Stepanyuk L.M., Syomka V.O., Karly Z.V., Bondarenko S.M., Dovbush T.Y., Kurylo S.Y.
M.P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation of the National Academy of Sciences of Ukraine
Language: Ukrainian
Geochemistry and ore formation 2015, 35: 3-10
https://doi.org/10.15407/gof.2015.35.003
Rare earth ores of the Balka Korabelnaya deposit were formed due to magnesian-ferriferous-potassium metasomatism in pegmatites and in plagiogranites enclosing them. Uranium ore formation of silica-potassium rock association is attributed to potassium metasomatism. In uranian deposits (occurrences) of this rock association, Juzhnoe, Kalinovskoe, Lozovatskoe and some others, several metasomatic alteration stages have been observed: microclinisation, biotitisation and silicification. Last one is an ending of postpegmatitic hydrothermal mineral formation; during this stage sulfides and uranium minerals were deposited. A feature of the deposit is that the primary metasomatic microclinisation was ended with magnesian-ferriferouspotassium metasomatism. Main mineral of such a process is biotite. The ore mineral stage is characterized by the mineral association consisted of biotite, rare earth minerals, apatite, zircon, magnetite and titanomagnetite, which were deposited in crack zones and cataclastic ones. During the stage magnesium, iron, phosphorus, rare earth elements, thorium and uranium were supplied. In zones of the most intensive metasomatic process the micaceous rocks with a large shot of rare earth minerals were formed. Process of the ore formation was ended with a crystallization of small amounts of the uranium minerals.
Silicification, the most final hydrothermal stage which is developed in the famous uranium deposits of silica-potassium rock association, there are no tracks at this deposit. According to U-Pb age study of zircons and monazites of metasomatite (sample БК-2) on right bank of the Bolshaya Korabelnaya river and monazites of granites (sample БК-1) on left bank of the same
river, their simultaneous formation is defined. It may be indirect evidence of a genetic link between the processes of formation of kirovograd granitoid rock association and yttrium-rare earth-thorium mineralization of the Balka Korabelnaya deposit.
Key words: deposit, mineralogy, ore formation, geochronology.
References
1. Derzhavna heolohichna karta Ukrayiny. Tsentralʹnoukrayinsʹka seriya. Arkush L-36- II (Voznesensʹk). M-b 1 : 200 000. Kyiv. 2004, 112 p.
2. Kononov YU.V., Nechayev S.V. Metasomatychna mineralizatsiya v dokembriysʹkykh mihmatytakh Pobuzhzhya. Pytannya heokhimiyi, mineralohiyi i petrohrafiyi. Kyiv. Vyd-vo AN URSR, 1963, pp. 289-301.
3. Krough T.E. A law contamination method for hedrotermal decomposition of zircon and extraction of U and Pb for isotopic age determination. Geochim. Cosmochim. Acta. 1973, 37, No 3, pp. 485-494. https://doi.org/10.1016/0016-7037(73)90213-5
4. Ludwig K.R. Pb Dat for MS-DOS, version 1.06. U.S. Geol. Survey Open-File Rept. 1989, No 88. 542, p. 40.
5. Ludwig K.R. ISOPLOT for MS-DOS, version 2.0. Ibid. 1990, No 88. 557, p. 38.