Home – Home – Jornals – Russian Geology and Geophysics 2003 number 10

The Nazarovskoe deposit lies in the Ozernoe ore cluster within a relic of the Late Cambrian volcanosedimentary rocks in the field of Late Paleozoic granitoids. It is confined to the most elevated tectonic block of the Ozernoe relic and is situated above the crest-like uplift of leucocratic granites. Its main mineralization is represented by multistage stratiform deposits of recrystallized zinc-pyrite ores and Fe-Mn-oxide ores that occur in tuffaceous terrigene carbonate rocks skarned and altered to a varying degree. There is a vestige of hydrothermal-sedimentary ore deposition related to Lower Cambrian volcanism. Gold mineralization is found chiefly in skarned ore deposits and within partly hydrothermally altered country rocks. Gold occurs in various mineral assemblages and displays different structural relationships. According to mineralogical data, its higher contents in pyrite, pyrrhotite (to 10 ppm), and sphalerite (to 3.6 ppm) are due to a mechanical impurity. Gold is directly correlated with bismuth and silver. It was deposited at the stage of recrystallization of stratiform ores during the contact metamorphism as well as at later stages in connection with the formation of galenite mineralization and quartz-carbonate veinlets. The composition of native gold at the deposit ranges from high-fineness gold to kuestelite. The gold mineralization is younger than the stratiform sulfide ores. The main portion of gold was delivered by hydrothermal solutions along the subconcordant fault zone and is related to granitization of Lower Cambrian ore-bearing volcanosedimentary rocks. The magmatogenic hydrothermal component in the deposit ores has been established from such typomorphous elements as Mo, Co, Bi, and Be.