Experimental and computational model of pyrite-sphalerite-barite assemblage formation under the mixing of fluids

Laptev Yu. V.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2019. V. 148. N 1. P.117-126


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Language: Russian 


Experimental and thermodynamic study of the formation conditions of sulfates and sulfides under the mixing of fluids has been carried. This geochemical process is very important for modern sulfide ore formation at the floor of the oceans. Experimental procedure was based on the scheme H2S (H2SO4) + МеСl2MeS (MeSO4) + 2HCl. During experiments, sphalerite and pyrite, together with barite, were synthesized by mixing aquatic solutions of chloride of zinc, iron, and barium with sulfide-containing solutions at temperature of 200—275 °C and pressure of 100 bar. Experimental data on the composition of fluid and solid phases were used to validate a computational model. To calculate the composition of non-ideal solid solution of sphalerite (ZnS-FeS), the Margules asymmetric model was applied. Contents of iron in sphalerite calculated through this model and determined from experiments at 243 °С are 1.5 and 1.0 wt % correspondingly. The good similarity of these values indicates the feasibility of the proposed model of deep-sea sulfide ore formation in ocean floor structures.

Key words: experiment, pyrite, sphalerite, barite, mixing of fluids