Genesis, Features of Mineral Composition, and Problems of the Development of Rare Metal-Titanium Placers in the West Siberian Megaprovince

摘要

The coastal-marine rare metal-titanium placers of the West Siberian megaprovince were formed in a relatively short Eocene-Late Oligocene interval. A similar formation mechanism and commonality of primary sources of ore matter were responsible for the single type and similarity of mineral composition of placers in the megaprovince. Based on the comparison of various characteristics of these placers, common factors determining their industrial value were identified: the structural plan and tectonic movements of the platform basement governed the facies zonation, and lithological and technological characteristics of placer components and host rocks; and postdepositional tectonic processes influenced the position (depth) of placers in the sedimentary cover and the characteristics of ore sands (degree of their secondary supergene alterations). The geological factors, which make it possible to predict mining parameters of placers, technological characteristics of ore sands, quality of mineral concentrates, and geoeconomic indicators of the rare metal-titanium placer deposits, are defined.