Schrattenkalk Formation


The Schrattenkalk Formation is a Barremian to Aptian geologic formation in the Alps. The limestone is highly karstified. Fossil ornithopod tracks have been reported from the formation. Iguanodont tracks have been registered in the Swiss portion of the formation. The famous north face of the Eiger is partly composed of Schrattenkalk, as well as the Sturmannshöhle in southernmost Bavaria, Germany, and the Hölloch and Silberen system karst caves in Switzerland.

Description

The formation is named after the Schrattenfluh in Luzern, Switzerland. The name is derived from the Swiss-German "Schratten" meaning clints or lapies, a phenomenon that frequently affects the limestone. Kalk is limestone in German. Synonyms for the extensive formation are Hieroglyphenkalk, Calcaire à Hippurites, Urgonien, Rudistenkalk, Urgo-Aptien, Schrattenschichten, Requienenkalk, Rhodanien, Caprotinenkalk, and Urgonian Limestone. The formation consists of three units, the Lower Schrattenkalk, Rawil Member and Upper Schrattenkalk.
The upper and lower units consist mostly of reefal limestones with bryozoa, gastropods, corals, sponges, brachiopods, bivalves and rudists. The Rawil Member contains beds of sandstones and mudstones containing foraminifera and echinoderms. The upper and lower members represent a photozoan-dominated carbonate platform, and was deposited at the northern edge of the Tethys Ocean.

Fossil content

In 2015, two new corals were described from Austria; Cairnsipsammia, and Paraclausastrea vorarlbergensis.
In an abandoned quarry on the shore of Lake Lucerne, close to the village of Beckenried, fossil trackways were discovered in the formation. The steeply inclined surface has more than 50 tracks of ornithopod dinosaurs that are attributed to iguanodontids. Three trackways can be followed for distances of. The lengths of the footprints have a mean of and point to animals ranging in size of, with estimated hip heights between and.