Geomorphological Development of the Písek Area (Southern Bohemia)
Authors: Přibylová Nora , Viktorová Hana , Vojna Ladislav , Jeřábek Jan 
Published: October 2023

A detailed geomorphological investigation of this area has been carried out by workers of the Department of Physical Geography of the Faculty of Natural Sciences at the Charles University. The investigation was carried out by mapping in scale 1 : 25 000. The results of the mapping were then reproduced in scale 1: 50 000. In the enclosed geomorphological map the surface phenomena were divided from the development point of view into destructive phenomena (denudation and erosion) and accumulative phenomena which may be divided still further. The geological basis is predominantly formed by crystalline rocks of the Molda nubicum which forms part of the core of the Bohemian Mass. Most frequent are different kinds of paragneiss, migmatites, and subsurface and vein eruptives of granitic character. Depressions predetermined by the tectonic pattern are filled with continental Upper Cretaceous and Tertiary sediments of the Budějovice basin. The oldest and basic phenomenon of the whole southern Bohemia are the remnants of the South Bohemian peneplain. In the area represented in the geomorphological map this phenomenon has not been preserved at all. We presume that remnants of the peneplain dissected by vertical movements occur in the substratum of Tertiary sediments which fill predominantly tectonic depressions. The denudation activity going on on the peneplain has resulted in the formation of gentle slopes, denudation plains and monadnocks. The nearest situated remnants of the peneplain occur more to the east in the environment of Týn n/V at altitudes of 450-500 m. There are three kinds of denudation plains in this area: petrographically predetermined plains, plains of river origin, saddle type and peak type plains. Structural-denudation plains composed of Tertiary sediments have been predominantly concentrated to the area between Čejetice, Cehnice and Mladějovice. They form several levels. Their surface is formed by horizontally deposited Tertiary sediments of a past South Bohemian lake. In the mapped area gentle denudation slopes occur most often and form almost a half of the total area. Their gradient ranges from 1-6°, most often from 3-4°. In the relief of the Mehelník Hills in the north-eastern part of the map abrupt denudation slopes are the prevailing phenomena. They often follow the valleys of streams. From the denudation plains and slopes numerous monadnocks are rising. They usually are strictly elongated in one direction, usually from north-north-west to south-south-east, and from north west to south-east. The river Otava - crossing the area in question - has formed here only one continuous terrace level with prominent alluvial terraces 5 to 15 m high above the surface of the river. Judging by its connection with the terrace system of the Vltava and the Labe this level may date from the Riss. From higher situated river terraces of the Otava only small denudation remnants have been preserved. On the river Blanice - besides two small denudation remnants in the area represented in the enclosed map - no terraces have been preserved. Both above-mentioned rivers have built wide alluvial flood-plains along the greater part of their courses in this area.