Aalen Stage

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Aalen Stage

 

the bottom layer of the Middle Jurassic System, named after the city of Aalen in the southwest part of the Federal Republic of Germany. It was isolated by the Swiss geologist and stratigrapher Meyer-Eimar in 1864. In a typical cross section it is represented by black marl with Harpoceras opalinum and ferruginous oolites with Harpoceras murchisonae. It is widespread in the geosyncline of the Tethys Sea in the Alps, the Caucasus, and other mountain structures.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.