Gold-Bearing Placer Assemblages in the East of the Siberian Platform: Origin and Prospects

For the first time, based on a study of the typomorphic features of placer gold and its distribution patterns, the predicted gold potential of the east of the Siberian Platform is substantiated. The identified morphological and mineralogical–geochemical indicators in placer gold have made it possible to establish the genesis of placers (alluvial, aeolian, etc.) and predict the types of primary sources. Gold-bearing placers were formed from ore assemblages that do not form bed placers. This explains the noneconomic placers recommended for complex diamond, gold, and platinum mining. Detection of Witwatersrand-type gold-bearing conglomerates is problematic, since there are no geological prerequisites for their formation in a region. For the east of the Siberian Platform, the following assemblage types of primary gold sources have been identified: low-sulfidation gold–quartz, gold–iron–quartzite, gold–copper–porphyry, Precambrian gold–platinoid and gold–silver, gold–rare-metal, gold–sulfide–quartz of Mesozoic ore formation stages. All of these correspond to certain geological and structural positions, and their identification contributes to more correct selection of methods of prospecting for deposits. The predicted types of primary sources, except for gold–platinoid, are not associated with mafic magmatism. A new source of ore gold has been established in the ultramafic alkaline carbonatite complex of the Tomtor massif. Promising objects are Carlin-type gold–sulfide quartz ore occurrences, predicted in terrigenous carbonate sequences spatially confined to deep-seated faults, repeatedly rejuvenated in the Mesozoic–Cenozoic, as well as Cripple Creek–type gold–silver occurrences in the Vilyui and Udzha paleorifts, where andesite–dacite volcanism had occurred.