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The Muschelkalk
Muschelkalk
(German: shellbearing limestone, French: calcaire coquillier) is a sequence of sedimentary rock strata (a lithostratigraphic unit) in the geology of central and western Europe. It has a Middle Triassic
Triassic
(240 to 230 million years) age and forms the middle part of the tripartite Germanic Trias, that give the Triassic its name, lying above the older Buntsandstein
Buntsandstein
and below the younger Keuper. The Muschelkalk
Muschelkalk
("mussel chalk") consists of a sequence of limestone and dolostone beds. In the past, the time span in which the Muschelkalk
Muschelkalk
was deposited could also be called "Muschelkalk". In modern stratigraphy, however, the name only applies to the stratigraphic unit.

Contents

1 Occurrence 2 Stratigraphy

2.1 Germany

3 Fossil
Fossil
content 4 Exploration 5 References

Occurrence[edit]

An outcrop of Muschelkalk
Muschelkalk
cliffs forms the shore of the Wutach River, in the south of Baden-Württemberg.

The name Muschelkalk
Muschelkalk
was first used by German geologist Georg Christian Füchsel (1722-1773). In 1834, Friedrich August von Alberti included it into the Triassic
Triassic
system. The name indicates a characteristic feature of the unit, namely the frequent occurrence of lenticular banks composed of fossil shells. The Muschelkalk
Muschelkalk
is restricted to the subsurface in most of Germany and adjacent regions as the low countries, the North Sea
North Sea
and parts of Silesia, Poland
Poland
and Denmark. Outcrops are found in Thuringia, the Harz, Franconia, Hesse, Swabia, and the Saarland
Saarland
and in Alsace. The Muschelkalk
Muschelkalk
was deposited in a land-locked sea which, in the earlier part of its existence, had only imperfect communications with the more open waters of the Tethys Ocean
Tethys Ocean
to the south. The basin in which the Muschelkalk
Muschelkalk
was deposited is called the Germanic Basin. Sometimes stratigraphic units with the same age from the Alps, southern Europe and even Asia
Asia
are called Muschelkalk
Muschelkalk
too. Of course these rocks have little history in common with the central European Muschelkalk
Muschelkalk
except for similarities in fossil content. Closer at hand, the Alpine Muschelkalk
Muschelkalk
differs in many respects from that of Central Europe, and in its characteristic fossil fauna has a closer affinity with the Triassic
Triassic
Tethys realm. Stratigraphy[edit] The Muschelkalk
Muschelkalk
can be up to 100 meters thick; it is divisible into three subdivisions, of which the upper and lower are pale thin-bedded limestones with greenish-grey marls, the middle group being composed of gypsiferous and saliniferous marls with dolostone. Stylolites are common in all the Muschelkalk
Muschelkalk
limestones. The lithostratigraphic status of the Muschelkalk
Muschelkalk
differs regionally. In Germany it is considered a group, in the Netherlands
Netherlands
a formation. Germany[edit]

The top of the hard limestone (Schaumkalk) bed forms the top of the Wellenkalk or Lower Muschelkalk
Muschelkalk
and the base of the Orbicularismergel, part of the Karlstadt-Formation. Outcrop
Outcrop
near Dörzbach, Baden-Württemberg.

Fossils of Encrinus
Encrinus
liliiforrnis from the Upper Muschelkalk
Muschelkalk
at Kirchberg an der Jagst, Baden-Württemberg. Field of view approximately 20mm

The German Muschelkalk
Muschelkalk
Group is subdivided into three subgroups: Upper, Middle and Lower Muschelkalk. The Lower Muschelkalk
Muschelkalk
consists mainly of limestone, calcareous marls and clayey marls. Some beds are composed of porous cellular limestone, the so-called Schaumkalk, there are also oolite beds. The Lower Muschelkalk
Muschelkalk
is divided into six formations: Jena Formation, Rüdersdorf Formation, Udelfangen Formation, Freudenstadt Formation and Eschenbach Formation. The Lower Muschelkalk
Muschelkalk
is sometimes called Wellenkalk, German: Welle the "wave" chalk, so called on account of the buckled wavy character the bedding has received. In the Saarland
Saarland
and Alsace
Alsace
and northern Eifel, the Lower Muschelkalk
Muschelkalk
has more sandy beds, the Muschelsandstein., "mussel sandstone" The Middle Muschelkalk
Muschelkalk
or Anbydnite Group consists mainly of evaporites (gypsum, anhydrite and halite) and is divided into three formations: Karlstadt Formation, Heilbronn
Heilbronn
Formation and Diemel Formation. The sedimentary facies at the margins of the Germanic Basin is different and these deposits are classified as a separate formation, the Grafenwöhr Formation, which continues into the Upper Muschelkalk. In the Middle Muschelkalk, weathering can form characteristic cellular dolostone (Zellendolomit). The Upper Muschelkalk
Muschelkalk
(Hauptmuschelkalk) is similar to the Lower Muschelkalk
Muschelkalk
and consists of regular beds of shelly limestone, marl and dolostone. It is divided into six formations: Trochitenkalk, Meißner Formation, Irrel Formation, Gilsdorf Formation and Warburg Formation. The lower portion or Trochitenkalk is often composed entirely of the fragmentary stems of the crinoid Encrinus
Encrinus
liliiformis; higher up come beds with a series of ammonites, Ceratites
Ceratites
cornpressus, Ceratites nodosus, and Ceratites
Ceratites
semipartitus in ascending order. In Swabia
Swabia
and Franconia
Franconia
the highest beds are platy dolomites with Tringonodus sandergensis and the crustacean Bairdia. Fossil
Fossil
content[edit] In addition to the fossils mentioned above, the following are Muschelkalk
Muschelkalk
forms: Terebratulina vulgaris, Spiriferina Mantzeln and S. hirsute, Myophoria vulgaris, Rhynchotites hirundo, Ceratites
Ceratites
Munsteri, Ptychites studeri, Balatonites balatonicus, Aspidura scutellate, Daonella
Daonella
Lommeli, and in the Alpine region several rock-forming Algae, Baciryllium, Gyroporella, Diptopora, etc. Exploration[edit] The salt beds are worked at Hall, Friedrichshall, Heilbronn, Szczecin and Erfurt. It is from this division that many of the mineral springs of Thuringia
Thuringia
and south Germany obtain their saline contents. References[edit]

 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Muschelkalk". Encyclopædia Britannica (11th ed.). Cambridge University Press. 

^ Gradstein, F.M.; Ogg, J.G.; Smith, A.G. (2005), A Geologic Time Scale 2004, Cambridge University Press, ISBN 9780521786737 

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