Klébesz, Rita

Kovács, István

Liptai, Nóra

Patkó, Levente

Pintér, Zsanett

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II6hLHERZOLITEfrom 4 to 15 may 2014OROGENIC LHERZOLITE CONFERENCEMarrakechMOROCCOfrom 4 to 15 may 2014OROGENIC LHERZOLITE CONFERENCEMarrakechMOROCCO_ ~J:l!-~onference field trip to -.!he Beni Bousera Q!'~genic P~ridotite ,_____ _ _ _.__- Conference ~eeting i~ Mar~kec~ lH6tel Le Semi_r_am_~_'s_) ___ ~-conf~~~e_field_ trip to the Middle Atlas Volcanics and Mantle Xe_n_o_l_i_th_s __________ ~~ Post-conference fie~ trip to the Anti-Atlas Pan-African OphioitesUnderstanding the complex physico-chemical features of the uppermantle beneath the N ognid-Gomor Volcanic Field (N orthernPannonian Basin) - A study on peridotite xenolithsN6ra Liptai!, Levente Patk61, Istvan Kovacs2, Zsanett Pinter3, Rita Klebesz4, Lasz16 E. Aradjl,Csaba Szab6!(1) Lithosphere Fluid Research Lab, Institute of Geography and Earth Sciences, Eotvos University,Budapest, Hungary(2) Geological and Geophysical Institute of Hungary, Budapest, Hungary(3) Bayerisches Geoinstitut, University of Bayreuth, Bayreuth, Germany(4) MT A CSFK Geodetic and Geophysical Instiute, Sopron, HungaryThe N6grad-Gomor Volcanic Field (NGVF) is located in the northern part of the PannonianBasin, and is one of the five occurrences in the Carpathian-Pannonian region where xenolithsfrom the upper mantle and lower crust were enclosed and brought to the surface by Plio-Pleistocene alkali basalts. Upper mantle peridotite xenoliths of the NGVF can be divided intotwo lithologically different suites: lherzolites, which represent the depleted lithospheric mantle,and wehrlites, which were formed from lherzolites by cryptic and stealth metasomatism duringmelt-rock interaction. This study focuses on the petrography and geochemistry of the lherzolitesuite because recent studies proved that these xenoliths are geochemically diverse and havesuffered cryptic metasomatism to various extents.Out of more than 200 collected samples, 15 representative lherzolite xenoliths were selectedfrom the central and southern part of the NGVF for detailed petrographic study, analyses ofmajor and trace element contents and measurements of crystal preferred orientation (CPO).Major element geochemistry revealed that composition of most of the lherzolite xenoliths matchthat of the average, depleted lithospheric mantle with approximately 20 % partial melting;however, some of the samples exhibit characteristically lower Mg-numbers, indicatingmetasomatic effect resulting in Fe enrichment. This suggests reaction with a melt whosecomposition is different from the host magma, and which could be the metasomatic agent thatcreated the wehrlite bodies by alteration of the lherzolites. This assumption is supported furtherby trace element analyses that show various amounts of LREE enrichment, proposing thatmetasomatism has affected parts of the upper mantle to different degrees.CPOs of olivine show a difference in fabric strength between lherzolite xenoliths from thecentral and the southern part of the NGVF, which may be attributed either to the difference in thedepth of origin or the vicinity of major structural lines in case of the central part. Samples fromthe central part of the volcanic field represent a deeper domain of the lithospheric mantle thanthe ones from the southern part, and therefore may have been affected by a different deformationmechanism. Based on the results, we concluded that the xenoliths were not only subject tometasomatic processes, but also went through various deformation episodes, which occurredmost probably during the Neogene evolution of the Pannonian Basin.r---------MANAGEMIRSESMEDYNA~C~V,S•• Fth~TNC~TsMAROCREpUBLlQUE FRAN(;AISEAt.UIASSAlll DJ:. FRASCl AU MAROC

Understanding the complex physico-chemical features of the upper mantle beneath the Nógrád-Gömör Volcanic Field (Northern Pannonian Basin) - A study on peridotite xenoliths

Understanding the complex physico-chemical features of the upper mantle beneath the Nógrád-Gömör Volcanic Field (Northern Pannonian Basin) - A study on peridotite xenoliths

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