Solnhofen limestone

Solnhofen Limestone Formation Stratigraphic range: Tithonian
Type	Geological formation
Underlies	Mornsheim Formation
Overlies	Roglings Formation
Lithology
Primary	Lithographic Limestone
Location
Country	Germany

The Solnhofen Plattenkalk, or Solnhofen limestone, is a Jurassic Konservat-Lagerstätte that preserves a rare assemblage of fossilized 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 German state of Bavaria (Bayern), halfway between Nuremberg (Nürnberg) and Munich (München) and were originally quarried as a source of Lithographic 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 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 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.

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Wikipedia