The Zechstein ( German either from mine stone or tough stone ) is a unit of sedimentary rock layers of Late Permian ( Lopingian ) age located in the European Permian Basin which stretches from the east coast of England to northern Poland. The name Zechstein was formerly also used as a unit of time in the geologic timescale , but nowadays it is only used for the corresponding sedimentary deposits in Europe.
17-705: The Zechstein lies on top of the Rotliegend ; on top of the Zechstein is the Buntsandstein or Bunter . The Zechstein is associated with the accumulation of large amounts of salt rock between 257.3 and 251.0 million years ago. The evaporite rocks of the Zechstein formation were laid down by the Zechstein Sea , an epicontinental or epeiric sea that existed in the Guadalupian and Lopingian epochs of
34-403: A sequence of strata defining a chronostratigraphic unit. Series are subdivisions of systems and are themselves divided into stages . Series is a term defining a unit of rock layers formed during a certain interval of time (a chronostratigraphic unit); it is equivalent (but not synonymous) to the term geological epoch (see epoch criteria ) which defines the interval of time itself, although
51-727: Is divided in the Silverpit Formation and Slochteren Formation , the last is an important reservoir for hydrocarbons . The German Bentheim Sandstone , which crops out in the Münsterland , is part of the Slochteren Formation. The Rotliegend of northern Germany is continuous with that of the Netherlands. In other parts of Germany contemporaneous basins exist, such as the Saar-Nahe Basin ,
68-495: The Magnesian Limestone . Just above the base of the Zechstein formation is a fairly thin layer of shale, or slate, where it has been metamorphized, known as the kupferschiefer for its high copper content. In its unmodified form, this layer is high in sulfur compounds that are typical of silt deposited in stagnant shallow marshland. Where faults have allowed mineral-rich groundwater to circulate through this layer,
85-616: The North Sea Oil province. In the southern gas basin, it forms the main cap rock to the gas fields with Rotliegend reservoirs. It also forms a reservoir in the Auk oilfield in the central part of the North Sea. Further north, the Zechstein salt becomes diapiric , forming salt domes which form the structure for several oil fields, such as Machar. Zechstein dolomites crop out near the coast of County Durham , England where they are known as
102-494: The Permian-Triassic extinction . The Zechstein is usually given the status of a lithostratigraphic group and as such encompasses a number of geologic formations . It consists of at least five depositional cycles of evaporite rocks, which are labelled Z1 to Z5, respectively. The lithologies found are halite ("rock salt"), anhydrite , dolomite , and shale . The Zechstein has significant economic importance in
119-525: The Wetterau or the Saale Basin . The Rotliegend of these different intramontane basins is not easy to correlate and the lithostratigraphy of each basin has its own divisions (groups and formations). Series (stratigraphy) Series are subdivisions of rock layers based on the age of the rock and formally defined by international conventions of the geological timescale . A series is therefore
136-799: The Permian period. The Zechstein Sea occupied the region of what is now the North Sea , plus lowland areas of Britain and the north European plain through Germany and Poland. The Zechstein Sea lay in the rain shadow of the Central Pangean Mountains to the south. At times the Zechstein Sea may have connected with the Paleotethys Ocean through southeastern Poland; the point is disputed by researchers. Though situated at
153-1145: The Upper Cretaceous and Lower Cretaceous Series, while the Carboniferous System is divided into the Pennsylvanian and Mississippian Series. As of 2008, the International Commission on Stratigraphy had not yet named all four series of the Cambrian . Currently series are limited to the Phanerozoic, but the ICS has stated its intention of subdividing the three systems of the Neoproterozoic ( Ediacaran , Cryogenian and Tonian ) into stages too. Systems can include many lithostratigraphic units (for example formations , beds , members , etc.) of differing rock types that were being laid down in different environments at
170-588: The deposition was restricted to the centre of the basin in the southeastern North Sea and northern Germany, this group is very limited in thickness in the Dutch subsurface. The upper group has a larger arial distribution since the basin had grown wider. In Dutch lithostratigraphy, the Rotliegend lies on top of the late Carboniferous Limburg Group and below the Zechstein Group . The Upper Rotliegend Group
187-580: The past not only been used to address the rock strata themselves, but also the time span in which they were formed (in which case the Rotliegend was considered a series or subsystem of the Permian). This time span corresponds roughly with the length of the Cisuralian epoch . In large parts of Pangaea , the last phases of the Hercynian orogeny were still ongoing during the start of the Permian. At
SECTION 10
#1732772118210204-585: The same time local crustal extension formed intramontane basins such as the large Permian Basin which covered parts of present-day Germany , Poland , Denmark , the North Sea , the Baltic Sea and the Netherlands . The early development of the basin went hand in hand with volcanism . Apart from these volcanic deposits the basin was filled by the erosional products of the Hercynian mountains to
221-402: The south: mostly sands and gravels deposited under an arid and warm climate. In the north of Germany and in the Netherlands, the Rotliegend is usually subdivided into two groups : a Lower Rotliegend Group (mostly volcanic rocks: tuffs and basaltic lavas ) and an Upper Rotliegend Group ( sandstones and siltstones ). During the formation of the lower group the basin was still small and
238-551: The sulfur has oxidized metal ions to metallic sulfide ores. From the Middle Ages into the modern era, this thin but widely dispersed constellation of ore bodies has been of immense importance as a source of copper across much of northern Europe. The Zechstein salt layer is also used for underground gas storage in England, Germany and France. Rotliegend The Rotliegend , Rotliegend Group or Rotliegendes ( German :
255-437: The time near the equator (where high temperatures and arid conditions facilitated evaporation), the sea's inception likely stemmed from a marine transgression rooted in a phase of de-glaciation; the southern portion of Pangaea , the former (and future) Gondwanaland , supported ice sheets in the early Permian. The eventual disappearance of the Zechstein Sea was part of a general marine regression that preceded and accompanied
272-512: The two words are sometimes confused in informal literature. The geological timescale has all systems in the Phanerozoic eonothem subdivided into series. Some of these have their own names; in other cases a system is simply divided into a Lower, Middle and Upper series, with official series being capitalized and unofficial designations (as as "middle Cretaceous") being left uncapitalized. The Cretaceous system is, for example, divided into
289-489: The underlying red ) is a lithostratigraphic unit (a sequence of rock strata ) of latest Carboniferous to Guadalupian (middle Permian ) age that is found in the subsurface of large areas in western and central Europe . The Rotliegend mainly consists of sandstone layers. It is usually covered by the Zechstein and lies on top of regionally different formations of late Carboniferous age. The name Rotliegend has in
#209790