderada (MSWD), en la mayoría de los estándares, es menor de 2, lo cual implica que se obtuvieron resultados en el margen de los parámetros estadísticos establecidos.
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