Geology
The Rock Types of the Ries Crater
A mixed breccia composed of rock fragments of different colour (Bunte Breccia)

When the crater was formed, the various target rocks were shattered (fragmented), ejected, turbulently mixed, and deposited outside the crater as a continuous blanket. It consists of chaotically mixed rock fragments which originate from different bedrock formations. As these display different colours, the chaotic („polymict“) breccia appears multicoloured. This lead to the name “Bunte (multi-coloured) Breccia”.

 

The proportions of the various rock components in the Bunte Breccia, which originate from different levels of the target rock section, vary considerably from place to place, and also in their size, ranging from fine dust to kilometre-sized blocks. Rocks from the lowest target levels (granite, gneiss, amphibolite) are white, grey, dark green, and reddish. Rock pieces from the upper Triassic have lightgrey, green, and reddish colours. Together with various rocks of the Jurassic period (yellow to light-grey limestones, dark-grey clays, beige to red sandstones) and light-coloured sands from the early Tertiary time, they provide an interesting interplay of colours. All rocks of the Bunte Breccia were subjected to lower pressures and temperatures than the components in the suevite, which formed a “hot” layer deposited on top of the “cold” Bunte Breccia.

multicolored fragmented ejecta masses White Jurassic (Malm) Keuper (Upper Triassic)
Quaternary sediment Brown Jurassic (Dogger) Ries-lake sediment (Tertiary)
Suevite Black Jurassic (Lias)  


Glass bomb from the Suevit from Otting



Impact diamond from the Ries crater

Suevit

The cosmic catastrophe created a new rock type: Suevite (from the Latin suevia = Swabia). Suevite is a so-called impact breccia, which is composed primarily of fragments of granite and gneiss from the crystalline basement and of lumps of molten crystalline bedrock. Suevite was formed by a turbulent flow inside the transient crater and when the hot debris cloud above the crater collapsed and fell back into the crater and on top of the ejecta blanket.

 

The rock fragments within suevite reveal that they were subjected to different degrees of pressure and temperature (“impact or shock metamorphism”). The special feature of the suevite is the presence of lumps of molten rocks („glass bombs“ also called „Flädle“). The mystery about the origin of the Ries crater was solved in 1960 and 1962 through the analysis of the suevite that lead to the discovery of the high-pressure forms of quartz, the minerals coesite and stishovite. Later, also diamond was found. These minerals which are typical for impact deformed rocks can be regarded as “fingerprints” of the cosmic bodies impacting the Earth. The term suevite is used today for corresponding rocks occurring in all impact craters both on Earth, on the moon and on other planets.



Edward Chao (left) and Eugene Shoemaker (right), who identified the Ries as an impact crater

Suevite in contact with Bunte Breccia in the Aumühle quarry near Oettingen

Contact of Bunte Breccia and Upper Jurassic limestone (Malmian) in the Gundelsheim quarry

Suevite in contact with displaced Upper Jurassic limestone in the Altenbürg quarry

Further topics:



Science
Meteorite and Impact Research

In August 1970, NASA conducted geological fi eld training in the Ries crater for the astronauts of the Apollo 14 and 17 missions.


more
Agriculture and Industry
The economic wealth of the Ries

The bedrock formations, the resulting soils, and the climate have made the Ries the “corn basket” of Bavaria. Cereals have been planted in the Ries since the 6th century BC. Since about 1800 root crops and fodder plants have also been cultivated.(www.rieser-bauernmuseum.de)


more
Geology and architecture
Geology and architecture

Suevite, which was created by the Ries impact event, has been used as building stone in the Ries and the surrounding areas already by the Romans. Especially in the Middle Ages it became the building material for numerous buildings in Nördlingen and its surroundings. The cathedral of St.George , for example, with its tower called “Daniel”, is built almost entirely of suevite. It is not known exactly whether the
building material came from just one quarry, the quarry of Altenbürg.

Suevite has not only been used for the construction of churches, but also for other buildings of non-religious character in the region around the Ries and beyond.
In Nördlingen parts of the City Hall, the Baldingen Gate and other gates of the city wall, as well as parts of the city fortifications (e.g. the Berger wall), have been built with this material. In the area around
Nördlingen, suevite was used at Harburg and for a number of village churches. In Munich suevite building stones can be admired at the German Museum and the former Royal Bavarian Traffic Ministry. Even
Berlin hosts several suevite buildings.


more
 back top
Landkreis Donau-Ries - Geopark Ries - Geschäftsstelle - Pflegstraße 2 - 86609 Donauwörth