Colorful masses of debris
As Colorful debris masses is known around the Ries encountered ejecta ( "ejecta") that the Ries event some 15 million years ago in the formation of the impact crater were ejected from.
description
The colorful masses of debris were ejected from the inside of the crater by the explosive evaporation of the meteorite on impact and often thrown for kilometers through the air ( ballistic ejection). In the edge zone of the crater, larger blocks were pushed over the surface (roll-slide mechanism). The debris consists mainly of Mesozoic sedimentary rocks ( limestone , clays ) from the most varied of stratigraphic layers, which are found mixed up at random . In between there are also granites and gneisses that originally come from the basement , which is many millions of years older , and can only be found at a depth of about 600 meters if stored undisturbed outside the crater. In contrast to the suevite, the colored debris does not contain any impact glasses or diaplectic glasses .
Originally the colorful rubble masses formed a closed ejecta cover up to a distance of 40 kilometers around the Ries, which was up to 100 meters thick. Today they are mainly found in the south, southeast and east of the Ries. In the megablock zone on the edge of the Ries, some kilometer-sized rock packages lie completely randomly mixed up; the size of the individual rock components decreases with increasing distance from the Ries. Rocks that are so badly smashed and mixed up that their components can no longer be shown individually on a geological map are called colorful breccia .
Ground surfaces
Often the surfaces of the autochthonous rocks on which the colorful debris lie are sanded smooth. These polished surfaces have scratch marks that always point to the center of the Ries crater: Apparently the rock packages on these surfaces have been pushed outwards, which resulted in a further intermingling with the rocks there. Johannes Baier (2007) compared the polished surfaces with those on volcanic chimney walls, such as those found in the Swabian Volcano (Middle Swabian Alb ). There, too, the direction of transport can be demonstrated using the course of the groove.
Shocked fossils
Often in the sedimentary rocks of the colorful debris there are also fossils that show traces of mechanical destruction. Particularly well-known are the Ries belemnites , which were broken into thin slices by the shock wave of the impact and were later cemented back together again, some of which were shifted against each other.
literature
- Johannes Baier: On the origin and importance of the Ries ejection products for the impact mechanism. In: Annual reports and communications from the Upper Rhine Geological Association. 91, 2009, pp. 9-29, doi : 10.1127 / jmogv / 91/2009/9 .
- J. Baier: The ejected products of the Ries impact, Germany , in Documenta Naturae , Vol. 162, Munich, 2007. ISBN 978-3-86544-162-1 ISSN 0723-8428
- J. Kavasch: Ries meteorite crater . Auer Verlag, Donauwörth, 1985. ISBN 3-403-00663-8
- ET Chao, R. Hüttner and H. Schmidt-Kaler: Outcrops in the Ries meteorite crater . Bavarian Geological State Office, 1992. [1]
- CR Mattmüller: Ries and Steinheimer Basin . Ferdinand Enke Verlag, Stuttgart, 1994. ISBN 3-432-25991-3
- R. Hüttner and H. Schmidt-Kaler: Geological map 1: 50000 Ries with brief explanations on the back . Bavarian Geological State Office, 1999 [2]