Germanic Trias
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The Germanic Trias Supergroup () is a
lithostratigraphic Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology. In general, strata are primarily igneous ...
unit (a sequence of
rock strata In geology and related fields, a stratum (: strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ...
) in the subsurface of large parts of western and central
Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
(north of the
Alps The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia. ...
) and the
North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...
. Almost all of the Germanic Trias was deposited during the
Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...
period and consists of three clearly different units:
Buntsandstein The Buntsandstein (German for ''coloured'' or ''colourful sandstone'') or Bunter sandstone is a lithostratigraphy, lithostratigraphic and allostratigraphy, allostratigraphic unit (a sequence of rock strata) in the Subsurface (geology), subsurface ...
,
Muschelkalk The Muschelkalk (German for "shell-bearing limestone"; ) is a sequence of sedimentary rock, sedimentary rock strata (a lithostratigraphy, lithostratigraphic unit) in the geology of central and western Europe. It has a Middle Triassic (240 to 230 m ...
and
Keuper The Keuper is a lithostratigraphic unit (a sequence of rock strata) in the subsurface of large parts of west and central Europe. The Keuper consists of dolomite, shales or claystones and evaporites that were deposited during the Middle and Lat ...
, that gave the period its name (''Triassic'' means "threefold"). In the past the names of these three units were also used as units in the
geologic timescale The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochron ...
, but in modern literature they only have a lithostratigraphic meaning.


Origin

The Germanic Trias formed in the large Germanic Basin, a basin that covered much of midwestern Europe (including the south of the North Sea and
Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...
) during the Triassic. The Muschelkalk has a predominantly marine
facies In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with distinctive characteristics. The characteristics can be any observable attribute of rocks (such as their overall appearance, composition, or con ...
whereas the Buntsandstein and Keuper are mostly
continent A continent is any of several large geographical regions. Continents are generally identified by convention (norm), convention rather than any strict criteria. A continent could be a single large landmass, a part of a very large landmass, as ...
al.


Stratigraphy

In the central parts of the Germanic Basin, the Germanic Trias has an average thickness of 800 meters, but regional differences are considerable. In the north of Germany the thickness of the Buntsandstein alone can exceed 1400 meters. The Germanic Trias lies on top of the
Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...
Zechstein Group 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 ...
and below
Lower Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic–Jurassic extinction event, 201.3 Ma&nb ...
units, such as the
Lias Group The Lias Group or Lias is a lithostratigraphic unit (a sequence of rock strata) found in a large area of western Europe, including the British Isles, the North Sea, the Low Countries and the north of Germany. It consists of marine limestones, ...
or Altena Group. The base is not defined in the same way everywhere. In northern Germany the base is formed by the Calvörde Beds, in the
Spessart Spessart () is a ''Mittelgebirge'', a range of low wooded mountains, in the States of Bavaria and Hesse in Germany. It is bordered by the Vogelsberg, Rhön and Odenwald. The highest elevation is the Geiersberg (Spessart), Geiersberg at 586 metre ...
and
Odenwald The Odenwald () is a low mountain range in the Germany, German states of Hesse, Bavaria and Baden-Württemberg. Location The Odenwald is located between the Upper Rhine Plain with the Bergstraße Route, Bergstraße and the ''Hessisches Ried' ...
by the base of the Heigenbrücken-Sandstone.
Radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to Chronological dating, date materials such as Rock (geology), rocks or carbon, in which trace radioactive impurity, impurities were selectively incorporat ...
has shown the age of the Germanic Trias is not totally corresponding with the Triassic period. The base of the Buntsandstein was formed during the
Changhsingian In the geologic time scale, the Changhsingian or Changxingian is the latest age or uppermost stage of the Permian. It is also the upper or latest of two subdivisions of the Lopingian Epoch or Series. The Changhsingian lasted from to 251.9 Ma a ...
, the uppermost
stage Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...
of the Permian, about . The top of the Keuper is
Rhaetian The Rhaetian is the latest age (geology), age of the Triassic period (geology), Period (in geochronology) or the uppermost stage (stratigraphy), stage of the Triassic system (stratigraphy), System (in chronostratigraphy). It was preceded by the N ...
in age and at about at least a few million years older than the Triassic-Jurassic boundary. Usually there is a stratigraphic hiatus between the base of the Lias and top of the Germanic Trias. In German lithostratigraphy, Buntsandstein, Muschelkalk and Keuper are seen as groups. Dutch lithostratigraphy divides the Germanic Trias along other boundaries in a Lower Germanic Trias Group and an Upper Germanic Trias Group. The Dutch Keuper and Muschelkalk have the status of formations while the Dutch Buntsandstein is subdivided in a number of formations. The Bunter of British stratigraphy is similar in age,
lithology The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lit ...
and facies to the Buntsandstein.


See also

* Geology of Germany


References

{{Authority control Permian Europe Triassic Europe Geology of Germany Lithostratigraphy of Germany North Sea