One of the probable mechanisms that controls the composition of highly mineralized chloride groundwaters is studied using physicochemical numerical simulations of equilibria in water-rock systems. Concentrated brines in the Olenek cryoartesian basin in the northeastern Siberian Platform are determined to be undersaturated with respect of major rock-forming minerals, which suggests that the metamorphosed sedimentary brines should have been diluted by meteoric waters during a certain evolutionary episode of the permafrost zone of the basin in the Late Pleistocene and Holocene.
