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32-523: 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 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

64-415: A distinct kind of sediment for that area or environment. Since its inception in 1838, the facies concept has been extended to related geological concepts. For example, characteristic associations of organic microfossils, and particulate organic material, in rocks or sediments, are called palynofacies . Discrete seismic units are similarly referred to as seismic facies. Sedimentary facies are described in

96-435: A group of "facies descriptors" which must be distinct, reproducible and exhaustive. A reliable facies description of an outcrop in the field would include: composition, texture, sedimentary structure(s), bedding geometry, nature of bedding contact, fossil content and colour. The sequence of minerals that develop during progressive metamorphism (that is, metamorphism at progressively higher temperatures and/or pressures) define

128-436: A section. The samples are analyzed to determine their detrital remanent magnetism (DRM), that is, the polarity of Earth's magnetic field at the time a stratum was deposited. For sedimentary rocks this is possible because, as they fall through the water column, very fine-grained magnetic minerals (< 17  μm ) behave like tiny compasses , orienting themselves with Earth's magnetic field . Upon burial, that orientation

160-431: Is also commonly used to delineate the nature and extent of hydrocarbon -bearing reservoir rocks, seals, and traps of petroleum geology . Chronostratigraphy is the branch of stratigraphy that places an absolute age, rather than a relative age on rock strata . The branch is concerned with deriving geochronological data for rock units, both directly and inferentially, so that a sequence of time-relative events that created

192-841: 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

224-534: Is due to physical contrasts in rock type ( lithology ). This variation can occur vertically as layering (bedding), or laterally, and reflects changes in environments of deposition (known as facies change). These variations provide a lithostratigraphy or lithologic stratigraphy of the rock unit. Key concepts in stratigraphy involve understanding how certain geometric relationships between rock layers arise and what these geometries imply about their original depositional environment. The basic concept in stratigraphy, called

256-574: Is from this division that many of the mineral springs of Thuringia and south Germany obtain their saline contents. Stratigraphy Stratigraphy is a branch of geology concerned with the study of rock layers ( strata ) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks . Stratigraphy has three related subfields: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy (stratigraphy by age). Catholic priest Nicholas Steno established

288-417: 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,

320-411: Is preserved. For volcanic rocks, magnetic minerals, which form in the melt, orient themselves with the ambient magnetic field, and are fixed in place upon crystallization of the lava. Oriented paleomagnetic core samples are collected in the field; mudstones , siltstones , and very fine-grained sandstones are the preferred lithologies because the magnetic grains are finer and more likely to orient with

352-522: Is the vertical stratigraphic succession that typifies marine transgressions and regressions . Ideally, a sedimentary facies is a distinctive rock unit that forms under certain conditions of sedimentation , reflecting a particular process or environment. Sedimentary facies are either descriptive or interpretative. Sedimentary facies are bodies of sediment that are recognizably distinct from adjacent sediments that resulted from different depositional environments. Generally, geologists distinguish facies by

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384-457: The aspect of the rock or sediment being studied. Facies based on petrological characters (such as grain size and mineralogy ) are called lithofacies , whereas facies based on fossil content are called biofacies . A facies is usually further subdivided. The characteristics of the rock unit come from the depositional environment and from the original composition. Sedimentary facies reflect their depositional environment, each facies being

416-431: The law of superposition , states: in an undeformed stratigraphic sequence, the oldest strata occur at the base of the sequence. Chemostratigraphy studies the changes in the relative proportions of trace elements and isotopes within and between lithologic units. Carbon and oxygen isotope ratios vary with time, and researchers can use those to map subtle changes that occurred in the paleoenvironment. This has led to

448-564: The natural remanent magnetization (NRM) to reveal the DRM. Following statistical analysis, the results are used to generate a local magnetostratigraphic column that can then be compared against the Global Magnetic Polarity Time Scale. This technique is used to date sequences that generally lack fossils or interbedded igneous rocks. The continuous nature of the sampling means that it is also a powerful technique for

