Deeply Incised Valley Meanders of the Bohemian Massif

The marginal eastern parts of the Bohemian Massif in Austria are characterized by incised valley meanders, which have formed in response to tectonic uplift and river channel incision starting before c. 5 Ma. The most impressive examples of incised valley meanders are located in the Waldviertel Highlands along the Thaya, Kamp and Krems rivers. In this chapter, some hotspot examples with canyon-like incised meanders and related other landforms with a special focus on the Thayatal National Park are presented. The Thayatal National Park is the smallest out of six Austrian national parks and is connected to the larger Czech Podyjí National Park. In the Thayatal National Park, an impressive example of a double bend meander can be found at Umlaufberg and Ostroh, caused by highly resistant orthogneisses in the western meander neck, which forced the river to flow around. At some locations, the Thaya Valley is cut into the Thaya granite and Biteš gneiss, and characterized by steep valley sides, castellated rock outcrops, boulder fields and block streams. Boulder fields and block streams developed by unloading of rocks in the Late Pleistocene and were accentuated during the Holocene by gravitational slope processes. Along the Kamp and Krems valleys, deeply incised valley meanders similar to those found along the Thaya Valley have formed. In the lower courses of the Kamp and Krems valleys, well-preserved Pleistocene loess profiles with several pedocomplexes (e.g. the Stiefern loess sequence in the Kamp Valley) can be found, serving as indicators of landscape evolution and palaeoclimatic changes. Moreover, along the Krems River impressive cave systems can be observed, such as the “Gudenushöhle”, which is considered to be one of the earliest human settlements in Austria.