THE FIRST DISCOVERY OF ALLANITE-(CE) IN THE UKRAINIAN CARPATHIANS
DOI:
https://doi.org/10.15407/dopovidi2025.06.085Keywords:
rare earth mineral, reniform aggregates, Chyvchyny suite, Marmaros massifAbstract
Rare earth silicate from the epidote supergroup was found in a metamorphosed xenolith of terrigenous-carbonate rock among the spilitized Mesozoic (J3-K1) effusives of the Chyvchyny suite in the Marmaros massif of the Carpathians. The content of Co and REE in the effusives is several times higher than that of Clark. U, Th and Y were not found. According to the results of microprobe analyses, the mineral was identified as allanite-(Ce). This is the first discovery of allanite in the Ukrainian Carpathians and the second discovery of a rare-earth mineral (after monazite) in this region. Individuals of the mineral with a size of 10–20 μm, together with chalcedony, titanite magnetite, chlorite and calcite, form kidney-shaped aggregates up to 100 μm in size. Allanite is brownish-brown in color, weakly anisotropic. Crystal chemical formula: Ca1.48REE0.46Al2.26Fe0.74Si3.07O12(OH) indicates significant substitution of REE positions by calcium. The mineral was formed as a result of the interaction of REE-enriched basaltic lava with limestone rocks.
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