Nanoparticale of ore minerals in disseminated multi-metal mineralization of Ducat ore district (North-East Russia)

Nanoparticles (size below 100 nm) of different minerals are found in disseminated mineralization of Ducat ore district (unique Au-Ag deposit) in associations with the combined-stratified minerals. The nanoparticles were identified as by chemical composition (scanning electron microscope JSM-5300, resolution 4 nm, fitted with energy-dispersion spectrometer Link ISIS), as well by the character of corresponding electron X-ray micro-diffraction patterns (electron microscope JEM-100C fitted with X-ray energy-dispersion spectrometer Kevex-5100). Formation of a large number of nanoparticles at the mineral crystallization centers is attributed to spontaneous fluid super-saturation caused by sharp pressure and temperature decrease at the near-surface layers of the deposit.