Nature of diversity of diamonds in kimberlites

Shkodzinskiy V. S., Beskrovanov V. V.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2019. V. 148. N 4. P. 110-124

https://doi.org/10.30695/zrmo/2019.1484.08

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Language: Russian

Abstract

The one-way evolution of inclusions in diamonds and its ultra-long duration (more than 2.8 Ga) provide evidence that the crystallization of diamonds took place from the fractionated peridotitic layer in the global magmatic ocean. Diamonds were formed as a result of accumulation of carbon in residual kimberlitic melts. The increment of SiO₂ concentration in the melts caused increase in its viscosity, decrease of diffusion velocity and degree of carbon oversaturation. These resulted that the layered diamond crystallization mode was changed by the radial one, diamond octahedrons transformed into rhombic dodecahedrons and cubes, varied sculptures were created on diamond crystals faces.

Key words: genesis of diamonds and kimberlites, magma ocean, mantle