{{Short description|Geological formation preserving rare fossils in Germany}} {{Infobox rockunit | name = Altmühltal Formation | image = Solnhofen - cantera de calizas tableadas.jpg | caption = Outcrop of the Solnhofen Limestone | type = [[Geological formation]] | age = {{fossilrange|Tithonian}}<ref name=rhyncho2012/><ref name="ammonitedate">Schweigert, G. 2007. Ammonite biostratigraphy as a tool for dating Upper Jurassic lithographic limestones from South Germany – first results and open questions." ''Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen'', '''245'''(1): 117–125. {{doi|10.1127/0077-7749/2007/0245-0117}}</ref> | period = Tithonian | prilithology = [[Lithographic limestone]]<ref name=rhyncho2012>Rauhut, O. W., Heyng, A. M., López-Arbarello, A., & Hecker, A. (2012). A new rhynchocephalian from the Late Jurassic of Germany with a dentition that is unique amongst tetrapods. ''PLoS ONE'', 7(10): e46839.</ref> | otherlithology = | namedfor = [[Solnhofen]] | namedby = | region = [[Bavaria]] | country = [[Germany]] | coordinates = {{coord|48.9000|N|11.0000|E|source:wikidata|display=inline,title}} | paleocoordinates = {{coord|40.1|N|19.2|E|display=inline}} | unitof = | subunits = | underlies = [[Mörnsheim Formation]]<ref name=rhyncho2012/> | overlies = [[Rögling Formation]]<ref name=rhyncho2012/> | thickness = | extent = | area = | map = {{Location map+ | Germany#Bavaria | relief = 1 | width = 250 | float = center | places = {{Location map~ | Germany#Bavaria | lat_deg = 48.9 | lon_deg = 11.0 | mark = Cyan pog.svg | marksize = 12 }} }} | map_caption = }} The '''Solnhofen Limestone''' or '''Solnhofen Plattenkalk''', formally known as the '''Altmühltal Formation''', is a [[Jurassic]] [[lagerstätte|Konservat-Lagerstätte]] that preserves a rare assemblage of [[fossil]]ized organisms, including highly detailed imprints of soft bodied organisms such as sea jellies. The most familiar fossils of the Solnhofen Plattenkalk include the early feathered [[theropod]] dinosaur ''[[Archaeopteryx]]'' preserved in such detail that they are among the most famous and most beautiful fossils in the world. The Solnhofen beds lie in the [[Germany|German]] state of [[Bavaria|Bavaria (Bayern)]], halfway between [[Nuremberg|Nuremberg (Nürnberg)]] and [[Munich|Munich (München)]] and were originally quarried as a source of [[lithographic limestone]]. The [[Jura Museum]] situated in [[Eichstätt]], Germany has an extensive exhibit of [[Jurassic]] fossils from the quarries of Solnhofen and surroundings, including marine reptiles, [[pterosaur]]s, and one specimen of the early bird ''[[Archaeopteryx]]''.<ref>{{cite web |title=Jura-Museum Eichstätt | url = http://an01118.hp.altmuehlnet.de/index.php/en/}}</ref>
== Paleoenvironment and preservation == [[File:Brittle star-fossil.jpg|thumb|right|A brittle star fossil from the Solnhofen Limestone]] During the [[Late Jurassic]], this area was an [[archipelago]] at the edge of the [[Tethys Sea]]. This included placid lagoons that had limited access to the open sea and where salinity rose high enough that the resulting brine could not support life. Since the lowest water was devoid of [[oxygen]], many ordinary scavengers were absent. Any organism that fell, drifted, or was washed into the lagoons from the ocean or the land became buried in soft [[carbonate]] mud. Thus, many delicate creatures avoided consumption by scavengers or being torn apart by currents. The wings of [[Dragonfly|dragonflies]], the imprints of stray [[feather]]s, and terrestrial plants that washed into the lagoons were all preserved. The fossils are not numerous, but some of them are spectacular, and their range gives a comprehensive picture of a local Jurassic [[ecosystem]].
At times, the lagoons almost dried out, exposing sticky carbonate muds that trapped insects and a few small [[dinosaur]]s. Over 600 species have been identified, including twenty-nine kinds of [[pterosaur]] ranging from the size of a [[Old World sparrow|sparrow]] to 1.2 m (4 ft) in length.
