Mihalchenko I.I.¹ Andreev O.V.²
1 – Government organization «Institute of the Environmental Geochemistry of the National Academy of Sciences of Ukraine»
2 – Taras Shevchenko National University of Kyiv, Educational-Research Institute «Institute of Geology»
Language: Ukrainian
Geochemistry and ore formation 2017, 38: 32-49
https://doi.org/10.15407/gof.2017.38.032
In this paper, we present new result, that the crystals of relict magmatic monazite of initial granite, which tested hydrothermal metasomatism transformations, are included in mineral composition of thorium-uranium ore-bearing albitites Novooleksiivka ore deposit and hydatogenesis monazites of hydatogenesis. Chemical composition of hydrothermal monazites in «ore»albitites differs in the large values of measuring of C(La2O3) and C(Ce2O3) and considerably less C(Pr2O3), C(Nd2О3), C(ThO2), what in magmatic monazites of initial granite and the least changed magmatic monazites х of albitites. Monazites were unsteady minerals during hydrothermal metasomatism transformations. By the main factors of decomposition of magmatic monazites and, accordingly, dissociating from him, in particular, Th at formation of albitites appears: resaturation of fluid of P (PO43-(?)), saturation of Са and speed of infiltration of fluid. Exposure of hydrothermal monazite with anomalous C(La2O3) and correlation of C(La2O3)/C(Ce2O3) in «ore» albitites х with the signs of increase-diminishing of mass parts of rare-earth elements in hydrothermal relict monazites testifies to the them lixiviating, migration, partial fractionating and separate besieging. At mineral level of organization of geological substance a previous conclusion is confirmed about the division of geochemical history to thorium from history of lanthanum and cerium during formation of thorium-uranium ore-bearing albitites of the Novooleksiivka ore deposit. Formation of enhanceable concentrations to thorium with uranium, which together enter in the complement of hydrothermal-metasomatism minerals-concentrators of these chemical elements in albitites testifies to migration of uranium at the degree of oxidization of U4+.
Keywords: monazit, uranium, thorium, albitite, Novooleksiivka ore deposit.
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