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  • Author or Editor: Piero Manetti x
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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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