Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 12. 1985. (Budapest, 1985)
• 1 A2 o3 «4 X5 Fig. 3 TAS-diagram (IUGS, 1984) for basaltic and basaltic andesitic rocks of Transylvania and Bánát. Symbols same as in Fig. 2 formed (EMBEY-ISZTIN & SCHARBERT, unpublished). The basalts of Pauliberg (Pálhegy ) show a wide range of composition from the least undersaturated olivine tholeiite to the basanite (Fig. 5). Those rocks close to the olivine basaltic composition represent rather primitive liquids (with high S.I. and very low D.I. values, mg-value: 62.2-65.2, normative olivine up to 14 %). Consequently, a large amount of partial melting at shallower levels of the upper mantle and a subsequent moderate olivine! clinopyroxene fractionation should be considered. The basalts of Oberpullendorf ( Felsopulya) and Stoob (Csáva ) are mostly tholeiltes (mg-value: 60.6-61.3, normative olivine: up to 8.93 %). Clinopyroxene and olivine fractionation was apparently more intensive in this case. Basalts of Little Hungarian Plain (Kisalföld) Several isolated volcanoes composed of basaltic lavas and/or basaltic tuffs are known here. Some recent chemical analyses (EMBEY-ISZTIN & SCHARBERT, unpublished) and K/Ar age determinations (JÁMBOR & al. 1980; BALOGH 1984) are available. Old analyses published by M AURITZ (1948) were also used by the authors. The Sághegy basalt (6.27Í0.58 m.y., BALOGH 1984) is a slightly nepheline normative alkali olivine basalt, olivine basalt or olivine tholeiite (low in normative hypersthene). The normative olivine content and the mg-value are rather high, up to 14 % and 65.3 respectively. These figures indicate that the conditions of formation of Sághegy basalt were very similar to those of Pauliberg. The olivine basalt of Somló (2.98Í 0.19 m.y. .BALOGH 1984), show also similar petrochemical features to the basalt of Sághegy, however they are clearly more differentiated (D.I. between 4348; S.I. is 29-35; mg-value: 56.3-61.0 and normative olivine 8-14 %). The analyses performed on the samples originating from the drilling of Doba (near Somló) show alkali olivine basaltic affinités.
