Aumühle quarry
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The Aumühle quarry is a quarry near Aumühle , a district of the municipality of Hainsfarth in the Swabian district of Donau-Ries in Bavaria .
location
The quarry is located about 1.3 kilometers north of Hainsfarth in the Nördlinger Ries .
description
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The quarry shows the rock masses created by a meteorite impact in the Nördlinger Ries almost 15 million years ago during the Ries impact . These are known as colorful breccia and gray, tuffähnlichem Suevite deposited one above the other. For a long time, the Nördlinger Ries was assumed to be volcanic . It was not until 1961 that clear evidence of a meteorite impact was found. At the time of the Tertiary , a stone meteorite about one kilometer in size hit the Franconian-Swabian Alb at a speed of at least 70,000 km / h. The meteorite itself evaporated. Pressure and heat waves extinguished all life within a radius of well over 100 kilometers. An impact crater up to four kilometers deep and a diameter of 25 kilometers was created . The rock below the crater was smashed to a depth of several kilometers, extremely compressed and partially melted. The rock was also thrown up and to the side. The colorful breccia was created. Part of it subsequently slipped back into the crater. Huge amounts of dust, ash and larger, partly melted rock debris were hurled into the stratosphere and then rained down from there. The result was the suevite which covered the already deposited variegated breccia.
The Aumühle quarry thus contains the two typical stone products, the colorful breccia below and suevite above. On the east side of the quarry, the deposit of glass-rich suevite on colorful breccia is exposed. The colorful breccia here consists mainly of reddish and brownish Keuper and Dogger rocks. Between the suevite and the colorful breccia there is a thin transition zone with fine-grain suevite. The colorful breccia consists of a mixture of the rocks present at the point of impact ( gneisses and granites from the basement, red and brown Triassic sediments and limestone from the Upper Jurassic ). The size of the particles ranges from fine rock dust to meter-sized blocks. The suevite is similar to the volcanic tuff and consists of a fine gray matrix. In this, rubble of the previously existing rock, partly in molten form ( glass flakes ), is enclosed. In the meantime, " shatter cones " have also been detected in the impact rocks .
The "little brother" of the Ries crater is the Steinheim Basin, about 45 kilometers to the west . It was probably created at the same time as the Ries by a small "companion" of the Ries meteorite, a so-called "moon" or by a fragment of the actual Ries meteorite.
In the Ries crater itself, an outflow-free lake formed after the impact, in which precipitation and evaporation were balanced in the prevailing subtropically changeable climate. The water depth was therefore never great and at times the lake fell dry. In 2 million years, clays with a thickness of 300 meters with small brown coal seams and fossil-rich limestone were deposited here. Only when the Wörnitz broke through the rim of the crater later did this lake run empty.
Use of the Ries rocks
Especially in the Middle Ages, suevite was used as an easily workable building block in many regional buildings. The Daniel , the 90 meter high landmark of the city of Nördlingen, was built from suevite. Today, however, the tower also shows the susceptibility of suevite to weathering and numerous open and repaired breakouts can be found in the masonry.
Access
The quarry is still in operation. There is a display board in front of the entrance and a telephone registration with the Märker company is necessary before entering.
Geotope
The quarry has been designated by the Bavarian State Office for the Environment (LfU) as a geoscientifically valuable geotope (geotope number: 779A013). It was also awarded the official seal of approval for Bavaria's most beautiful geotopes by the LfU .
See also
Individual evidence
- ↑ Location of the quarry in the Bavaria Atlas (accessed on October 26, 2017).
- ↑ Johannes Baier: Suevite - the "Schwabenstein" from the Nördlinger Ries. Fossils, 35 (3), Wiebelsheim 2018.
- ↑ Volker J. Sach & Johannes Baier: New investigations on radiant limestone and shatter cones in sedimentary and crystalline rocks (Ries impact and Steinheim impact, Germany) . Pfeil-Verlag, Munich 2017. ISBN 978-3-89937-229-8 .
- ^ Bavarian State Office for the Environment, Geotop Steinbruch NE von Hainsfarth (accessed on October 26, 2017).
- ↑ Bavaria's most beautiful geotopes, Aumühle quarry (accessed on October 26, 2017)
Web links
Coordinates: 48 ° 58 ′ 14.6 " N , 10 ° 37 ′ 45.2" E