Local Factors of Coastal-Marine Rare-Metal-Titanium Placers Formation

Local factors of formation of coastal-marine rare-metal-titanium placers were analyzed for creation of the search-oriented geological-dynamic model that allows predicting the prospects of rare-metal-titanium placer mineralization. The influence of the factors on the structure, composition, localization of placer concentrations within sedimentation basins, as well as the dynamic interaction of these factors during the formation of productive sediments was investigated. Based on the work of previous researchers who have studied in detail the issues of controlling the formation of these placers at the historical-geological and regional structural-tectonic level, a qualitative model of the formation of placer concentrations on local areas of the rank of districts, clasters, fields and specific placer bodies has been created, which can be the basis for creation of search-orientated model of the deposit and planning exploration and evaluation work. The following factors of the placer formation were studied: hydrodynamic – characterizing the types and mechanisms of placer concentrations (littoral and sublittoral) within the dynamically active coastal zone; lithodynamic – depending on the abrasion-accumulative regime of the coast and the parameters of the long-shore sediment flow; structural–dynamic – determining the possibility of the formation of economically significant productive deposits and their localization; and the factor of transgressive-regressive regime a basin that determines the structure of placer bodies and their transformation at the post-sedimentation stage. Large economically significant rare-metal-titanium placer deposits are formed only in conditions of joint realization of the positive potential of these factors. The developed qualitative model can serve as a basis for the process of digitalization of the forecasting of placer mineralization of this type.