Composition and Geodynamic Nature of the Protoliths of Diamondiferous Rocks from the Kumdy-Kol Deposit of the Kokchetav Metamorphic Belt, Northern Kazakhstan

The distribution of rare earth elements was analyzed in the Early Cambrian diamondiferous calcsilicate rocks and gneisses, calciphyres, and marbles of the Kumdy-Kol deposit. These data were compared with the lithogeochemical characteristics of the sedimentary assemblages of weakly metamorphosed Late Precambrian graphite-bearing sedimentary rocks of the Kokchetav metamorphic belt. The obtained results allowed us to suppose that the protoliths of the Kumdy-Kol rocks were compositionally similar to the Late Precambrian graphite-bearing terrigenous–carbonate and sand–shale sequences of the continental shelf of the Kokchetav microcontinent, some of which were transformed in a subduction zone into diamondiferous rocks.