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 calc-silicate 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.