Geology is an essential source of knowledge for understanding the processes on earth. The mineral resources of the earth (ores, rocks) and the landscape forms with the associated water systems are important foundations of life and economy.
The Aalener Bucht is part of the Swabian stratigraphic plain and is framed by the limestone mountains of the of the Swabian Alb. The Jurassic strata (formed 200 - 145 million years ago) are divided into:
| Weissura (White Jurassic) | MALM | Limestones of the Alb and the Alb ridge |
| Braunjura (Brown Jurassic) | DOGGER | clays and sandstones of the Albrand |
| Schwarzjura (Black Jurassic) | LIAS | Shales and marls of the Alb foreland |
The lower brown jurassic is called worldwide AALENIUM. The Aalenium (shortened also Aalen, also Aalenien) is in the earth history the oldest of the four chronostratigraphic stages of the Middle Jurassic and covers geochronologically the period of about 174.1 to 170.3 million years. The stage is named after the city of Aalen. The stage and the name were first used by Karl Mayer-Eymar in 1864. The first fossil finds were made, among others, in the Tiefen Stollen (visitor mine) in Aalen.
The Opalinus Clay of the lower Aalenian, forms the base of the Aalen Bay. The Opalinus Clay Formation is a lithostratigraphic formation of the South German Jurassic. It is distributed almost in the whole area of the South German Jurassic. It is underlain by the Jurensismergel Formation and overlain by the Eisensandstein Formation (upper Aalenian) in the Swabian Alb.
Aalen is part of the UNESCO Geopark Swabian Alb and has three Geopark information points: Tiefer Stollen (visitor mine), Urweltmuseum (Geological Museum) and Explorhino. The Tiefer Stollen is an exhibition mine and shows the ore mining of earlier times, which also contributed significantly to the development of Wasseralfingen and Aalen. The prehistoric museum shows the geology of the region and the development of the earth and life. The Explorhino combines natural science experiments with geological knowledge.
