Aradi, László Előd

Liptai, Nóra

Patkó, Levente

English

Liptai Nóra

Patkó Levente

Aradi László Előd

University of Szeged

Acta Mineralogica-Petrographica, Abstract Series, Szeged, Vol. 7, 2012 79 Joint 5th Mineral Sciences in the Carpathians Conference and 3rd Central-European Mineralogical Conference 20–21 April, 2012, University of Miskolc, Miskolc, Hungary MODAL COMPOSITIONS AND TEXTURES OF ALKALI BASALT HOSTED UPPER MANTLE XENOLITHS FROM THE NORTHERN PART OF THE CARPATHIAN-PANNONIAN REGION (NÓGRÁD-GÖMÖR VOLCANIC FIELD, HUNGARY-SLOVAKIA)  LIPTAI, N.Lithosphere Fluid Research Lab, Department of Petrology and Geochemistry, Eötvös University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary *, PATKÓ, L. & ARADI, L.  * E-mail: n.liptai.elte@gmail.com  One possible way to understand upper mantle proc-esses better is to study ultramafic xenoliths hosted in alkali basalt, kimberlite and lamprophyre. Upper mantle xenoliths from the five volcanic fields of Plio-Pleistocene alkali basalts in the Carpathian-Pannonian region (Styrian Basin, Little Hungarian Plain, Bakony-Balaton Highland, Nógrád-Gömör Volcanic Field, Per-şani Mountains) have provided matter to petrologic and geochemical studies in the last few decades (e.g. EM-BEY-ISZTIN et al., 1989, 2001; DOWNES et al., 1992; SZABÓ, 2004; DOBOSI et al., 2010). In our work we concentrate on the Nógrád-Gömör Volcanic Field (NGVF), located at the northern part of the Carpathian-Pannonian region. We collected xenoliths from the central part of the area, including five quarries from Medves Plateau and Babi Hill that have barely been studied before. From more than 200 collected xenoliths, over 80 samples were chosen for detailed petrographic examina-tions. The main aim was to determine texture types and modal compositions of the xenoliths regarding the rock-forming minerals, as well as describe fabrics of the mantle constituents (olivine, orthopyroxene, clinopy-roxene and spinel). Based on the results, we present a detailed summary about the NGVF xenoliths, showing how they can be correlated with xenoliths originating from better researched marginal areas, introducing a texture type (poikilitic) (Fig. 1), as well as a rock type (wehrlite) (Fig. 2) that have not been reported before in earlier studies on the central part of the NGVF. It will also be presented that wehrlites show features of differ-ent texture types in the form of clinopyroxene-spinel aggregations sitting in the original texture, which indi-cates a possible mantle metasomatism that took place before the ascension of the host basaltic melt. Presence of amphibole in some of the xenoliths also confirms that this process enriched the upper mantle in incompatible elements.  References DOBOSI, G., JENNER, G.A., EMBEY-ISZTIN, A. & DOWNES, H. (2010): Geological Society, London, Special Publications, 337: 177–194. DOWNES, H., EMBEY-ISZTIN, A. & THIRLWALL, M.F. (1992): Contributions to Mineralogy and Pe-trology, 109: 340–354. EMBEY-ISZTIN, A., SCHARBERT, H.G., DIET-RICH, H. & POULTIDIS, H. (1989): Journal of Pe-trology, 30: 79–105. EMBEY-ISZTIN, A., DOBOSI, G., ALTHERR, R. & MEYER, H.P. (2001): Tectonophysics, 331: 285–306. SZABÓ, Cs., FALUS, Gy., ZAJACZ, Z., KOVÁCS, I. & BALI, E. (2004): Tectonophysics, 393: 119–137.      Fig. 1. Olivine (ol) inclusion in orthopyroxene (opx) as an indication of poikilitic textured lherzolite;  transmitted light, N+  Fig. 2. Aggregation of clinopyroxene (cpx) and  vermicular spinel (sp) in a wehrlite; transmitted light, 1N 

Modal compositions and textures of alkali basalt hosted upper mantle xenoliths from the Northern part of the Carpathian-Pannonian region (Nógrád-Gömör volcanic field, Hungary-Slovakia)

http://acta.bibl.u-szeged.hu/33014/1/mineralogica_as_007_079.pdf

Modal compositions and textures of alkali basalt hosted upper mantle xenoliths from the Northern part of the Carpathian-Pannonian region (Nógrád-Gömör volcanic field, Hungary-Slovakia)

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