O.B. Vysotsky, U-Pb age of titanite from diorit of Osnytsky Block (Volyn Megablock of Ukrainian Shield)

https://doi.org/10.15407/gpimo2023.01.079

O.B. Vysotsky, PhD (Geol.), Research Fellow
e-mail: alek.vysotsky@gmail.com ORCID 0000-0002-3542-4685

L.M. Stepanyuk, NAS Corresp. Member, Dr. Sci. (Geol.), Prof., Deputy Director
e-mail: stepaniuk@nas.gov.ua ORCID 0000-0001-5591-5169

Т.І. Dovbush, Research Fellow
e-mail: tetyana.dovbush1@gmail.com ORCID 0000-0002-3512-3313

О.V. Ziultsle, PhD (Geol.), Research Fellow
e-mail: olegzjults@gmail.com ORCID 0000-0002-6204-2009

M.P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation of the NAS of Ukraine
34, Acad. Palladin Ave., Kyiv, Ukraine, 03142

U-Pb AGE OF TITANITE FROM DIORIT OF OSNYTSKY BLOCK (VOLYN MEGABLOCK OF UKRAINIAN SHIELD)

The Osnytsky block is a constituent part of the Osnytsky-Mikashevytsky volcano-plutonic belt. The leading place in the geological structure of the Osnytsky block is occupied by the rock association, which includes a number of plutonic formations from gabbro to leucocratic granites (gabbro-diorite-granodiorite-granite association), formed in the Paleoproterozoic — 1,98—1,95 Ga.

The results of lead-lead isotope dating of titanites from diorites, opened by the RPZ-5 quarry, located in the northwestern vicinity of the village Tomashhorod. Diorites were formed in the second phase, after gabroids, before the beginning of the formation of granitoids. The age of 1975 ± 9,1 Ma was obtained for them. The age calculated based on previously published data is 1973 ± 8,3 Ma, which is in good agreement with the U-Pb isotopic age of the zircons of these diorites 1974 ± 1,2 Ma. It was found that to determine the isotopic age of titanites with a high content of ordinary lead, it is enough to use only the isotopic composition of lead, calculating the age in the coordinates of the graph 207Pb/204Pb — 206Pb/204Pb, by the tangent of the angle of inclination of the regression line.

Keywords: U-Pb isotopic age, diorite, titanite, Osnytsky block.

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