ИСТИНА

Melt/fluid inclusions in diamonds provide important evidence for mantle diamond-forming fluids or melts. By now, the major characteristics of the composition of microinclusions have been analyzed in diamonds from several kimberlite provinces and pipes worldwide. Here we report the first data on the composition of parent diamond-forming melts for diamonds from the Arkhangelsk kimberlite province.After study of morphology, specific of the internal structure, the presence and distribution of micro-inclusions in diamonds 10 single crystals were selected from a representative collection consisting of 31 samples. Diamonds may be divided into two groups: cuboids and coated diamonds. The crystals have dirty-yellow or dark-grey colors and almost nontransparent due to contain micro-inclusions. Polished slices were prepared from these crystals. Application of IR-spectroscopy allowed to calculate the content of nitrogen defects, as well as the amount of water and carbonates in microinclusions. Application of IR-spectroscopy allowed to calculate the content of nitrogen defects, as well as the amount of water and carbonates in microinclusions. X-ray spectral analyses allowed to study the composition of fluid/melt microinclusions and showed that they were carbonate-silicate with significant variations between these two components. There is a constant presence of water, the proportion of which is maximal in silicate inclusions. Unlike the diamonds of South Africa and Canada, the absence of chlorides in melts is established for Arkhangelsk crystals. Comparison of the data obtained allowed to conclude that them similar to the diamonds of Yakutia, and the data most similar to that in diamonds from the Internatsional’naya pipe (Yakutia).