Karst role in the formation of diamond placers of the Muno-Markhinskii interfluve (Yakutsk diamond-bearing province, Russia)

The paper is devoted to the karst role in the formation of aureoles of kimb erlite indicator minerals (KIM) and diamond placers in the modern alluvium of the Muna-Markha interfluve. Its territory is open, i.e., the Lower Paleo zoic rocks hosting kimberlites and kimberlites themselves are exposed on th e surface. Widely developed karst depressions are demonstrated to be the ma in suppliers of KIM and diamonds to the watercourse alluvium. These karst d epressions were filled with Jurassic sedimentary material with KIM concentr ations, which was mixed with authigenic iron minerals, i.e., limonite, magn etite, and hematite. This interpretation explains the high contrast in KIM distribution; i.e., sites with extremely high KIM concentrations alternate with watercourse areas devoid of heavy minerals. The revealed role of karat in KIM aureole formation in the open areas required an alteration of the p anning sampling scheme, which was significantly improved. The kimberlite bo dies of the Nakyn field located under the Jurassic sedimentary cover to the cast from the Muna-Markha al ea, are accompanied by karst depressions. Som e karst depressions in the open areas may also he associated with kimberlit es. Therefore, the detailed study of karst and the comprehensive interpreta tion of magnetic anomalies are necessary for the discovery of kimberlite bo dies. Most of these anomalies are: produced hy karat structures.