Zircon and Monazite as Geochronometers

The paper discusses the results of U-Pb isotope dating monazites and zircons from granitoids formed under PT conditions granulite amphibolite facies gneisses, crystalline shales that are like xenoliths in these Ukrainian Shield. In some cases, such as Berdychiv-type Zhezhelivsky quarry, age values outer edges coincide well; others, granites Ivanivsky they differ by more than error. Odessa even greater differences were found between zircon (1.95-1.96 ± give errors Ga) mafic granulite, (1.99 monazite (1.89-1.83 a crosscutting enderbite. system vein biotite granite common this quarry does not meet Ahrens-Wetherill model. 207Pb / 206Pb ranges 1909.5 to 1867.0 5 Ma, i.e. 40 Ma. For Sabarivsky significant (2015.8-1984.8 Ma), which significantly exceed analytical error, do allow use concordia diagram interpret data obtained for It is concluded better mineral geochronometer, compared zircon, determine palingenetic-anatectic granitoids. Unlike usually inherits relict nuclei parent rocks, an exception. However, ideal geochronometer determining time endogenous geological processes. Since crystallization depends on activity calcium environment, same rock association rocks different composition, may crystallize at times. combination radiometric studies monazite, together with zoning their crystals, provides ample opportunities duration