Aus aktuellem Anlass möchte ich noch einmal auf die Entstehung des Tüttensees eingehen. Denn in seiner Erwiderung auf die Ergebnisse der Tüttenseedatierung behauptet Ernstson, zum Thema Toteislöcher: " ...ist bis auf den heutigen Tag von Geologen und Geografen kein einziger Beleg (!) für eine eiszeitliche Genese des Tüttensees mit der Bildung eines Toteiskessels erbracht worden ". Dies entspricht nicht den Tatsachen. Die Toteisgenese des Tüttensees ist in der geowissenschaftlichen Literatur durchaus belegt. Allerdings in etwas älteren Quellen, die im Internet schwer oder gar nicht zu finden sind, und daher den Gang in eine gut sortierte Bibliothek erfordern.
Jedenfalls liegen durchaus Untersuchungen vor, die auch die Chiemseegegend und ausdrücklich den Tüttensee mit einschließen. Neben der gut dokumentierten geologischen Kartierung von Ganns (1977), hat Josef Gareis bereits im Jahr 1978 die Toteisgenese des Tüttensees mit geomorphologischen und sedimentologischen Untersuchungen nachgewiesen. Er widmet dem Tüttensee mehrere Seiten und beschreibt die geomorphologische Situation wie folgt:
"[...] The hollow form of Tüttensee is surrounded by a wall about 50 m wide with a completely flat crown a smaller pool closes to the east .
Gareis is believed that after the collapse of the Chiemsee glacier tongue there are two dead ice blocks remained, which were then eingeschottert by melt waters of the following interstadial. " It took the form of an 8-ring double Tüttensee terrace (see Figure 1). These observations have recently of Doppler & Geiss (2005) been confirmed. In their work, these structures can also be based on a beautiful 3D image understand very well. Here, incidentally, also shows that there is a circular wall in the strict sense does not exist, but the northern edge of the terrace, but continues in the direction of ENE.
are there to make statements only because of terrain features in the formation history is difficult, Gareis also in his work the terraces studied sedimentological, to distinguish them from moraines can. These are classified, he cobbles to the shape and degree of roundness and measured their orientation in space. Fortunately, he has this Tüttensee performed two measurements. One of them in the NW outer edge of the terrace, the other on the SW inner edge of the terrace.
In both outcrops, he was mounted horizontally, well-adjusted, mostly very rounded components Calibrate. It is noteworthy here is how much the sedimentological features, namely degree of roundness and the identical orientation of the pebbles, same in both outcrops. Gareau also found that the sediments are depleted in fines.
It was a casual Gareis reconstruct former NE-SW direction of transport of sediment by meltwater interstadials, which led to a ballasting the dead ice blocks, and thus the formation of the Tüttensee terraces.
These observations are in direct contradiction to a Impaktgenese, because the sediments show, contrary to the assertions of the CIRT, not even all the characteristics of so-called Diamictites. But they correspond perfectly to the expectations of the above-mentioned sedimentological terracing, they reflect the dynamics of ballasting the dead ice blocks melt-water masses.
Literature:
Gann, O. et al. (1977): Notes on Geological Map of Bavaria 1:25000, sheet 8140, Prien am Chiemsee and Bl 8141, Traunstein, 344 pp.
Gareis, J. (1978): The Toteisfluren of the Bavarian Alps as a testament to the type of spätwürmzeitlichen Eisschwundes , Wurzburg Geographical work, Würzburg, 101 pages
Doppler, G. & Geiss, E. (2005 ): The Tüttensee im Chiemgau - instead Toteiskessel impact crater. Bayerisches Geologisches Landesamt, http://www.lfu.bayern.de/geologie/fachinformationen/meteoriten/doc/tuettensee.pdf .
