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Registration Number

0221U101815, 0116U002908 , R & D reports

Title

Geochemistry of rare-earth elements in accessory and rock-forming minerals of granitoids of the Ukrainian shield

Head

Vovk Katerina V., Кандидат геологічних наук

Registration Date

25-01-2021

Organization

M. P. Semenenko Institute of geochemistry, mineralogy and ore formation

Description

The object of the study were rocks and minerals of the Ukrainian Shield, standard samples of rocks. The purpose of the work is to determine the content and distribution of rare earth elements in the granitoids of the western and central part of the Ukrainian Shield; development of an effective method of sample preparation of granites and minerals in a microwave field. Optimal physicochemical conditions of decomposition and dissolution of rocks and minerals using microwave radiation have been established. The optimal composition and concentration of solvents are determined. The distribution of rare earth elements in rocks and minerals of the Dniester-Bug, Rosyn-Tikyts and Ingul megablocks has been studied. The distribution of REE in apatites from xenoliths of metamorphic rocks of Bereznin and Tyvriv strata (Dniester-Bug megablock) was studied. The gradual change of the total amount of REE from the central parts of xenoliths to the contacts zones and in the granitoids was revealed. Based on these studies, it was concluded that the xenoliths of metamorphic rocks of the Bereznin stratum is a substrate for granitoids of the Berdychiv complex, and the xenoliths of metamorphic rocks of the Tyvriv strata is is a dyke formation. A significant part of REE in the studied dioritoids of the Gaisin block of the Rosyn-Tikyts megablock is concentrated in accessory minerals, first of all in monazite, xenotime, apatite. In the latter, REE is concentrated in monazite inclusions, which are considered to be the result of solid solution decomposition. One of the main accessory minerals-concentrators of REE in the granitoids of the Ruska-Polyana massif of the Ingul megablock of the US is fluorite. Its role as a concentrator of lanthanides is growing in the most differentiated gray-pink fine-medium-grained granites. It was found that the high level of REE in fluorites from these granites is associated with small needle inclusions of bastnesite.

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Zaiats Olga V
Lisna Iryna M
Proskurko Lyubov I
Samchuk Anatoliy I
Shvaika Igor D
Shvaika Iryna A