The geochemistry of calcium chloride brines in the oleniok cryoartesian basin (Siberian platform)

This article presents results of the physicochemical simulation of the water-rock system equilibrium and discusses a saturation degree of calcium chloride brines in the Oleniok cryoartesian basin. The analyses show that the chloride brines with salinity of 54–57 g/L are in the equilibrium (or quasi-equilibrium) state relative to the main sedimentary rock-forming minerals, but the strong brines (salinity above 300 g/L) are undersaturated relative to these minerals (calcite, dolomite, magnesite, strontianite, anhydrite, celestite, halite and sylvite). The non-equilibrium state of the water–rock system is due to brines dilution during the evolution of the cryolithozone in the Oleniok basin in the Late Pleistocene and Holocene. An additional water amount to reduce the brine salinity was generated during the ice transformation to the liquid phase due to ability of the brines to cause ice melting at negative temperatures and the high ice content in the ice-rich permafrost. The ice–brine interaction leads to dilution of concentrated solutions.