COMPARATIVE-ANALYSIS OF ZIRCON SEPARATION TECHNIQUES FOR GEOCHRONOLOGICAL GOALS

Based on natural zircon specimens of different crystallization degree the experiments were carried out in respect of possibilities and const raints of recent techniques of separation of those specimen fragments which are least altered by secondary processes as only samples suitabl e for a mostly concordant age values. The considered techniques are as following: aeral grinding treatment; separation of heaviest mineral f raction; differential dissolution in hydrogen fluiride acid. Least dis cordant zircon specimens from crystalline samples and semicrystalline grains with sufficient fraction of the crystalline phase were separate d by use of differential dissolution. The comparison with other indepe ndent treatment techniques proves the absence of predominant uranium a nd lead removal is such procedure. This techniques could not be applie d to completely metamict zircons subjected to leaching of lead.