MARINE AND CONTINENTAL LOWER PERMIAN EVAPORITES OF THE PRYPIAC' TROUGH (BELARUS)

Abstract

Sakmarian evaporites which include gypsum, anhydrite, halite, carnallite, kieserite and bischofite occur in the Prypiac' Trough (Belarus) within the lower and upper parts of one lithostratigraphic unit, the Svaboda Suite. The lower part of Svaboda Suite is up to 143 m thick and is composed of rock salt with interbeds of red claystones–siltstones and potassium–magnesium and magnesium–sulfate salts which are correlated with the lowest potassic salts of the Sakmarian Kramators'k Suite of the Dnipro-Donets Basin. These salts originated from precipitation from marine brines. Salts occur in a very limited area, and the occurrence of sulfate facies is much wider. The upper part of the Svaboda Suite (up to 520 m thick) is composed of interbedded mixed halite–siliciclastic and terrigenous deposits. There were two major sources of solutions flowing into the continental basin in which the subsuite was formed: meteoric (and continental) waters, and brines derived from the dissolution of Devonian salts. The distribution of the mixed halite–siliciclastic facies was related to tectonic dislocations that controlled the depocenter and the outflow, from the underlying Famennian deposits, of the major volume of salt into the intensively growing salt domes. Accordingly, the tectonic framework was the major control on the evaporite basin during deposition of the upper part of the Svaboda Suite.