Muschelkalk
Encyclopedia
The Muschelkalk is a sequence of sedimentary
rock strata (a lithostratigraphic unit
) in the geology
of central and western Europe. It has a Middle Triassic
(240 to 230 million years) age and forms the middle part of the Germanic Trias
, that further consists of the Buntsandstein
(lower part) and Keuper
(upper part). The Muschelkalk consists of a sequence of limestone
and dolostone
beds.
In the past the time span in which the Muschelkalk was deposited could also be called Muschelkalk. In modern stratigraphy however, the name only applies to the stratigraphic unit.
The name Muschelkalk was first used by German geologist Georg Christian Füchsel (1722-1773). In 1834, Friedrich August von Alberti
included it into the Triassic system. The name indicates a characteristic feature of the unit, namely the frequent occurrence of lenticular banks composed of fossil
shells. The Muschelkalk is restricted to the subsurface
of Germany and adjacent regions as the low countries
, the North Sea
and parts of Silesia
, Poland
and Denmark
. Outcrop
s are found in Thuringia
, the Harz
, Franconia
, Hesse
, Swabia
, and the Saarland
and the Alsace
.
The 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
to the south. The basin
in which the Muschelkalk was deposited is called the Germanic Basin.
Sometimes stratigraphic units with the same age from the Alps
, southern Europe and even Asia
are called Muschelkalk too. Of course these rocks have little in common with the central European Muschelkalk except for similarities in fossil content. The Alpine Muschelkalk differs in many respects from that of Central Europe, and has a closer affinity with the Triassic Tethys realm.
s with greenish-grey marl
s, the middle group being composed of gypsiferous
and saliniferous marls with dolostone. Stylolite
s are common in all the Muschelkalk limestones.
The lithostratigraphic status of the Muschelkalk differs regionally. In Germany it is considered a group
, in the Netherlands
a formation
.
The German Muschelkalk Group is subdivided into three subgroups: Upper, Middle and Lower Muschelkalk. The Lower Muschelkalk consists mainly of limestone, calcareous marls and clayey marls. Some beds are composed of porous cellular limestone occur (so called Schaumkalk), there are also oolite
beds. The Lower Muschelkalk is divided into six formations: Jena-Formation, Rüdersdorf-Formation, Udelfangen-Formation, Freudenstadt-Formation and Eschenbach-Formation. The Lower Muschelkalk is sometimes called Wellenkalk ( = wave, so called on account of the wavy
character of the bedding
). In the Saarland and Alsace and northern Eifel
, the Lower Muschelkalk has more sandy beds, the Muschelsandstein.
The Middle Muschelkalk or Anbydnite Group consists mainly of evaporite
s (gypsum, anhydrite
and halite
) and is divided into three formations: Karlstadt-Formation, Heilbronn-Formation and Diemel-Formation. The 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 (Hauptmuschelkalk) is similar to the Lower 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 Encrinus liliiforrnis; higher up come beds with Ceratites cornpressus, Ceratites nodosus, and Ceratites semipartitus in ascending order. In Swabia and Franconia the highest beds are platy dolomites with Tringonodus sandergensis and the crustacean
Bairdia.
, Baciryllium, Gyroporella, Diptopora, etc.
, Friedrichshall, Heilbronn
, Szczecin
and Erfurt
. It is from this division that many of the mineral springs of Thuringia
and south Germany obtain their saline contents.
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
rock strata (a lithostratigraphic unit
Lithostratigraphy
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 the geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
of central and western Europe. It has a Middle Triassic
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided. It spans the time between 245 ± 1.5 Ma and 228 ± 2 Ma...
(240 to 230 million years) age and forms the middle part of the Germanic Trias
Germanic Trias
The Germanic Trias Supergroup is a lithostratigraphic unit in the subsurface of large parts of western and central Europe and the North Sea...
, that further consists of the Buntsandstein
Buntsandstein
The Buntsandstein or Bunter sandstone is a lithostratigraphic and allostratigraphic unit in the subsurface of large parts of west and central Europe...
(lower part) and Keuper
Keuper
The Keuper is a lithostratigraphic unit in the subsurface of large parts of west and central Europe. The Keuper consists of dolostone, shales or claystones and evaporites that were deposited during the Middle and Late Triassic epochs...
(upper part). The Muschelkalk consists of a sequence of limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
and dolostone
Dolostone
Dolostone or dolomite rock is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite. In old U.S.G.S. publications it was referred to as magnesian limestone. Most dolostone formed as a magnesium replacement of limestone or lime mud prior to lithification. It is...
beds.
