Home – Home – Jornals – Russian Geology and Geophysics 2019 number 6

This is a pioneering study on lateral zoning of groundwater chemistry and authigenic mineralogy in the Oxfordian regional reservoir of the Nadym–Taz interfluve. According to thermodynamic calculations, the nonequilibrium–equilibrium water–rock system lacks equilibrium with primary magmatic minerals, such as al-bite, anorthite, and microcline, though the water is moderately saline (up to 63.3 g/L) and has been in interaction with rocks for ~165 million years. Authigenic minerals form continuously and successively (kaolin-ite–montmorillonite–illite–micas–chlorite–albite–microcline) fr om waters that have certain рH and contents of SiO2, Al, Na, K, Ca, and Mg. The equilibrium of groundwater with primary aluminosilicate minerals impinges on a carbonate barrier, and almost all rocks are more or less strongly carbonatized. Authigenic mineral assem-blages from the southern Nadym–Taz interfluve include kaolinite unlike those from the northern part of the re-gion wh ere albitization is more common. Authigenesis generally decays in the eastern direction.