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oa New (?) calcium-thorium-uranium silicate (calciothorouranite) from thorium-uranium ore albitites from the Novooleksisvka ore occurrence, the Ukrainian Shield
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Geoinformatics: Theoretical and Applied Aspects 2020, May 2020, Volume 2020, p.1 - 5
Abstract
The article presents the results of a study of calcium-thorium-uranium silicate, which was discovered by the authors in the Precambrian thorium-uranium albitites of the actinolite-diopside group of metasomatic facies of alkaline sodium metasomatites of the Novooleksiivka ore occurrence of the Partizansky ore field of the Central-Ukrainian ore district. It is shown that the main components of the chemical composition of the mineral are UO2, SiO2, ThO2, CaO. The usual impurities are FeO, Y2O3, Al2O3, BaO. The content of PbO in the different crystals vary within (3.05–11.6) %. The chemical composition of the mineral is not constant, apparently due to significant epigenetic transformations. The signs of transformations are manifested of the presence of reaction boundaries with the epidote (the latter seems to be “eating” this radioactive mineral), transformations in region of boundaries with the albite, of the presence of numerous cracks, which are filled with uranium black with a significant impurity Pb. The detected calcium-thorium-uranium silicate differs by high content of ThO2, CaO, Y2O3 from Calciothorite, Nenadkevite, Uranophane, Coffinite, and a high content of UO2, CaO, Y2O3 from Calciothorite. Probable crystal-chemical formula of calcium-thorium-uranium silicate – (Ca2,U,Th,) [SiO4]∙nH2O. In the case of proving that this silicate is a new mineral, we are proposed to call this mineral calciotorouranite. The existence of an isomorphic series of calciotorite-calciocoffinite (the latter is not yet known) is assumed.