In the past the time span in which the Muschelkalk was deposited could also be called Muschelkalk. In modern stratigraphy however, the name only applies to the stratigraphic unit.
Occurrence
Friedrich August von Alberti
Dr. Friedrich August von Alberti was a German geologist whose ground-breaking 1834 publication recognized the unity of the three characteristic strata that compose the sedimentary deposits of the Triassic period in Northern Europe...
included it into the Triassic system. The name indicates a characteristic feature of the unit, namely the frequent occurrence of lenticular banks composed of fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
shells. The Muschelkalk is restricted to the subsurface
Subsurface
Subsurface is the seventh studio album by British progressive metal band Threshold. The album was released in August 2004, and received an Album of the Month award in several European music magazines....
of Germany and adjacent regions as the low countries
Low Countries
The Low Countries are the historical lands around the low-lying delta of the Rhine, Scheldt, and Meuse rivers, including the modern countries of Belgium, the Netherlands, Luxembourg and parts of northern France and western Germany....
, the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
and parts of Silesia
Silesia
Silesia is a historical region of Central Europe located mostly in Poland, with smaller parts also in the Czech Republic, and Germany.Silesia is rich in mineral and natural resources, and includes several important industrial areas. Silesia's largest city and historical capital is Wrocław...
, Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
and Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
. Outcrop
Outcrop
An outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. -Features:Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by a mantle of soil and vegetation and cannot be...
s are found in Thuringia
Thuringia
The Free State of Thuringia is a state of Germany, located in the central part of the country.It has an area of and 2.29 million inhabitants, making it the sixth smallest by area and the fifth smallest by population of Germany's sixteen states....
, the Harz
Harz
The Harz is the highest mountain range in northern Germany and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt and Thuringia. The name Harz derives from the Middle High German word Hardt or Hart , latinized as Hercynia. The legendary Brocken is the highest summit in the Harz...
, Franconia
Franconia
Franconia is a region of Germany comprising the northern parts of the modern state of Bavaria, a small part of southern Thuringia, and a region in northeastern Baden-Württemberg called Tauberfranken...
, Hesse
Hesse
Hesse or Hessia is both a cultural region of Germany and the name of an individual German state.* The cultural region of Hesse includes both the State of Hesse and the area known as Rhenish Hesse in the neighbouring Rhineland-Palatinate state...
, Swabia
Swabia
Swabia is a cultural, historic and linguistic region in southwestern Germany.-Geography:Like many cultural regions of Europe, Swabia's borders are not clearly defined...
, and the Saarland
Saarland
Saarland is one of the sixteen states of Germany. The capital is Saarbrücken. It has an area of 2570 km² and 1,045,000 inhabitants. In both area and population, it is the smallest state in Germany other than the city-states...
and the Alsace
Alsace
Alsace is the fifth-smallest of the 27 regions of France in land area , and the smallest in metropolitan France. It is also the seventh-most densely populated region in France and third most densely populated region in metropolitan France, with ca. 220 inhabitants per km²...
.
The 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
The Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean.-Modern theory:...
to the south. The basin
Basin (geology)
A structural basin is a large-scale structural formation of rock strata formed by tectonic warping of previously flat lying strata. Structural basins are geological depressions, and are the inverse of domes. Some elongated structural basins are also known as synclines...
in which the Muschelkalk was deposited is called the Germanic Basin.
Sometimes stratigraphic units with the same age from the Alps
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
, southern Europe and even Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
are called Muschelkalk too. Of course these rocks have little in common with the central European Muschelkalk except for similarities in fossil content. The Alpine Muschelkalk differs in many respects from that of Central Europe, and has a closer affinity with the Triassic Tethys realm.
Stratigraphy
The Muschelkalk can be up to 100 meters thick; it is divisible into three subdivisions, of which the upper and lower are pale thin-bedded limestoneLimestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
s with greenish-grey marl
Marl
Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and aragonite. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay...
s, the middle group being composed of gypsiferous
Gypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
and saliniferous marls with dolostone. Stylolite
Stylolite
Stylolites are serrated surfaces at which mineral material has been removed by pressure dissolution, in a process that decreases the total volume of rock. Insoluble minerals like clays, pyrite, oxides remain within the stylolites and make them visible...
s are common in all the Muschelkalk limestones.
The lithostratigraphic status of the Muschelkalk differs regionally. In Germany it is considered a group
Group (stratigraphy)
A group in stratigraphy is a lithostratigraphic unit, a part of the geologic record or rock column that consists of defined rock strata. Groups are divided into formations and are sometimes themselves grouped into "supergroups"....