The fine-grained texture of the mud [[silt]] forming the [[limestone]] from the [[Solnhofen]] area (which is composed mainly of the towns of [[Solnhofen]] and [[Eichstätt]]) is ideal for making [[lithography|lithographic]] plates, and extensive quarrying in the 19th century revealed many fossil finds, as commemorated in the name ''[[Archaeopteryx lithographica]]'', all the specimens of which come from these deposits. The closest modern analogue to the Solnhofen conditions is said to be [[Orca Basin]] in the northern [[Gulf of Mexico]], though that area is much deeper than the Solnhofen lagoons.<ref>Bartell K.W., Swinburne N.H.M. and Conway-Morris S. 1990. ''Solnhofen: a study in Mesozoic palaeontology''. Cambridge (transl. and revised from Bartel K.W. 1978. ''Ein Blick in die Erdgeschichte''. Ott.</ref>
===IUGS geological heritage site=== In respect of the locality being a 'first-class paleontological site displaying high-quality reference material for scientists worldwide, including all known specimens of ''Archaeopteryx'' ', the [[International Union of Geological Sciences]] (IUGS) included the 'Jurassic Solnhofen-Eichstätt Archaeopteryx Serial Site' in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022. The organisation defines an IUGS Geological Heritage Site as 'a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history.'<ref>{{cite web |title=The First 100 IUGS Geological Heritage Sites |url=https://iugs-geoheritage.org/videos-pdfs/iugs_first_100_book_v2.pdf |website=IUGS International Commission on Geoheritage |publisher=IUGS |access-date=13 November 2022}}</ref>
== Paleobiota == {{Main|Paleobiota of the Solnhofen Limestone|Specimens of Archaeopteryx}} Significant members of the Solnhofen paleofauna include ''[[Archaeopteryx]]'', pterosaurs, and marine invertebrates.
== Psilomelane dendrites == [[Image:Dendrit.jpg|thumb|150px|[[Dendrite]]s associated with a fissure on a [[bedding plane]].]] {{main article|Psilomelane|Dendrite}}
[[Dendrite (crystal)|Dendrite]]s, branched dark brown to black [[fractal]] tree-structure, are quite common in the limestone. Such formations are not plant fossil remains, but [[iron oxide|iron]] and [[manganese oxide]]s ([[psilomelane]], {{chem2|(Ba,H2O)2Mn5O10}}) that [[crystallisation|crystallized]] out of solutions on [[bedding plane]]s of the Solnhofen limestone. Dendrites have a chemical-mineralogical origin and are formed by a [[diffusion]] process.
== Cultural items made from Solnhofen Limestone == <gallery> File:1514 Krug Adam und Eva Sündenfall The Fall of Man Bodemuseum anagoria.JPG|Adam and Eve ([[Fall of Man]]), 1514 by Ludwig Krug, [[Bode-Museum]] [[Berlin]] File:1525 Hering Liebesgarten - Jungbrunnen anagoria.JPG|''Garden of Love/Fountain of Youth'', 1525 by [[Loy Hering]] ([[Bode-Museum]] Berlin) File:1530 Kayser Susanna und die beiden Alten anagoria.JPG|''Susannah and the Elders'', 1530 by Victor Kayser ([[Bode-Museum]] Berlin) File:1648 Schweigger Salome with Head of St. John the Baptist anagoria.JPG|Salome Receives the Head of St. John the Baptist in the Dungeon, 1648 by Georg Schweigger </gallery>
== See also == * [[Jura Museum]] * [[List of fossil sites]] ''(with link directory)'' * [[List of types of limestone]] * [[List of dinosaur-bearing rock formations]] * [[South German Jurassic]]
== References == {{reflist}}
== External links == {{Commons category|Solnhofen limestone}} * [http://www.ucmp.berkeley.edu/mesozoic/jurassic/solnhofen.html University of California Berkeley offers a brief introduction] * [http://www.fossilmuseum.net/Fossil_Sites/solnhofen/Solnhofen_Lagerstatt.htm Another brief description of the limestone]
[[Category:Solnhofen Formation| ]] [[Category:Jurassic System of Europe]] [[Category:Limestone formations]] [[Category:Lagoonal deposits]] [[Category:Fossiliferous stratigraphic units of Europe]] [[Category:Paleontology in Germany]] [[Category:Weißenburg-Gunzenhausen]] [[Category:First 100 IUGS Geological Heritage Sites]]