Solnhofen limestone
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The Solnhofen limestone is a Jurassic lagerstätte that preserves a rare assemblage of fossilized organisms, some of which, such as sea jellies, don't ordinarily fossilize at all. Others, like the early bird Archaeopteryx are 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, halfway between Nuremberg and Munich. During late Jurassic times, 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 feathers, 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 dinosaurs. 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 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.
External links
- University of California Berkeley offers a brief introduction. (http://www.ucmp.berkeley.edu/mesozoic/jurassic/solnhofen.html)
- Another brief description. (http://www.fossilmuseum.net/Fossil_Sites/solnhofen/Solnhofen_Lagerstatt.htm)