, in the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
a formation
Formation
Formation may refer to:* Formation flying, aerobatics performed with several aircraft* Formation , a high-level military organization* Tactical formation, the physical deployment of military forces-Sports:...
.
Germany
Oolite
Oolite is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Hellenic word òoion for egg. Strictly, oolites consist of ooids of diameter 0.25–2 mm; rocks composed of ooids larger than 2 mm are called pisolites...
beds. The Lower Muschelkalk is divided into six formations: Jena-Formation, Rüdersdorf-Formation, Udelfangen-Formation, Freudenstadt-Formation and Eschenbach-Formation. The Lower Muschelkalk is sometimes called Wellenkalk ( = wave, so called on account of the wavy
Wave
In physics, a wave is a disturbance that travels through space and time, accompanied by the transfer of energy.Waves travel and the wave motion transfers energy from one point to another, often with no permanent displacement of the particles of the medium—that is, with little or no associated mass...
character of the bedding
Bedding
Bedding refers to the materials laid above the mattress of a bed for hygiene, warmth, to protect the mattress, and for decorative effect. Bedding is the removable and washable portion of a human sleeping environment. It is more easily and economically replaced than the bed itself...
). In the Saarland and Alsace and northern Eifel
Eifel
The Eifel is a low mountain range in western Germany and eastern Belgium. It occupies parts of southwestern North Rhine-Westphalia, northwestern Rhineland-Palatinate and the south of the German-speaking Community of Belgium....
, the Lower Muschelkalk has more sandy beds, the Muschelsandstein.
The Middle Muschelkalk or Anbydnite Group consists mainly of evaporite
Evaporite
Evaporite is a name for a water-soluble mineral sediment that result from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporate deposits, marine which can also be described as ocean deposits, and non-marine which are found in standing bodies of...
s (gypsum, anhydrite
Anhydrite
Anhydrite is a mineral – anhydrous calcium sulfate, CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium and strontium sulfates, as might be expected from the...
and halite
Halite
Halite , commonly known as rock salt, is the mineral form of sodium chloride . Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount and type of impurities...
) and is divided into three formations: Karlstadt-Formation, Heilbronn-Formation and Diemel-Formation. The 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 (Hauptmuschelkalk) is similar to the Lower Muschelkalk and consists of regular beds of shelly limestone, marl and dolostone
Dolostone
Dolostone or dolomite rock is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite. In old U.S.G.S. publications it was referred to as magnesian limestone. Most dolostone formed as a magnesium replacement of limestone or lime mud prior to lithification. It is...
. 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 Encrinus liliiforrnis; higher up come beds with Ceratites cornpressus, Ceratites nodosus, and Ceratites semipartitus in ascending order. In Swabia and Franconia the highest beds are platy dolomites with Tringonodus sandergensis and the crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
Bairdia.
Fossil content
In addition to the fossils mentioned above, the following are Muschelkalk forms: Terebratulina vulgaris, Spiriferina Mantzeln and S. hirsute, Myophoria vulgaris, Rhynchotites hirundo, Ceratites Munsteri, Ptychites studeri, Balatonites balatonicus, Aspidura scutellate, Daonella Lommeli, and in the Alpine region several rock-forming AlgaeAlgae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, Baciryllium, Gyroporella, Diptopora, etc.
Exploration
The salt beds are worked at HallHall
In architecture, a hall is fundamentally a relatively large space enclosed by a roof and walls. In the Iron Age, a mead hall was such a simple building and was the residence of a lord and his retainers...
, Friedrichshall, Heilbronn
Heilbronn
Heilbronn is a city in northern Baden-Württemberg, Germany. It is completely surrounded by Heilbronn County and with approximately 123.000 residents, it is the sixth-largest city in the state....
, Szczecin
Szczecin
Szczecin , is the capital city of the West Pomeranian Voivodeship in Poland. It is the country's seventh-largest city and the largest seaport in Poland on the Baltic Sea. As of June 2009 the population was 406,427....
and Erfurt
Erfurt
Erfurt is the capital city of Thuringia and the main city nearest to the geographical centre of Germany, located 100 km SW of Leipzig, 150 km N of Nuremberg and 180 km SE of Hannover. Erfurt Airport can be reached by plane via Munich. It lies in the southern part of the Thuringian...
. It is from this division that many of the mineral springs of Thuringia
Thuringia
The Free State of Thuringia is a state of Germany, located in the central part of the country.It has an area of and 2.29 million inhabitants, making it the sixth smallest by area and the fifth smallest by population of Germany's sixteen states....
and south Germany obtain their saline contents.