Diamonds in old sedimentary rocks and their source (on the basis of Yakutia kimberlite province)

Abstract

This study provides the results of a complex investigation of a number of kimberlite bodies with halfindustrial diamond content in several regions of the Siberian platform. This allowed us to establish the typomorphic features of the mineral. Diamonds from halfindustrial diatremes of Daldyn-Alakitsky and VerkhneMunsky diamondiferous regions are characterized by the prevalence of crystals with rhombic dodecahedral habit at high content of typical rounded diamonds, being an unfavorable factor of high diamond content. Differences in diamond features between individual kimberlite bodies are less pronounced than between diamondiferous regions, confirming the upper mantle heterogeneity in various parts of the platform. Prevalence of laminar crystals of octahedral, rhombic dodecahedral and transitive between them habits in pipes of the peripheral part of the Siberian platform (pipe Malo-Kuonapskaya) is indicative of the absence of horizontal zonation in alteration of typomorphic features within the investigated territory. Examples of using typomorphic features of diamonds are shown for forecasting kimberlite with high-diamond cobtent within Central-Siberian sub-provinces (Malobotuobinsky, Daldyn-Alakitsky, Morkoka and Sredne-Markhinsky regions, Lena-Anabar (Kyutyungdinsky region) and Tunguska (Baikitsky region)).