Geografie 1963, 68, 317-327

https://doi.org/10.37040/geografie1963068040317

Geomorphological Development of the Country of Týn nad Vltavou, Southern Bohemia

K. Mazáčová1, V. Přibyl1, J. Chrobok1, B. Kepková1, V. Král2, J. Kunský2

1Praha 2, Albertov 6, Czechia
2Katedra fysické geografie a kartografie PF KU, Praha 2, Albertov 6, Czechia

For this country has been made a geomorphological map in the field scale of 1 : 25000, given here in diminished scale. The geological structure of this peneplenised country is formed by folded and faulted paragneises, migmatitic gneises with smaller veins of different types of granitic vein-rocks. Remnants of the tertiary lake deposits, reduced by denudation, form sands, gravels and clays of miocene and pliocene age. The oldest surface form of this country is south-bohemian peneplain with monadnocks, of the upper-cretaceous age. The surface of the peneplain lies between 450 m a. s. l. in the north and 490 m in the south of the country. Erosion of the rivers Vltava and Lužnice and their brook-affluents with asymetric widely spaced valleys reduced the peneplain into narrow stripes of NNW and NW directions. Parts of the river valleys and most of brook valleys are tectonically predisposed. The widespread form of the country are denudational long gentle slopes (1°-6°) resulting from the denudation of the peneplain. They have isolated cover of tertiary sediments and of pleistocene loess-loams. The penneplain is covered with weathering loams with poor remants of fossil weathering products. Steeper slopes are in the valleys and on the monadnocs crests. On the gentle denudational slopes are from place to place remnants of denudational plains as lowered and reduced remnants of the peneplain. There are also some structural plains on the tertiary deposits. Both great rivers of the country, Vltava and Lužnice, are bordered by erosional and aggradational terraces somewhere preserved only as recuded terraces with residual pebbles. From the level of 51-56 m above river level upwards there are denudated river terraces of pliocene and miocene age. The lower ones, the pleistocene river terraces form a system of 7 main levels, connected with the system of river terraces of the rivers Vltava and Labe in the middle Bohemia. This system of terraces of Vltava and Lužnice in the Týn country is given on the table on the page 324 and on the longitudinal diagramme-section, with the numerical and geometrical representation of the thickness of the terrace aggradational sediments with the bases and surfaces of the terraces, or only with the bases or surfaces of the denudated terrace-remnants.