MINERAL COMPOSITION OF RARE ELEMENT ENRICHED ROCK BODIES FROM THE BÜKK MTS., NE HUNGARY
DOI:
https://doi.org/10.33030/geosciences.2022.15.022Keywords:
rare earth elements, High Field Strength Elements, metasomatism, alteration processes, phyllosilicates, feldspars, Bükk Mts.Abstract
A rare earth (REE) and further rare element (Zr, Nb, Th, Ta) enrichment was found recently within the CriticEl project in 2016. Due to continuing studies, now we know about several enriched rock bodies from the SE and NE part of the Bükk Mts. The enrichment was caused by metasomatic processes, during which fluids penetrated through the rock bodies, causing chemical and mineralogical changes. The enriched rock bodies are Triassic metavolcanics and siliciclastic metasedimentary rocks. The protoliths consist of quartz, feldspars (albite and potassic feldspars), phyllosilicates (various micas and chlorites) and calcite, and in minor quantities Fe- and Ti-oxides, fluorapatite and titanite. The characteristic metasomatic minerals are monazite-(Ce), zircon and Nb-bearing Tioxide. Based on our data, micas and potassic feldspars were generated at least partly during the rare element mineralization process, while titanite, chlorite and albite were consumed. Apatite and Ti-oxides were decomposed and formed. The original mineral composition had a strong influence on the rate and mode of alteration.
