МANTLE ZIRCON FROM THE UKRAINIAN SHIELD PLACERS AS INDICATOR OF KIMBERLITE NATURE OF DIAMOND

In the terrigenous sediments of the diamond-bearing Ti-Zr placer deposit of Samotkan (Ukrainian shield), a variety of mantle zircon was discovered, which can serve as an indicator of the kimberlite nature of the diamond. It is mainly presented by rounded almost colorless grains (0.05 ‒ 0.1 mm) with a strong diamond shine and high relief. By degree of crystallinity, color of luminescence, qualitative composition of oxygen-hydrogen defects ОН_n and owne defects of [SiO₄]^4- tetrahedra they are similar to crystals from kimberlite explosion tubes.The same spectroscopic parameters have the central cores of zonal zircon individuals from kimberlites. This discovered similliarity of spectroscopic parameters makes it possible to assume that zircon from placere is one of the earliest products of crystallization of the upper mantle melt.