# Keuper > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Keuper > Markdown URL: https://mediated.wiki/source/Keuper.md > Source: https://en.wikipedia.org/wiki/Keuper > Source revision: 1330604850 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) The **Keuper** is a [lithostratigraphic](/source/Lithostratigraphy) unit (a sequence of [rock strata](/source/Rock_strata)) in the [subsurface](/source/Subsurface_(geology)) of large parts of west and central [Europe](/source/Europe). The Keuper consists of [dolomite](/source/Dolomite_(rock)), [shales](/source/Shale) or [claystones](/source/Claystone) and [evaporites](/source/Evaporite) that were deposited during the [Middle](/source/Middle_Triassic) and [Late Triassic](/source/Late_Triassic) [epochs](/source/Epoch_(reference_date)) (about ). The Keuper lies on top of the [Muschelkalk](/source/Muschelkalk) and under the predominantly [Lower Jurassic](/source/Lower_Jurassic) [Lias](/source/Lias_Group) or other Early Jurassic strata. The Keuper together with the Muschelkalk and the [Buntsandstein](/source/Buntsandstein) form the [Germanic Trias Group](/source/Germanic_Trias), a characteristic sequence of rock strata that gave the [Triassic](/source/Triassic) its name.[1] ## Exposure The Upper Triassic is well exposed in [Swabia](/source/Swabia), [Franconia](/source/Franconia), [Alsace](/source/Alsace) and [Lorraine](/source/Lorraine_(region)) and [Luxembourg](/source/Luxembourg); it extends from [Basel](/source/Basel) on the east side of the [Rhine](/source/Rhine) into [Hanover](/source/Hanover), and through [England](/source/England) into [Scotland](/source/Scotland) and north-east [Ireland](/source/Ireland); it appears flanking the central plateau of [France](/source/France) and in the [Pyrenees](/source/Pyrenees) and [Sardinia](/source/Sardinia).[2] The Keuper sequence is linked by name to the [Keuper Uplands](/source/Keuper_Uplands) area of southern Germany. In south [Sweden](/source/Sweden), the lower portion contains [coal](/source/Coal)-bearing strata, as in the [Himalayas](/source/Himalayas), [Japan](/source/Japan), [Tibet](/source/Tibet), [Burma](/source/Burma), eastern [Siberia](/source/Siberia) and in [Spitsbergen](/source/Spitsbergen). The upper portion of the [Karoo Supergroup](/source/Karoo_Supergroup) of [South Africa](/source/South_Africa) and part of the [Otapiri stage](/source/Otapiri_stage) of [New Zealand](/source/New_Zealand) are probably of Rhaetian age.[2] ### Germany In Germany and adjacent parts of western and central Europe, the Keuper unit is divided into three groups: - **[Upper Keuper](/source/Upper_Keuper)** - The upper part of this division is often a grey [dolomite](/source/Dolomite_(rock)) known as the [Grenz dolomite](/source/Grenz_dolomit); the impure [coal](/source/Coal) beds Lettenkohle are aggregated towards the base. The upper Keuper, Rhaetic or Avicula contorta zone in Germany is mainly sandy with dark grey [shales](/source/Shale) and [marls](/source/Marl); it is seldom more than 25 m (82 ft). The sandstones are used for building purposes at [Bayreuth](/source/Bayreuth), Culmbach and [Bamberg](/source/Bamberg). In Swabia and the Wesergebirge are several [bone](/source/Bone)-beds, thicker than those in the middle Keuper, which contain a rich assemblage of fossil remains of fish, reptiles and the mammalian teeth of *[Microlestes antiquus](/source/Microlestes_antiquus)* and *Triglyptzas Fraasi*. The name "Rhaetic" is derived from the Rhaetic Alps where the beds are well developed; they occur also in central France, the Pyrenees and England. In South Tirol and the Judicarian Mountains, the Rhaetic is represented by the [Kossenei](/source/Kossenei) beds. In the Alpine region, the presence of coral beds gives rise to the so-called Lithodendron Kalk.[2] - ***[Hauptkeuper](/source/Hauptkeuper)*** or *Gipskeuper*, the middle - The middle division is thicker than either of the others (at Göttingen, 450 m (1,480 ft)); it consists of a marly series below, grey, red and green marls, with [gypsum](/source/Gypsum) and dolomite—this is the gypskeuper in its restricted sense. The higher part of the series is [sandy](/source/Sand), hence called the Steinmergel; it is comparatively free from gypsum. To this division belong the [Myophoria](/source/Myophoria) beds ([M. Raibliana](/source/M._Raibliana)) with [galena](/source/Galena) in places; the [Estheria](/source/Lioestheria) beds ([E. laxilesta](/source/E._laxilesta)); the Schelfsandstein, used as a building-stone; the [Lehrherg](/source/Lehrherg) and [Berg-gyps](/source/Berg-gyp) beds; [Semionotus](/source/Semionotus) beds ([S. Bergen](/source/S._Bergen)) with building-stone of [Coburg](/source/Coburg); and the Burgand [Stubensandstein](/source/Stubensandstein).