Nördlinger 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 6km southwest of the centre of the depression."Ries" is derived from Raetia, since the tribe of Raetians lived in the area in pre-Roman times.Ries impact craterThe depression is interpreted as a meteorite impact crater formed about 14.3 million–14.5 million years ago in the Miocene. The crater is most commonly referred to simply as the Ries or Ries crater. The original crater rim had an estimated diameter of 24km. The present floor of the depression is about 100to below the eroded remains of the rim.It was originally assumed that the Ries was of volcanic origin. In 1960 Eugene Shoemaker and Edward C. T. Chao showed that the depression was caused by meteorite impact. The key evidence was the presence of coesite, which, in unmetamorphosed rocks, can only be formed by the shock pressures associated with meteorite impact. The coesite was found in the locally derived suevite building stone of the Nördlingen town church. The suevite was formed from mesozoic sediments shocked by the bolide impact.