The Thuringian Basin ( German : Thüringer Becken ) is a depression in the central and northwest part of Thuringia in Germany which is crossed by several rivers, the longest of which is the Unstrut . It stretches about 60 kilometres (37 mi) from north to south and around 120 kilometres (75 mi) from east to west. Its height varies from about 150 to 250 m above sea level (NN) .
19-696: The Basin is surrounded by a wide outer girdle of limestone ( Muschelkalk ) ridges (including Hainich , Dün , Hainleite , Hohe Schrecke , Schmücke , Finne ), and to the southwest by the Thuringian Forest and to the southeast by sharply divided terraces (the Ilm-Saale and Ohrdruf Muschelkalk plateaus, and the Saale-Elster Bunter sandstone plateau). The Thuringian Basin belongs to the triassic period, during which horizontal beds of Bunter sandstone , Muschelkalk and Keuper were laid down. Below those lie
38-501: 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 three-part Germanic Trias (that gives the Triassic its name) lying above the older Buntsandstein and below the younger Keuper . The Muschelkalk (" mussel - chalk ") consists of a sequence of limestone and dolomite beds . In
57-808: 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 dolomite ( Zellendolomit ). The Upper Muschelkalk ( Hauptmuschelkalk ) is similar to the Lower Muschelkalk and consists of regular beds of shelly limestone, marl and dolomite. It is divided into six formations: Trochitenkalk , Meißner Formation , Irrel Formation , Gilsdorf Formation and Warburg Formation . The lower portion or Trochitenkalk
76-399: Is from this division that many of the mineral springs of Thuringia and south Germany obtain their saline contents. Subsurface (geology) In geology , bedrock is solid rock that lies under loose material ( regolith ) within the crust of Earth or another terrestrial planet . Bedrock is the solid rock that underlies looser surface material. An exposed portion of bedrock
95-472: Is often called an outcrop . The various kinds of broken and weathered rock material, such as soil and subsoil , that may overlie the bedrock are known as regolith . The surface of the bedrock beneath the soil cover (regolith) is also known as rockhead in engineering geology , and its identification by digging, drilling or geophysical methods is an important task in most civil engineering projects. Superficial deposits can be very thick, such that
114-417: Is often composed entirely of the fragmentary stems of the crinoid Encrinus liliiformis ; higher up come beds with a series of ammonites , Ceratites compressus , 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 . In addition to the fossils mentioned above,
133-711: The Basin and on its perimeter ( Erfurt and the free imperial city of Mühlhausen ). Other towns in the Thuringian Basin are (year of foundation and year of achieving town status in brackets): Large parts of the Basin in the former Thuringian Landgraviate were held by the House of Wettin from 1264 and, after the 1485 Treaty of Leipzig , formed the Thuringian Circle of the Saxon Electorate . Smaller areas used to belong to
152-560: The Ettersberg and Fahnerscher Höhe. The Thuringian Basin is dominated by agriculture. Along with the Magdeburg Börde and Leipzig Bay it is one of the richest arable lands in Germany. It was settled in the 8th and 9th century which makes most of the villages and towns in the basin well over 1000 years old. As a result of the fertile countryside, large cities were established very early on in
171-581: The Saarland and Alsace and northern Eifel , the Lower Muschelkalk has more sandy beds, the Muschelsandstein ., "mussel sandstone" The Middle Muschelkalk or Anbydnite Group consists mainly of evaporites (gypsum, anhydrite and halite ) and is divided into three formations: Karlstadt Formation , Heilbronn Formation and Diemel Formation . The sedimentary facies at the margins of the Germanic Basin
190-764: The Wettin Ernestine duchies and the County of Schwarzburg ; the city of Erfurt was a possession of the Mainz Archbishops . According to the 1815 Congress of Vienna , the Albertine and Mainz lands passed to the Kingdom of Prussia , while the smaller areas on the northern and southern rim formed the Thuringian states . Muschelkalk The Muschelkalk (German for "shell-bearing limestone"; French : calcaire coquillier )
209-433: The bedrock lies hundreds of meters below the surface. Exposed bedrock experiences weathering , which may be physical or chemical, and which alters the structure of the rock to leave it susceptible to erosion . Bedrock may also experience subsurface weathering at its upper boundary, forming saprolite . A geologic map of an area will usually show the distribution of differing bedrock types, rock that would be exposed at
SECTION 10
#1733085745049228-564: The central European Muschelkalk except for similarities in fossil content. Closer at hand, the Alpine Muschelkalk differs in many respects from that of Central Europe, and in its characteristic fossil fauna has a closer affinity with the Triassic Tethys realm . 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 limestones with greenish-grey marls ,
247-526: The following are Muschelkalk forms: Coenothyris vulgaris, Mentzelia mentzeli and Spiriferina hirsuta, Myophoria vulgaris, Rhynchotites hirundo, Ceratites munsteri, Ptychites studeri, Balatonites balatonicus, Aspidura scutellata, Daonella lommeli , and in the Alpine region several rock-forming algae (for example, Baciryllium, Gyroporella, and Diplopora ). The salt beds are worked at Halle (Saale) , Bad Friedrichshall , Heilbronn , Szczecin and Erfurt . It
266-644: The middle group being composed of gypsiferous and saliniferous marls with dolomite. Stylolites 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,
285-455: 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 layers of rock. 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
304-469: The salt and gypsum layers of Magnesian Limestone ( Zechstein ). In the Cenozoic era the surrounding ridges were uplifted, whilst the Thuringian Basin sank to form a saucer-shaped depression. The elevation of the Thuringian Basin descends from the south and west to the east. While some of the marginal ridges have the character of low mountain ranges, there are no really noteworthy uplands within it, apart from
323-408: The 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 , German : Welle the "wave" chalk, so called on account of the buckled wavy character the bedding has received. In
342-703: The unit, namely the frequent occurrence of lenticular banks composed of fossil shells. The Muschelkalk is restricted to the subsurface in most of Germany and adjacent regions as the Low Countries , the North Sea and parts of Silesia , Poland and Denmark . Outcrops are found in Thuringia , the Harz , Franconia , Hesse , Swabia , and the Saarland and in Alsace . The Muschelkalk
361-598: 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 history in common with
#48951