Jeseníky Protected Landscape Area

Geomorphology

The Hrubý Jeseník mountains are a mountain range with a relatively rugged terrain with a basic structure of stepped areas. From the centre of the mountain range the surface falls in all directions in a series of stepped areas, separated slopes and saddles. Several generations of landforms which were formed in various geological periods due to the effects of exogenic agents have been preserved in the Jeseníky landscape relief. The Hrubý Jeseník range is separated from the Rychlebské hory Mountains by the Ramzovské sedlo saddle and from the Nízký Jeseník Range along a line between the towns of Zlaté Hory, Vrbno pod Pradědem and Rýmařov. The mountain range, which was formed by several orogenic processes, has been worn down by long-term denudation processes ever since the late Palaeozoic era.

The denudation processes peaked during the Lower Cretaceous to Oligocene periods with the formation of a peneplain. The most important factor in the formation of the present landscape relief of the Hrubý Jeseník range with its montane character, deeply-carved valleys with high, straight slopes and wide saddles were the later tectonic movements which broke up the original peneplain into blocks lying at varying elevations, segmented by NW–SE faults. On the peak areas of the Hrubý Jeseník range the peneplaned relief character is still mostly intact, and the mountain range consists of several basic blocks, which are separated by tectonic lines:

  • The central block of Praděd
  • The north–western Block of Keprník
  • The north–eastern system of smaller blocks, forming the Jesenická kotlina basin
  • The north–eastern block of Medvědí vrch.

The uplifting of the Hrubý Jeseník blocks also renewed the erosional activity of the streams, which carved into the blocks and formed today’s typically V-shaped valleys. The effects of mountain glaciers during the Ice Ages can be seen in the spring depressions at the heads of some valleys with wider amphitheatres around them. Examples of these phenomena are the spring depressions on the streams flowing down the eastern slopes of Hrubý Jeseník of which the Velká kotlina glacial cirque (the spring depression of the Moravice river) shows us a number of glacial elements in its relief. Here we can see steep cirque walls, two cirque floor levels, and a notable frontal moraine. Among the typical periglacial landforms, which formed as a result of frost weathering in its relief. Here we can see steep cirque walls, two cirque floor levels, and a notable frontal moraine. Among the typical periglacial landforms, which formed as a result of frost weathering in front of the glaciers flow are the cryoplanation terraces and the frost-riven cliffs. As the terraces joined together they formed peak area plateaux. Extensive cryoplanation terraces in Hrubý Jeseník developed around Petrovy kameny rocks, on the main mountain ridge, on Žárový vrch near Ludvíkov and on Mt. Keprník.

The existence of long-term frozen soils is illustrated by the occurrence of frost-sorted polygonal grounds, garland grounds and thufur. Examples are the polygonal grounds around the frost-riven cliffs on Petrovy kameny rocks, thufur on Keprník and the boulder streams on Břidličná. On the saddles and flat-topped peaks mountain raised bogs, which began to form in the postglacial (Atlantic) period can be found. The largest mountain raised bog in Moravia and Silesia is at Rejvíz, and at Skřítek we can find transitional mire (a mountain bog on the saddle transforming from a raised bog to a fen). Smaller raised bogs can be found at several other localities: near the Švýcárna chalet, under Petrovy kameny, on Máj, on Malý Děd, under Vozka, on Trojmezí and in the Velká Jezerná area.