Solnhofen limestone
Encyclopedia
The Solnhofen Plattenkalk is a Jurassic
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 bird
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 German
state of Bavaria (Bayern)
, halfway between Nuremberg (Nürnberg)
and Munich (München)
and were originally quarried as a source of Lithographic limestone
.
, 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 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 even a few small dinosaur
s. Over 600 species have been identified, including twenty-nine kinds of pterosaur
ranging from the size of a sparrow
to 1.2 m (4 ft) in length have been found.
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 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.
, pterosaurs, and marine invertebrates.
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
Konservat-Lagerstätte
Lagerstätte
A Lagerstätte is a sedimentary deposit that exhibits extraordinary fossil richness or completeness.Palaeontologists distinguish two kinds....
that preserves a rare assemblage of fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
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 bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
Archaeopteryx
Archaeopteryx
Archaeopteryx , sometimes referred to by its German name Urvogel , is a genus of theropod dinosaur that is closely related to birds. The name derives from the Ancient Greek meaning "ancient", and , meaning "feather" or "wing"...
preserved in such detail that they are among the most famous and most beautiful fossils in the world. The Solnhofen beds lie in the German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
state of Bavaria (Bayern)
Bavaria
Bavaria, formally the Free State of Bavaria is a state of Germany, located in the southeast of Germany. With an area of , it is the largest state by area, forming almost 20% of the total land area of Germany...
, halfway between Nuremberg (Nürnberg)
Nuremberg
Nuremberg[p] is a city in the German state of Bavaria, in the administrative region of Middle Franconia. Situated on the Pegnitz river and the Rhine–Main–Danube Canal, it is located about north of Munich and is Franconia's largest city. The population is 505,664...
and Munich (München)
Munich
Munich The city's motto is "" . Before 2006, it was "Weltstadt mit Herz" . Its native name, , is derived from the Old High German Munichen, meaning "by the monks' place". The city's name derives from the monks of the Benedictine order who founded the city; hence the monk depicted on the city's coat...
and were originally quarried as a source of Lithographic limestone
Lithographic Limestone
Lithographic limestone is hard limestone that is sufficiently fine-grained, homogeneous and defect free to be used for lithography. Geologists use the term lithographic texture to refer to a grain size under 1/250 mm...
.
Paleoenvironment and preservation
During the Late JurassicLate Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...
, this area was an archipelago
Archipelago
An archipelago , sometimes called an island group, is a chain or cluster of islands. The word archipelago is derived from the Greek ἄρχι- – arkhi- and πέλαγος – pélagos through the Italian arcipelago...
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
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, 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
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
mud. Thus, many delicate creatures avoided consumption by scavengers or being torn apart by currents. The wings of dragonflies
Dragonfly
A dragonfly is a winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera . It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...
, the imprints of stray feather
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
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
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
.
At times, the lagoons almost dried out, exposing sticky carbonate muds that trapped insects and even a few small dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s. Over 600 species have been identified, including twenty-nine kinds of pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
ranging from the size of a sparrow
Sparrow
The sparrows are a family of small passerine birds, Passeridae. They are also known as true sparrows, or Old World sparrows, names also used for a genus of the family, Passer...
to 1.2 m (4 ft) in length have been found.
The fine-grained texture of the mud silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
forming the 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....
from the Solnhofen
Solnhofen
Solnhofen is a municipality in the district of Weißenburg-Gunzenhausen in the region of Franconia in the Land of Bavaria in Germany. It lies within the Altmühl valley....
area (which is composed mainly of the towns of Solnhofen
Solnhofen
Solnhofen is a municipality in the district of Weißenburg-Gunzenhausen in the region of Franconia in the Land of Bavaria in Germany. It lies within the Altmühl valley....
and Eichstätt
Eichstätt
Eichstätt is a town in the federal state of Bavaria, Germany, and capital of the District of Eichstätt. It is located along the Altmühl River, at , and had a population of 13,078 in 2002. It is home to the Katholische Universität Eichstätt-Ingolstadt, the lone Catholic university in Germany. The...
) is ideal for making lithographic
Lithography
Lithography is a method for printing using a stone or a metal plate with a completely smooth surface...
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
Orca Basin
The Orca Basin is a mid-slope, silled, mini-basin in the northern Gulf of Mexico some 300 km southwest of the Mississippi River mouth on the Louisiana continental slope. It is unique amongst the mini-basins in this area, in containing a large brine pool of anoxic salt brine...
in the northern Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
, though that area is much deeper than the Solnhofen lagoons.
Paleobiota
Significant members of the Solnhofen paleofauna include ArchaeopteryxArchaeopteryx
Archaeopteryx , sometimes referred to by its German name Urvogel , is a genus of theropod dinosaur that is closely related to birds. The name derives from the Ancient Greek meaning "ancient", and , meaning "feather" or "wing"...
, pterosaurs, and marine invertebrates.
See also
- List of fossil sites (with link directory)
- List of types of limestone
- List of dinosaur-bearing rock formations