Minor-element and Revised Major-element Contents of Some Mediterranean Pantellerites and Comendites

Optical emission spectrographic analysis of three pantelleritesfrom Pantelleria and two comendites from Sardinia show highconcentrations of B, Be, Ga, La, Mo, Nb, Sn, Y, Yb, and Zt andlow contents of Ba, Co, Cr, Ni, Sr, and V. Minor-element trendsof these specimens are very similar to those of pantelleritesfrom southern Nevada and New Zealand and other peralkaline silicicrocks from various localities. Fluorine contents of the Pantellerianspecimens range from 0.19 to 0.32 per cent by weight resultingin abnormally high Cl to F ratios. New analyses for MgO, Na₂O,and K₂O are almost identical with the values obtained by Zies.Revised major-element compositions and calculated glass-phasecompositions for the three Pantellerian specimens are given.