Zechstein evaporites, deposited in an intracratonic basin in the region of the present-day North Sea, which was separated by a structural barrier from the worlds oceans.
The entire basin originated as an area of inland drainage, which lay below sea level. Following an initial transgression, depositionion the central parts of the basin began in a deep-water setting, 200-300m deep.
Synsedimentary subsidence led to the accumulation of more than 2km of Zechstein carbonates, evaporites and siliciclastics over a period of 5 million years. Five major cycles are present that was controlled by eustatic sea level change.
Source Roger Suthren
Photograph of an ancient evaporite deposit
The basinal facies is evenly laminated carbonates and anhydrite sequences containing several interrelated nodular anhydrite horizons. Each of the depositional sequences starts abruptly with nodular/entrolithic anhydrites and grades up, via laminar anhydrite into laminar carbonate.
The nodular anhydrites are interpreted to have formed during initial stages of brine recharge when conditions were shallowest and most saline (Tucker, 1991).
This page was created by Pamela Williams