Abstract

Of the 26 Devonian evaporite basins presently known in the world II are salt basins. A comparative analysis of these basins suggests the presence of large and vast evaporite seas where areas of salt deposits accounted for a third or even half of the entire sedimentary basin. According to their shape or outline the basins were subdivided into three groups. Some evaporite basins were short-lived. The Devonian salt basins show a great deficiency of rock salt compared to the recorded volumes of gypsum (anhydrite) and a deficiency of potash salts relative to rock salt. Huge masses of concentrated brines accumulated in them. The Devonian salt formations belong to the chloride class and fall into the halite or halite-sylvite-carnallite families. The above features may, perhaps, be attributed to peculiar paleogeography responsible for wide recurrent interchanges of salt basins with the ocean. Evaporite deposition was also affected by freshwater runoff. All Devonian evaporite basins were typically inland seas occupying continental margins. Regions with evaporite deposition incorporated transitional areas with islands, shoals and reservoirs connected with straits responsible for unidirectional circulation of sea water in salt basins.