480-601: 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

512-615: The ambient field during deposition. If the ancient magnetic field were oriented similar to today's field ( North Magnetic Pole near the North Rotational Pole ), the strata would retain a normal polarity. If the data indicate that the North Magnetic Pole were near the South Rotational Pole , the strata would exhibit reversed polarity. Results of the individual samples are analyzed by removing

544-579: 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 ,

576-464: The changes that may occur in those attributes over a geographic area. A facies encompasses all the characteristics of a rock including its chemical, physical, and biological features that distinguish it from adjacent rock. The term "facies" was introduced by the Swiss geologist Amanz Gressly in 1838 and was part of his significant contribution to the foundations of modern stratigraphy , which replaced

608-505: The earlier notions of Neptunism . Walther's law of facies, or simply Walther's law, named after the geologist Johannes Walther , states that the vertical succession of facies reflects lateral changes in environment. Conversely, it states that when a depositional environment "migrates" laterally, sediments of one depositional environment come to lie on top of another. In Russia the law is known as Golovkinsky-Walther's law, honoring also Nikolai A. Golovkinsky . A classic example of this law

640-458: The estimation of sediment-accumulation rates. Sedimentary facies In geology , a facies ( / ˈ f eɪ ʃ ɪ . iː z / FAY -shih-eez , US also / ˈ f eɪ ʃ iː z / FAY -sheez ; 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 condition of formation) and

672-530: 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

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704-512: The gap may be due to removal by erosion, in which case it may be called a stratigraphic vacuity. It is called a hiatus because deposition was on hold for a period of time. A physical gap may represent both a period of non-deposition and a period of erosion. A geologic fault may cause the appearance of a hiatus. Magnetostratigraphy is a chronostratigraphic technique used to date sedimentary and volcanic sequences. The method works by collecting oriented samples at measured intervals throughout

736-596: 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,

768-437: The rock layers. Strata from widespread locations containing the same fossil fauna and flora are said to be correlatable in time. Biologic stratigraphy was based on William Smith's principle of faunal succession , which predated, and was one of the first and most powerful lines of evidence for, biological evolution . It provides strong evidence for the formation ( speciation ) and extinction of species . The geologic time scale

800-484: The rocks formation can be derived. The ultimate aim of chronostratigraphy is to place dates on the sequence of deposition of all rocks within a geological region, and then to every region, and by extension to provide an entire geologic record of the Earth. A gap or missing strata in the geological record of an area is called a stratigraphic hiatus. This may be the result of a halt in the deposition of sediment. Alternatively,

832-405: The significance of strata or rock layering and the importance of fossil markers for correlating strata; he created the first geologic map of England. Other influential applications of stratigraphy in the early 19th century were by Georges Cuvier and Alexandre Brongniart , who studied the geology of the region around Paris. Variation in rock units, most obviously displayed as visible layering,

864-408: 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

896-406: The specialized field of isotopic stratigraphy. Cyclostratigraphy documents the often cyclic changes in the relative proportions of minerals (particularly carbonates ), grain size, thickness of sediment layers ( varves ) and fossil diversity with time, related to seasonal or longer term changes in palaeoclimates . Biostratigraphy or paleontologic stratigraphy is based on fossil evidence in

928-429: The theoretical basis for stratigraphy when he introduced the law of superposition , the principle of original horizontality and the principle of lateral continuity in a 1669 work on the fossilization of organic remains in layers of sediment. The first practical large-scale application of stratigraphy was by William Smith in the 1790s and early 19th century. Known as the "Father of English geology", Smith recognized

960-733: 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

992-615: 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

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1024-529: Was developed during the 19th century, based on the evidence of biologic stratigraphy and faunal succession. This timescale remained a relative scale until the development of radiometric dating , which was based on an absolute time framework, leading to the development of chronostratigraphy. One important development is the Vail curve , which attempts to define a global historical sea-level curve according to inferences from worldwide stratigraphic patterns. Stratigraphy

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