naa a22 4500 510736289 CHVBK 20180411092754.0 cr unu---uuuuu 180411e20131201xx s 000 0 eng 10.1134/S107570151307012X doi (NATIONALLICENCE)springer-10.1134/S107570151307012X Composition and chemical microprobe dating of U-Th-Bearing minerals. Part 2. Uraninite, thorite, thorianite, coffinite, and monazite from the Urals and Siberia [Elektronische Daten] [S. Votyakov, V. Khiller, Yu. Shchapova, Yu. Erokhin] To develop further chemical microprobe timing of U-Th-bearing minerals on the basis of upgraded measurement techniques and special age calculation, uraninite, thorite, thorianite, coffinite, monazite from several localities in the Urals and Siberia have been dated. The samples were taken from granitic rocks of the Pervomaisky pluton in the Central Urals; the pre-Jurassic basement of western Siberia and Yamal Peninsula; carbonatite-like dolomite from the Karabash ultramafic massif in the Southern Urals; granitic pegmatites of the Lipovsky vein field; and quartz-sulfide veins of the Pyshma-Klyuchevsky Cu-Co-Au deposit in the Central Urals. Scrutiny of the composition and chemical heterogeneity of mineral grains is a necessary stage of chemical dating aimed at the estimation of the degree of closeness of the U-Th-Pb system and unbiased screening of analytical data. The condition (Si + Ca)/(U + Th + Pb + S) ∼ 1 was used as evidence for significant secondary alteration of monazite; the negative correlation between Pb and Th or U +Th in uranitite was used for the same purpose. The positive correlation between Pb and U, along with low concentrations of Ca, Si, and Fe admixtures, implies that the stoichiometric composition of thorite is close to 100%. The reliability and accuracy of the chemical dating of minerals with high contents of radioactive elements can be enhanced by using bimineralic or multimineralic isochrons, e.g., monazite-uraninite, uraninite-coffinite, etc. The results obtained have been compared with the available isotopic ages of the studied minerals; the compared data are satisfactorily consistent. Pleiades Publishing, Ltd., 2013 Votyakov S. Zavaritsky Institute of Geology and Geochemistry, Ural Division, Russian Academy of Sciences, Pochtovyi per. 7, 620075, Yekaterinburg, Russia aut Khiller V. Zavaritsky Institute of Geology and Geochemistry, Ural Division, Russian Academy of Sciences, Pochtovyi per. 7, 620075, Yekaterinburg, Russia aut Shchapova Yu Zavaritsky Institute of Geology and Geochemistry, Ural Division, Russian Academy of Sciences, Pochtovyi per. 7, 620075, Yekaterinburg, Russia aut Erokhin Yu Zavaritsky Institute of Geology and Geochemistry, Ural Division, Russian Academy of Sciences, Pochtovyi per. 7, 620075, Yekaterinburg, Russia aut Geology of Ore Deposits Springer US; http://www.springer-ny.com 55/7(2013-12-01), 515-524 1075-7015 55:7<515 2013 55 11477 https://doi.org/10.1134/S107570151307012X text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1134/S107570151307012X text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Votyakov S. Zavaritsky Institute of Geology and Geochemistry, Ural Division, Russian Academy of Sciences, Pochtovyi per. 7, 620075, Yekaterinburg, Russia aut NATIONALLICENCE 700 1- Khiller V. Zavaritsky Institute of Geology and Geochemistry, Ural Division, Russian Academy of Sciences, Pochtovyi per. 7, 620075, Yekaterinburg, Russia aut NATIONALLICENCE 700 1- Shchapova Yu Zavaritsky Institute of Geology and Geochemistry, Ural Division, Russian Academy of Sciences, Pochtovyi per. 7, 620075, Yekaterinburg, Russia aut NATIONALLICENCE 700 1- Erokhin Yu Zavaritsky Institute of Geology and Geochemistry, Ural Division, Russian Academy of Sciences, Pochtovyi per. 7, 620075, Yekaterinburg, Russia aut NATIONALLICENCE 773 0- Geology of Ore Deposits Springer US; http://www.springer-ny.com 55/7(2013-12-01), 515-524 1075-7015 55:7<515 2013 55 11477 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 494164700 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer