Isotopic composition of Carbon and Oxygen in sedimentation and epigenetic carbonates of the Lower Transitional member of the Verkhnekamskoe salt deposit

Abstract

In contrast to the carbonate-sulfate evaporites of the Syukeevskoe deposit and the salts of the Starobinskoe deposit, the formation of the salt stratum of the Verkh-nekamskoe deposit is assumed to involve melt water formed between the P2 and P3 glacial events. Comparison of host rocks and newly formed mineralization made it possible to show that the process of diagenesis in carbonate-argillaceous strata alternating with rock salt was difficult. Initially, there was a decomposition of dispersed plant detritus, which is confirmed by the lightening of the isotopic composition of carbon. After the interaction of sulfate-containing sediment with desalinated waters, the anhydrite was replaced by 16O-enriched calcite. The complete lithification and stratification of clay strata led to the formation of exfoliation cavities, in which halite-calcite veins of columnar structure were formed associated with the influx of brines from neighboring salt strata enriched in 18O.