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Arai, S., 1992: Chemistry of chrome spinel in volcanic rocks as a potential guide to magma chemistry. - Mineralogical Magazine, 56, pp. 173-184. Chemistry of chrome spinel in volcanic rocks as a potential guide to magma

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Introduction Four-phase spinel peridotite xenoliths occurring in alkaline basaltic rocks provide direct information about the conditions prevailing in the shallow subcontinental and oceanic lithospheric mantles. Peridotite

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The newly discovered crustal xenoliths from Miocene andesites in the Mátra Mts (Northeast Hungary) were classified into three petrographic types. Type 1 is a garnetiferous, plagioclase-rich cumulate rock, presumed to originate from the felsic portion of the nearby Szarvaskõ-Darnó mafic igneous complex. The almandine-rich garnet has been inferred to be of granulite facies origin. Garnet - orthopyroxene geothermobarometry on the orthopyroxene - plagioclase corona structure around it indicates a later high temperature (800-950 °C) low pressure (3-4 kbar) retrogression event. Type 2 is also plagioclase-rich cumulate rock with contact metamorphic assemblage containing spinel, corundum and andalusite, which crystallized in the course of dehydration reactions of biotite and/or smectite in hornblende hornfels to sanidinite facies conditions. Type 3 is microsyenite, which contains abundant anorthoclase and minor amount of Na- and K-rich kaersutitic-barkevikitic amphibole.

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Chemistry of chromian spinel in volcanic rocks as a potential guide to magma chemistry Mineralogical Magazine 56 173 184 . S

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Ouzegane, K., S. Boumaza 1996: An example of ultrahigh-temperature metamorphism: orthopyroxene-sillimanite-garnet, sapphirine-quartz and spinel-quartz parageneses in Al-Mg granulites from in Hihaou, in Ouzzal, Hoggar. - J. Metamorph. Geol., 14, pp. 693

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Dick, H., B., T. Bullen 1984: Chromian spinel as a petrogenetic indicator in abyssal and alpine-type peridotites and spatially associated lavas. - Contrib. Mineral. Petrol., 86, pp. 54 - 76 . Chromian spinel as a petrogenetic

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In Central Europe, Early Cretaceous alkaline igneous rocks (lamprophyres, basanites, phonolites) occur in the Moravian-Silesian Beskidy area (northern Czech Republic and southern Poland) and in the Mecsek-Alföld Zone (southern Hungary). Presently they are located at about 400 km distance of each other. These alkaline igneous rocks show close similarities in their mineral, chemical, and bulk rock compositional data, implying similar petrogenesis and suggesting that these two regions could have been much closer during the Early Cretaceous; they could belong to the same rift zone in the European continental margin. Their trace element distribution and Sr and Nd isotopic ratios suggest that the parental magmas derived from an enriched, HIMU OIB-like asthenospheric mantle by different degrees (3-6%) of partial melting at the depth of spinel-garnet transitional and garnet stabilization zone (about 60-80 km depth). This mantle source appears to be akin to that thought to have supplied the Tertiary to Quaternary alkaline mafic magmas in Europe (EAR=European Asthenospheric Reservoir). This may imply that this EAR-type mantle reservoir could have been present beneath Europe at least since the Early Cretaceous. It could reside at the base of the upper mantle (670 km discontinuity) supplying upwelling hot mantle fingers, or it may represent a long-lasting, polluted (HIMU+depleted MORB mantle) upper mantle at shallow depth beneath Europe.

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.A. Binns 1970 (Mg,Fe)2SiO4 Spinel in a Meteorite Physics of Earth and Planetary Interiors 3 156 160

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Jurković, I., M. Jaksic 1994: A zincian-chrome-spinel from the Cr-Ba-Fe-Cu deposits near Busovaca (Bosnia and Hercegovina). - Geol. Croatica, 47, pp. 83 - 102, Zagreb. A zincian-chrome-spinel from the Cr-Ba-Fe-Cu deposits near

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. 155 423 429 Árgyelán, G., G. Császár 1998: Detrital chrome spinels in Jurassic formations of the Gerecse Mountains, Hungary. -- Földt. Közl., 128

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