The Dyje Canyon-like Valley: Geomorphological Landscape of Deep Valley at the Eastern Part of the Marginal Slope of Bohemian Massif

Abstract

Southeastern margin of the Bohemian-Moravian Highland is cut by deep river valleys with incised meanders . The Canyon-like Valley of the Dyje River belongs to the most important and attractive of them. The valley is embedded into the Paleogene regional planation surface (etchplain ) within the hilly land relief, creating sharp morphological contrasts, unique in the Bohemian Highland and in the adjacent part of Austria. The deep valley of Dyje River has become a strategic river since the Middle Ages , because the valley traditionally formed the border between Austrian countries and the Kingdom of Bohemia. In the period of the Cold War, the area was closed to the public for more than 40 years as it was a part of the “iron curtain ”. After political changes in the Czech Republic Europe in 1989, the border area was open to the public. Due to rare landscape phenomenon (including landforms), the Dyje valley with its surroundings was declared a national park in 1991 (Podyjí National Park ). On the Austrian side of the Dyje River valley, the national park Thayatal was declared in 2000. Three basic relief types have been defined in the study area: (i) Polygenetic regional planation surface, (ii) Fluvial canyon-like valley of the Dyje River and its tributaries and (iii) Polygenetic marginal slope of Bohemian Highland. Within these relief types, a few unique sites are located, related to fluvial erosion, periglacial remodelling of rock slopes , selective weathering and denudation. Special attention is devoted to site with Ice caves within the largest rock slide in the area, which conditioned the origin of the longest pseudokarst cave system in crystalline rocks in the Czech Republic.