Finds the evolution of mineral deposition in southern Tuva, indicating high-temperature genesis of ore formation.
The chemistry of mineral assemblage formation indicates that the subsequent deposition of minerals occurred upon a significant decrease in acidity of initially sharply oxidized medium and its change into reduced one. The appearance of bastnaesite arose from decomposition of a major part of soluble REE compounds as the result of sharp decrease in Fe concentration in solution and its precipitation in the form of hematite. The spectra of the normalized REE distribution before and after crystallization of bastnaesite indicate the predominant isomorphous replacement of Ca ions with medium and heavy REE in fluorites of early generations and in siderite, disseminated occurrences of lanthanoids typical of other minerals, which show quantitative ratios of elements in solution at the moment of crystallization of mineral carrier. The conclusion is made on high-temperature genesis of ore deposition from one and the same mineral-forming medium evolved in time.
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Kulik et al. (1992) studied this question.
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