Texture and structure features of yakutites from placers of the Anabar diamondiferous region

Ugapeva S. S., Molotkov A. E., Gromilov S. A., Afanasiev V. P., Pavlushin A. D., Yelisseyev A. P., Popov V. I.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2022. V. 151. N 1. P. 15-28

https://doi.org/10.31857/S0869605522010105

Language: Russian

Abstract

New data on the study of structure features of polycrystalline diamond (yakutites) from placers of the Anabar diamondiferous region by X-ray and optical spectroscopy are presented. It is established that all studied samples are fine-grained (up to 1 microns) polycrystals. The diffractograms of most samples show reflexes associated with lonsdaleite defects presented in the diamond structure. It is shown that the yakutites are inhomogeneous: diffractograms of different parts of diamond aggregates show different reflections of texture and the presence of micrograins with a monocrystalline structure. The appearance of a “bell” in the single-phonon region of IR spectra indicates defects in the crystal structure of yakutites and a significant structural stress. The aggregated nitrogen line in the photoluminescence spectra of yakutites is absent. It suggests that they were ejected outside the crater after the solidphase synthesis stage and a fairly rapid cooled.

Keywords: impact diamond, polycrystalline aggregate, spectroscopy, X-ray, Siberian platform, yakutites