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. leading place in geological structure occupied by rock association, which includes number plutonic formations from gabbro to leucocratic granites (gabbro-diorite-granodiorite-granite association), formed Paleoproterozoic — 1,98—1,95 Ga. results lead-lead isotope dating titanites diorites, opened RPZ-5 quarry, located northwestern vicinity village Tomashhorod. Diorites were second phase, after gabroids, before beginning formation granitoids. age 1975 ± 9,1 Ma was obtained for them. calculated based on previously published data 1973 8,3 Ma, good agreement with U-Pb isotopic zircons these diorites 1974 1,2 Ma. It found that determine high content ordinary lead, it enough use only composition calculating coordinates graph 207Pb/204Pb 206Pb/204Pb, tangent angle inclination regression line.