Stop 9 at Ries

Near the entrance to the Otting quarry
Photo: G. Osinski, University of Western Ontario
Location: 3.5 kilometers east of the crater rim

Suevite door frame
Photo: G. Osinski, University of Western Ontario
Location: 3.5 kilometers east of the crater rim
Scale: Height of the door is 2 meters

Here in Otting is the largest quarry of suevite. Like many others at the Ries structure, it is no longer operating and is overgrown by vegetation. But, there is still a lot to see!

As we saw in Nördlingen at the start of our tour, suevite has been used to construct buildings in this region of Bavaria for centuries. Although we can't tell for sure, it's likely that the suevite for this house (above picture) came directly from the neighboring Otting quarry. Most of the suevite in the quarry, however, was used for making cement at the Märker cement plant in Harburg, just outside the southwest crater rim.

Geologist Gordon Osinski talks about the geology of Otting quarry

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Close-up of suevite in the Otting quarry
Photo: G. Osinski, University of Western Ontario
Location: 3.5 kilometers east of the crater rim
Scale: Length of the pen is 12 centimeters

The Otting quarry is important as it was here that Eugene Shoemaker and Edward Chao first discovered coesite, a very high-pressure polymorph of quartz. This proved that the Ries structure was a meteorite impact crater and not a volcanic crater that many had previously believed.

Unlike the suevite ejecta we've seen at previous stops, the Otting quarry lies outside the final crater rim. This shows us that suevite ejecta travelled considerable distances and was deposited both inside and outside of the final crater rim. The suevite of the Otting quarry is particularly glass-rich.

Close-up of suevite in the Otting quarry
Photo: G. Osinski, University of Western Ontario
Location: 3.5 kilometers east of the crater rim
Scale: Width of the lens cap is 6 centimeters

Lets look at the clasts in the suevite. As we can see here, many of the crystalline rocks are very strongly shocked and surrounded by a thin layer of black glass. This indicates that the glass was still liquid as the fragment of gneiss was being transported to its final destination. Keep your eyes open for fragments of sedimentary rock in the suevite. While they are quite rare, they can be found here at Otting.