First Evidence of Nanodiamond Clusters Formation in Shungite in Connection With Seismogenic Dynamic Shear

The first evidence for the natural transformation of originally amorphous carbon into graphite and diamond nanoclusters under the influence of high-speed dynamic shearing and the associated frictional heating of the carbonaceous substratum is presented in the example of Karelian shungites and seismogenic slickensides identified in them. Approximate estimates of the PT parameters of these structural, material, and phase transformations are given, and their position on the phase diagram of carbon is noted.