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Geology of Upper Permian (Zechstein) evaporites in the central Fore-Sudetic Monocline (SW Poland)

Authors: 
Grzegorz CZAPOWSKI, Łukasz NOWACKI, Jacek CHEŁMIŃSKI, Andrzej GŁUSZYŃSKI, Leszek SKOWROŃSKI
Citation: 
Salt Review, 2018, 14: 29–53
Abstract: 

Analysis of recent extension and thickness of Upper Permian (Zechstein) evaporites (sulphates and chlorides) in the area of central Fore-Sudetic Monocline, based on data from 635 archive boreholes, enabled to reconstruct the possible palaeographic images of both sulphate and chloride basins, represented some evaporitic lithostratigraphic units of four Zechstein cyclothemes. Sulphates and chlorides of PZ1 and PZ3 cyclothemes as well as sulphates of PZ2 cyclotheme (Basal Anhydrite [A2] unit) have deposited in the basins with distinctly varied bathymetry, where existed the shallow (barrier and shoals) and the deeper (basins) parts. Their accumulation realized the depositional scheme of the „infill” type of evaporitic basin, after which dominant infill by chlorides took place in the deeps of former sulphate basin with differentiated bathymetry accentuated by other accumulate rate of sulphates (a higher on bottom shoals and slower in the deeps). Local occurrence of other evaporate units of PZ2 and PZ4 cyclothemes eliminated creation of similar palaeogeographic images for their depositional basins. Commented evaporite units were characterized by data representative for their age equivalents drilled in the nearest areas because of extremely rare core data form the study area. Disjunctive tectonics (fault systems and two tectonic grabens) modified in a different rate the primary extent of studied evaporites as well as it was responsible for their local thickness increase in the near-fault zones.