THE AGE AND PRIMARY NATURE OF XENOLITH PLAGIOGEISS IN GRANITES OF THE NOVOUKRAINSKY MASSIF

The anatomy of accessory zircon crystals from the bipyroxene plagiogneiss xenolith in the trachytoid granite of the Novoukrainsky Massif was studied using optical microscopy methods. most likely of the Kamian-Kostovac unit and the results of dating of accessory zircon crystals and multigrain measurements of accessory monazite crystals by the TIMS method. Zircon crystals are complex, represented by heterogeneous cores, usually with strongly rounded contours, characteristic of clastogenic crystals on which thin shells of younger zircon grow. The age of the central areas of zircon crystals was determined by the LA ICP MS method - 2068±22 million years. The time of monazite crystallization (2017.2±2.1 million years ago) is somewhat younger than the age of monazites from the granites of the Novoukrainsky massif.