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Nördlinger Ries


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View of Nördlinger Ries


The crater rim near the village of Mönchsdeggingen For human settlement
within the Nördlinger Ries region, see Donau-Ries .

The *Nördlinger Ries* is a large circular depression in western Bavaria ,
Germany , located north of the Danube in the district of Donau-Ries . The
city of Nördlingen is located about 6 kilometers (3.7 mi) southwest of
the centre of the depression.

The word "Ries" is not a German word; it is believed that the term is
derived from Raetia , since the tribe of Raetians lived in the area in
pre-Roman times. The addition "Nördlinger"^[/clarification needed /] is
actually redundant, as there is no other place called Ries.


[edit ] Ries impact crater

The depression is interpreted as a meteorite impact crater formed about
14.3 million–14.5 million years ago in the Miocene .^[1] ^[2] The crater
is most commonly referred to simply as the *Ries* or *Ries crater*. The
original crater rim had an estimated diameter of 24 kilometers (15 mi).
The present floor of the depression is about 100–150 meters below the
eroded remains of the rim.

It was originally assumed that the Ries was of volcanic origin. In 1960
two American scientists, Eugene Shoemaker and Edward Chao , proved that
the depression was caused by meteorite impact. The key evidence was the
presence of coesite (shocked quartz ), which, in natural unmetamorphosed
rocks can only be formed by the shock pressures associated with meteorite
impact. The coesite was found in the building stone (suevite) of the
Nördlingen town church, constructed from locally derived stone.^[3]

Two petrographical papers of Johannes Baier have shown that suevite was
formed from mesozoic sediments. ^[4] ^[5]

Another impact crater, the much smaller (3.8 km diameter) Steinheim crater
, is located about 42 kilometers west-southwest from the centre of Ries.
The two craters are believed to have formed nearly simultaneously by the
impact of a binary asteroid .

Recent computer modeling of the impact event indicates that the impactors
probably had diameters of about 1.5 kilometers (4,900 ft) (Ries) and 150
meters (490 ft) (Steinheim), had a pre-impact separation of some tens of
kilometers, and impacted the target area at an angle around 30 to 50
degrees from the surface in a west-southwest to east-northeast direction.
The impact velocity is thought to have been about 20 km/s (45,000 mph).
The resulting explosion had the power of 1.8 million Hiroshima bombs .

The Ries crater impact event is believed to be the source of moldavite
tektites found in Bohemia and Moravia (Czech Republic ). ^[6] The tektite
melt originated from a sand-rich surface layer and was ejected to
distances up to 450 km downrange of the crater.

Stone buildings in Nördlingen contain millions of tiny diamonds , all
less than 0.2 millimeter across. The impact that caused the Nördlinger
Ries crater created an estimated 72,000 tonnes of them when it impacted a
local graphite deposit. Stone from this area was quarried and used to
build the stone buildings.^[7]



[edit ] References

1. *^ * "Ries" . /Earth Impact Database /. University of New Brunswick .
http://www.unb.ca/passc/ImpactDatabase/images/ries.htm. Retrieved
2008-12-30.  2. *^ * J. Baier: /Zur Herkunft und Bedeutung der
Ries-Auswurfprodukte für den Impakt-Mechanismus/ . - Jber. Mitt.
oberrhein. geol. Ver., N. F. 91, 9-29, 2009. 3. *^ * Exploring Space: The
Quest for Life, 2005, Nova. 4. *^ * J. Baier: /Die Auswurfprodukte des
Ries-Impakts, Deutschland/, in /Documenta Naturae/, Vol. 162, München,
2007. ISBN 978-3-86544-162-1 5. *^ * J. Baier: /Zur Herkunft der
Suevit-Grundmasse des Ries-Impakt Kraters/, in /Documenta Naturae/, Vol.
172, München, 2008. ISBN 978-3-86544-172-0

6. *^ * G. Graup, P. Horn, H. Köhler & D. Müller-Sohnius: Source
material for moldavites and bentonites. In Naturwissenschaften. Vol. 67,
Berlin, 1981. 7. *^ * Emsley, John (2001). /Nature's Building Blocks/.
Oxford University Press , pp. 99. ISBN 0-19-850341-5 .


[edit ] External links

Search Wikimedia Commons
	Wikimedia Commons has media related to: /*Nördlinger Ries */

* Ries at Earth Impact Database

* Ries Crater Museum Nördlingen * Travel for Kids: Nordlingen, Germany

* Information on meteorite and aerial photo of town, scroll two thirds of
the way down page


Coordinates : 48°53′N 10°34′E / 48.883°N 10.567°E / 48.883; 10.567