Features of REE Distribution in Apatites of Granulite-Gneiss Rocks of Podilsk Block Ukrainian Shield

Abstract

FEATURES OF REE DISTRIBUTIOn In APATITES OF GRAnULITE-GnEISS ROCKS OF PODILSK BLOCK UKRAInIAn SHIELDAs a result of studying of the distribution of rare earth elements (REE) in apatites from metamorphic rocks that occurr as xenoliths (skialites) among Berdychiv granites and charnockites of the Podilsk block of the Dniester-Bug Megablock of the Ukrainian Shield, it was found that apatites of granulite-gneiss rocks are characterized by a low fractionation of REE with predominant light REE and sharp deficiency europium, which is characteristic of calc-alkaline rocks of other shields. As to the metamorphic rocks of the Bereznin stratum the maximum content of REE found in apatites is characteristic of melanocratic rocks which commonly found in the central zones of metamorphic xenoliths. At the contact with granitoids the content of REE decreases. All xenoliths became zonal due to the such factor as acid-basic ratio that control the differentiation of REE in mineral-forming environment. It has been suggested that the spectra of REE distribution found in apatites from metamorphic rocks, which occur as of xenoliths among granitoids, may indicate the nature of xenoliths. They can be either the substrate for these granitoids or occur as dyke or restite formations.