Conditions of Formation of the Pavlik Gold–Sulfide–Quartz Deposit (Northeast of Russia) According to a Study of Fluid Inclusions

Abstract

The stockwork gold–sulfide–quartz ores of the Pavlik deposit (northeast of Russia) are formed mainly by homogeneous, low saline (9.4–4.3 wt %-eq. NaCl), essentially water–chloride fluid at temperatures of 275–330°C and a fluid pressure of 600–1840 bar. The fluid is characterized by a rather high CO2 content and a reduced methane content, with the ratio of CO2 : CH4 being 17–37.3. In the fluid, among the cations, the main role is played by Na and Ca, and K and Mg are in a subordinate amount. In addition, many trace elements were detected in the fluid composition: As, Li, Rb, Cs, Mo, Ag, Sb, Cu, Zn, Cd, Pb, U, Ga, Ge, Ti, Mn, Fe, Co, Ni, V, Cr, Y, Zr, Sn, Ba, W, Au, Hg, and rare-earth elements. The obtained data allow us to suppose that there was a decrease in the depth of ore formation during the formation of the deposit by 4–5 km due to the rise of the ore-bearing block. Attention is drawn to the low fluid pressures for a number of samples (330–140 bar), which may be associated with a separate stage of mineral formation. The ore-forming fluid of the Pavlik deposit in composition, temperatures and pressures shows similarities with the fluids of the neighboring Natalka and Rodionovsky deposits and has a great similarity with typical fluids of orogenic gold deposits. The information given in the article is of great practical importance for regional predictive metallogenic constructions, as well as prospecting and evaluation of gold deposits.