Gallium, tin, lead, Germanium, bismuth and silver in the Fe-enriched and al-enriched rocks on the Maldynyrd range (Polar Ural)

Special emission spectrographycal method was developed for the determination of volatile trace elements in Fe-rich and Al-rich shales from the Maldynyrd Ridge, the Polar Urals. 207 rock samples (71 Fe-rich and 136 Al-rich) were analysed for Ga, Sn, Pb, Ge, Bi and Ag. Most Fe-rich samples have near-Clarke contents of trace elements, but some geochemical anomalies were found. Average contents of Ga, Sn and Pb are 34, 19 and 16 ppm. Al-rich shales (contained pyrophyllite and diaspore) are enriched in Ga and Sn; average contents are 56 and 21 ppm. The contents of Ga and Sn correlate with Al2O3 content. The enrichment of volatile trace elements in Al-rich aporhyolitic shales was to be connected with måtasomatic (greizen - type) alteration of rhyolites.