Comparative characteristics of diamonds from areas with a high density of kimberlite bodies

Abstract

Background. This paper presents a comparative study into diamonds from kimberlite bodies of the Verkhnemunsky field (Zapolyarnaya, Novinka, Komsomolskaya-Magnitnaya and Poiskovaya), the results of which allow these minerals to be distinguished from those found in other fields of the Siberian platform. Diamonds from the Zapolyarnaya kimberlite pipe are characterized by an increased prevalence of dodecahedroids with shagreen and plastic deformation bands, mainly of a violet-brown color. A significant part of these diamonds contains cavities. In this respect, diamonds from the Zapolyarnaya kimberlite pipe are similar to other bodies of the Verkhnemunsky kimberlite field (Komsomolskaya-Magnitnaya, Novinka and Poiskovaya) and different from diamonds mined at the Malo-Botuobinsky, Daldyn-Alakitsky and Sredne-Markhinsky diamondiferous areas.Aim. To analyze the characteristics of diamonds from the Verkhnemunsky field with a high density of kimberlite bodies.Materials and methods. The research was based on a large amount of data and materials collected over long-term prospecting and exploration works carried out by industrial and research organizations in Western Yakutia. A comprehensive study of diamonds was conducted under the guidance and participation of the authors.Results. Kimberlite ore bodies in the region under study were found to differ from similar ore bodies of the central fields (Mirninsky, Daldynsky and Alakit-Markhinsky) by a low content of xenoliths of sedimentary rocks, many of which underwent high-temperature metamorphism. In general, the kimberlite ore bodies of the field are characterized by relatively weak secondary changes. Therefore, the largest part of the kimberlites of individual diatremes (Zymnyaya, Komsomolskaya-Magnitnaya, Novinka and Legkaya) preserve fresh olivine of the second generation, which is usually replaced by later monticellite and periclase.Conclusion. Diamonds from the Verkhnemunsky field are characterized by a set of typomorphic characteristics, which can be used to differentiate them from minerals in other Yakutia deposits. The main typomorphic characteristics of Zapolyarnaya diamonds include the pronounced predominance of dodecahedroids with shagreen and plastic deformation bands, mainly of a violet-brown color and numerous cavities. In terms of this feature, these diamonds are close to other kimberlite bodies of the Verkhnemunsky field (Komsomolskaya-Magnitnaya, Novinka and Poiskovaya) but different from those in the Daldyn-Alakitsky, Malobotuobinsky and Sredne-Markhinsky diamondiferous areas.