Conclusions: Two processes of changes in the kimberlite rocks of the region were revealed. The first process is the phased conversion of olivine to high-temperature, then low-temperature serpentine. The second process is the degradation of serpentine with the simultaneous emergence of a series of swellable minerals, starting with saponite through a series of intermediate metastable mixed-layer formations, out of which the ordered variety of lyzardite-saponite, identified for the first time, was relatively more stable compared to other ordered mixed-layer phases of the trioctahedral type. This finding emphasizes the specific conditions of crust formation of the weathering kimberlites of the African region.
Keywords: weathering crust, kimberlites, volcanic-sedimentary formations, African continent.