Determination of beryllium and its distribution in rocks of the SnW granite of Regoufe, northern Portugal

Abstract

The determination of Be by electrothermal atomic absorption spectrometry with Zeeman background correction (ZETAAS) is compared with the determination by inductively coupled plasma emission spectrometry (ICPES). The samples are decomposed with a HFHCIO 4HNO 3 method. Both methods compare well though the results by ZETAAS are generally ∼ 2 ppm higher than the ICPES values. Especially ICPES results are in good agreement with the accepted values for international reference samples. ZETAAS has a lower detection limit than ICPES. The methods were tested on 55 samples of the Regoufe granite, northern Portugal. The average for the Regoufe granite is 17 ppm Be, and the values range from 4 to 57 ppm Be. The granite may be regarded as Be-specialised. The distribution is compared with those of the elements Ti, P, Rb, Sr, Cu, Zn, U, Sn, W, Ta, Nb, F, Li and Cs, and with major minerals in the granite (feldspars and micas). Correlations with Be were generally low. From theoretical considerations and from statistical data it is concluded that Be is enriched in the final stages of the magma crystallisation and was mobile in all the major late- and post-magmatic processes in the granite.