Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 99. (Budapest 2007)

Embey-Isztin, A. ; Dobosi, G.: Composition of olivines in the young alkali basalts and their peridotite xenoliths from the Pannonian Basin

From such primitive melts olivines with Fog7_88 could have precipitated. We have measured however, an outstandingly large number of olivine phenocrysts in moderately differentiated lavas showing similarly high Fo (Fig. 9). This may indicate that in the Pannonian Basin the primary magmas of most, or if not all of the volcanoes, had a Mg-value of 67-68. Phenocrysts with Fo higher than 87-88 seem to have originated as xenocrysts, whereas more iron-rich olivine phenocrysts attest to a re-equilibration process. Acknowledgements - Our work has been supported by the Hungarian Scientific Research Fund (OTKA grant Nos T-37382 and T-49176). REFERENCES DIETRICH, H. & POULTIDIS, H. 1985: Petrology of ultramafic xenoliths in alkali basalts from Klöch and Stradner Kogel (Styria, Austria). - Neues fahrbuch fur Mineralogie Abhandlungen 151: 131-140. DOBOSI, G. 1989: Clinopyroxene zoning patterns in the young alkaline basalts of Hungary and their petrogenetic significance. - Contributions to Mineralogy and Petrology 101: 112-121. DOBOSI, G. 2003: A felsőköpeny és az alsókéreg geokémiája a bázisos vulkánitok és xenolitjainak vizsgálata alapján - elsősorban a Kárpátmedence példáján. [Geochemistry of the upper mantle and lower crust on the basis of investigations of basic volcanic rocks and their xenoliths - mainly in the Carpathian Basin.] - MTA doktori értekezés. [DSc Thesis.] 294pp. [Manuscript deposited in the Library of the Hungarian Academy of Sciences, Budapest.] DOBOSI, G., SCHULTZ-GÜTLER, R., KURAT, G. & KRACHER, A. 1991: Pyroxene chemistry and evolution of alkali basaltic rocks from Burgenland and Styria, Austria. - Mineralogy and Petrology 43: 275-292. DOBOSI, G., FODOR, R. V. & GOLDBERG, S. A. 1995: Late-Cenozoic alkalic basalt magmatism in the northern Pannonian Basin, eastern Europe: petrology, source compositions, and relationship to tectonics. - Acta Volcanologica 7: 199-207. DOBOSI, G., KURAT, G., JENNER, G. A. & BRANDSTÄTTER, F. 1999: Cryptic metasomatism in the upper mantle beneath Southeastern Austria: a laser ablation microprobe-ICP-MS study. - Mineralogy and Petrology 67:143-161. DOWNES, H., EMBEY-ISZTIN, A. & THIRL WALL, M.F.I 992: Petrology and geochemistry of spinel peridotite xenoliths from the western Pannonian Basin (Hungary): evidence for an association between enrichment and texture in the upper mantle. - Contributions to Mineralogy and Petrology 109: 340-354.