Features of the composition and formation of diamond placers in the marginal parts of ancient cratons (on the example of the North-East of the Siberian platform)

Summarizing a significant amount of factual material on the complex study of diamond, we have prepared its characterization in the modern strata of the marginal parts of the main diamondiferous regions of the Siberian Platform. The established characteristics on the morphology, coloring, solid inclusions, internal structure, photoluminescence, as well as the impurity composition of diamond, testifies to a multiple number of the primary sources of diamonds from placers and the presence of new, yet undiscovered kimberlite bodies, including those with high content of the useful component, within the region. The studied diamonds from modern placers in the diamondiferous areas of the Leo-Anabar subprovince are relatively homogenous and, in general, are close to the crystals from the older secondary reservoirs surrounding the placers. On the whole, the described placers and diamond occurrences are characterized by a low diamond content of kimberlite type. The presence of relatively “fresh” diamonds of the Lower Lena type in modern placers of this region (without mechanical wear and weakly ferruginized stones) is also a distinctive feature of the modern placers of the region. The typomorphic features of diamonds obtained during the research can be successfully used for zoning of the area concerned in the course of geological prospecting works.