[2] - ***[Kohlenkeuper](/source/Kohlenkeuper), Unterkeuper*** or *Lettenkohle*, the lower - The lower division consists mainly of grey [clays](/source/Clay) and [schieferletten](/source/Schieferletten) with white, grey and brightly colored [sandstone](/source/Sandstone) and dolomitic [limestone](/source/Limestone).[2] The [salt](/source/Salt), which is associated with gypsum, is exploited in south Germany at Dreuze, Pettoncourt, as well as in Vie in the [Lorraine](/source/Lorraine_(region)) region of France. A 4-metre (13 ft) coal is found on this horizon in the [Ore Mountains](/source/Ore_Mountains) on the border between Germany and the [Czech Republic](/source/Czech_Republic), and another, 2 metres thick (7 ft), has been mined in [Upper Silesia](/source/Upper_Silesia), now in [Poland](/source/Poland).[2] ### Great Britain In Great Britain the 'Keuper' is no longer a formally recognised geological division. The one-time Keuper Marls are now redesignated as the [Mercia Mudstone Group](/source/Mercia_Mudstone_Group). The underlying Keuper Sandstone is now the Helsby Sandstone Formation at the top of the [Sherwood Sandstone Group](/source/Sherwood_Sandstone_Group). Traditionally it contained the following subdivisions: - **[Rhaetic or Penarth](/source/Penarth_Group)** - Grey, red and green marls, black shales, and so-called white (10–150 ft (3.0–45.7 m)). Upper Keuper marl, red and grey marls and shales with rock salt, 240–910 m (800–3,000 ft). As in Germany, there are one or more bone beds in the English Rhaetic with a similar assemblage of fossils. - **[Lower Keuper](/source/Lower_Keuper)** - Sandstone, marls and thin sandstones at the top, red and white sandstones (including the so-called waterstones) below, with [breccias](/source/Breccia) and conglomerates at the base, 46–76 m (150–250 ft). - **Basal conglomerate** - A shore or scree breccia derived from local materials; it is well developed in the [Mendip](/source/Mendip_District) district. The rocksalt beds vary from 25 cm (1 inch) to 30 m (100 feet) in thickness; they are extensively worked (mined and pumped) in [Cheshire](/source/Cheshire), [Middlesbrough](/source/Middlesbrough) and [County Antrim](/source/County_Antrim).[2] The Keuper covers a large area in the [Midlands](/source/English_Midlands) and around the flanks of the [Pennine](/source/Pennines) range; it reaches southward to the east [Devon](/source/Devon) coast, northeastward into [Yorkshire](/source/Yorkshire) and northwestward into Northern Ireland and southernmost Scotland.[2] ## Fossils The Keuper is not rich in [fossils](/source/Fossil); the principal plants are [cypresslike](/source/Cupressaceae) [conifers](/source/Conifer) (*[Walchia](/source/Walchia)*, *[Voltzia](/source/Voltziales)*) and a few [calamites](/source/Calamites) with such forms as *Equisetum arenaceum* and *Pterophyllum jaegeri*. *Avicula contorta*, *Protocardium rhaeticum*, *[Terebratula](/source/Terebratula) gregaria*, *Myophoria costata*, *M. goldfassi*, *[Lingula tenuessima](/source/Lingula_tenuessima)*, and *Anoplophoria lettica* may be mentioned among the invertebrates. The fish include *[Ceratodus](/source/Ceratodus_(genus))*, *[Hybodus](/source/Hybodus)* and *[Lepidotus](/source/Lepidotus)*.[2] [Labyrinthodonts](/source/Labyrinthodont) represented by the footprints of *Cheirotherium* and the bones of *[Mastodonsaurus](/source/Mastodonsaurus)* (originally called *Labyrinthodon*) and *[Capitosaurus](/source/Capitosaurus)*. Among the [reptiles](/source/Reptile) are *[Hyperodapedon](/source/Hyperodapedon)*, *[Palaeosaurus](/source/Palaeosaurus)*, *[Zanclodon](/source/Zanclodon)*, *[Nothosaurus](/source/Nothosaurus)*, *[Henodus](/source/Henodus)* and *[Belodon](/source/Belodon)*.[2] The first fossil [mammals](/source/Mammal) also make their appearance at this time and the early [beetle](/source/Beetle) *[Triamyxa](/source/Triamyxa)* is also known from the Keuper. ## Notes 1. "Muschelkalk (geology)", [Britannica Online Encyclopedia](/source/Britannica_Online_Encyclopedia), October 2010, webpage: [EB-39](http://www.britannica.com/EBchecked/topic/398539/Muschelkalk). 1. Howe 1911. ## References - Ogg, James G.; Ogg, Gabi M.; Gradstein, Felix M. (2016). "Triassic". *A Concise Geologic Time Scale: 2016*. Elsevier. pp. 133–149. ISBN 978-0-444-63771-0. --- Adapted from the Wikipedia article [Keuper](https://en.wikipedia.org/wiki/Keuper) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Keuper?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.