On the nature, composition and gas content of epigenetic mineralization in the salt column of the Verkhnekamskoe deposit (on the example of the Usolsky mine)

Abstract

Research subject. The paper considers the tectonic position of the zone of epigenetic mineralization in the salt strata of one of the mines of the Verkhnekamskoye deposit, the gross and microelement chemical composition, gas content and component composition of gases. Materials and methods. To assess the composition of the original and epigenetic formations, structural and geological observations were carried out in mine workings, sampling, determination of the gross chemical composition (XRF, Bruker S8 Tiger spectrometer), trace elements (Aurora M90 inductively coupled plasma mass spectrometer), gas content and component composition of associated gases (gas chromatograph 450-GC company “Varian, Inc”). Results. It has been established that vein mineralization fills delamination cracks in the cores of the synclinal fold and is accompanied by zones of halite leaching and sylvite recrystallization. Further down the section, possible sources of K-oversaturated brines are recorded, which are generated in numerous small structures such as pop-ups or kink bands. The enrichment in light hydrocarbon gases, as well as easily soluble salts and mobile elements (KCl, CaCl 2 , MgCl 2 , Br, Rb, Li, Sr, Zn, Cu, Co, Te, Se, Sn, Pb), reflects their formation from sediment-brines mobilized during folding from sylvinite rocks. Conclusions. One of the mechanisms for the mobilization of fluids, salts, and trace elements in the salt column is characterized, which is associated with the folded appearance of small scattered chambers in the lower silyvinite bed KrIII and subsequent pulsating migration up the section along the synclinal bends of larger folds in the bed KrII. It is shown that in the process of formation of the zone of epigenetic mineralization, differentiation of small elements and gases occurs, which is associated with different sorption properties of halite, sylvin, and clay material.