X-RAY LUMINESCENCE AND THE REE DISTRIBUTION IN FLUORITES OF SURANSKOYE DEPOSIT (THE SOUTH URALS)

摘要

Distribution of REE and TR_(Ca)~(3+)-centers were studied by neutron-activation analysis (NAA) and X-ray excited optical luminescence (XEOL) methods in samples of fluorites differing in color, texture and structural characteristics. types of mineral parageneses. The samples have been taken from different ore bodies and host rocks of Suranskoye deposit (the South Urals). The study has shown that REE concentrations in fluorite varies within three orders of their values. In the purest fluorite varieties, the total REE Content is extremely low: down to 1-2 ppm. It is comparable with parameters of the rough crystal material from the best optic fluorite deposits in Russia. There were two main types of TR_(Ca)~(3+)-centres composition revealed in the studied samples: C-type, characteristic chiefly for cases of 《difficult》 growth, and G-type - in cases of 《free》 growth. According to analysis of specific mineral parageneses and composition of TR_(Ca)~(3+)-centres there were five main stages of fluorite mineralization during the Suranskoye deposit formation. Therefrom, the northern part of deposit ought to be risen for several dozens meter relatively to its southern flank. There is also some unusual cryptocrystalline variety of the mineral widespread in the mere fluorite and sellaite-fluorite ores of the deposit. Possible mechanisms of its formation are discussed.