Minor-element and revised major-element contents of some Mediterranean pantellerites and comendites

Optical emission spectrographic analysis of three pantellerites from Pantelleria and two comendites from Sardinia show high concentrations of B, Be, Ga, La, Mo, Nb, Sn, Y, Yb, and Zt and low contents of Ba, Co, Cr, Ni, Sr, and V. Minor-element trends of these specimens are very similar to those of pantellerites from southern Nevada and New Zealand and other peralkaline silicic rocks from various localities. Fluorine contents of the Pantellerian specimens range from 0.19 to 0.32 per cent by weight resulting in 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-phase compositions for the three Pantellerian specimens are given.