Инд. авторы:	Khromova E.A., Doroshkevich A.G., Sharygin V.V., Izbrodin L.A.
Заглавие:	Compositional Evolution of Pyrochlore-Group Minerals in Carbonatites of the Belaya Zima Pluton, Eastern Sayan
Библ. ссылка:	Khromova E.A., Doroshkevich A.G., Sharygin V.V., Izbrodin L.A. Compositional Evolution of Pyrochlore-Group Minerals in Carbonatites of the Belaya Zima Pluton, Eastern Sayan // Geology of Ore Deposits. - 2017. - Vol.59. - Iss. 8. - P.752-764. - ISSN 1075-7015. - EISSN 1555-6476.
Внешние системы:	DOI: 10.1134/S1075701517080037; WoS: 000426727900009;
Реферат:	eng: Pyrochlore-group minerals are the main concentrators of niobium in carbonatites of the Belaya Zima alkaline pluton. Fluorcalciopyrochlore, kenopyrochlore and hydropyrochlore were identified in chemical composition. Their main characteristics are given: compositional variation, morphology, and zoning. During evolution from early calcite to late ankerite carbonatites, the UO2, TiO2, REE, and Y contents gradually increased. All carbonatite types are suggested to contain initial fluorcalciopyrochlore. However, in calcite-dolomite and ankerite carbonatites, it is partially or completely hydrated due to hydrothermal processes at the late stage of the pluton. This hydration resulted in the appearance of kenopyrochlore and hydropyrochlore due to removal of Ca, Na and F, and input of Ba, H2O, K, Si, Fe, and probably U and REE. At the last stage of the pluton, this hydrated pyrochlore was replaced by Fe-bearing columbite.
Ключевые слова:	RUSSIA; GENESIS; SUPERGROUP; COMPLEX; SIBERIAN CRATON; ZAIRE; carbona-tites; hydropyrochlore; kenopyrochlore; fluorcalciopyrochlore; pyrochlore group; Belaya Zima massif; LUESHE;
Издано:	2017
Физ. характеристика:	с.752-764