Silicate Inclusions in Metamorphic Diamonds from the Ultra-High Pressure Kokchetav Complex (Kazakhstan)

Mineral inclusions in cubic diamonds from garnet-clinopyroxene rock of the Kokchetav massif were studied. The coexistence of fluid and silicate inclusions in the central part of the diamond of the G0 sample was revealed by means of transmission electron microscopy. Silicate inclusions are represented by intergrowths of garnet and mica, which are spatially related with the carbonate and fluid inclusions. The first finding of silicate inclusions in the cubic diamonds from the UHP complex discovered over 50 years of their study is apparently due to a selective capture of the silicate minerals in the process of the diamond crystallization from the carbonate-bearing C-O-H fluid. The processes of diamond crystallization in the metamorphic deeply subducted rocks and upper mantle rocks, which are carried to the surface as xenoliths by kimberlite melts, have much in common.