Dating according to zircon crystalline substance

The technique of extraction of purely crystalline substance is developed and the closed state of its uranium-lead system is investigated. The investigations are carried out for the purpose of impoving the uranium-lead method of dating geologic processes on zircons. As samples zircons of monomineral fractions from a number of geologic formations of the Baltic and Aldan shields have been used. It is shown that natural zircons with the age discordance characteristic of them comprise crystalline substance phases with nonbroken in the length of enormous stretches of time uranium-lead systems. The developed technique of crystalline phase separation presents new possibilities of application of dating uranium-lead method according to zircons. Obtaining of coinciding trustworthy age values permits practically to confine oneself to the analysis of one sample while the interpretation of momentarily changed uranium-lead relationship requires isochrone construction by several samples and proofs of trustworthiness of calculated dating