Morphostratigraphy of river terraces in the Eger valley (Czechia) focused on the Smrciny Mountains, the Chebska panev Basin and the Sokolovska panev Basin
Abstract
The Eger (Ohre) River terraces originated in varied morphotectonic and climate-morphogenetic conditions that existed during the late Cenozoic evolution of the western part of the Bohemian Massif. In the area between the Smrciny Mountains and the Sokolovska parley Basin, these levels of the Eger River terrace system were identified (Table 1): the Pliocene terrace niveau B, the Cheb terrace (I), the Hradiste terrace (II), the Chvojecna terrace (III), Jindrichov terrace (IV), Nebanice terrace (V), Chocovice terrace (VI), Chotikov Terrace (VII) and the recent flood plain (N).
It was determined to be a morphostratigraphical system of 7 river terraces of Quaternary age. Older levels of fluvial sediments, occupying a still higher morphological position in the area between the Smrciny Mountains and the Sokolovska parley Basin, have been classified to the Pliocene.
A comparison of terrace flights in the longitudinal profile of the Eger River between the Smrciny Mountains and the Doupovske hory Mountains indicated that the Cheb terrace (I) in the Smrciny Mountains is tectonically uplifted around 10 m in comparison with its level in the Chebska parley Basin. In the Chlumsky prah Horst area, the oldest Pleistocene terraces, which originated during the Tiglian stage, were uplifted by approximately 15 m.
The Chebska parley Basin originated at the intersection of the Eger rift and the Cheb-Domailice fault zone and its river network is incised ca 40 m into the planation surfaces of the sedimentary basin. Both volcanic processes and frequent seismic activity in the region are associated with the Late Cenozoic tectonic movements.
According to the current stratigraphical scheme of the Quaternary, the Eger terrace system was formed mostly by the Pleistocene (Table 2) during the Tiglian to the Weichselian stages.