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Neotectonics, volcanism, and landscape evolution in the western part of the Eger Rift

Andreas Peterek1, Ralf Schunk2, Claus-Dieter Reuther3
1 Department of Geomorphology, Bayreuth University, D-95440 Bayreuth & Czech-Bavarian Geopark / Bavarian Part, Marktplatz 1, D-92711 Parkstein
2 Geysir.info gGmbH, Konrad-Adenauer-Allee 40, 56626 Andernach
3 Claus-Dieter Reuther, Institute of Geology and Palaeontology, Bundesstraße 55, 20146 Hamburg

Key Note 3.2 in Endogene Prozesse (Neotektonik und Vulkanismus)

19.09.2012, 09:00-09:30, H6

The Eger (Ohře) Rift is the most spectacular neotectonic structure in the northern part of the Bohemian Massif. Plio-/Pleistocene to recent uplift and differential block movements exceed several hundreds of meters with the consequence of sharp morphotectonic structures. Our investigations have focused on the neotectonically active Cheb Basin which is located in the western part of the Cenozoic rift. In this area the rift is cross-cut by the more than 150 km long and in its northern part seismically active Mariánske Lázně Fault (MLF). This fault forms a prominent escarpment separating the subsiding Cheb Basin from the uplifted part of the Eger Rift (including the Eger Graben) to the east.

 

On the base of mapping of the morphotectonic features from the DEM, satellite and aerial images, and in the field, the compilation of the morphostratigraphic and the sedimentary record, we were enabled to reconstruct the neotectonic evolution of the Cheb Basin and to conclude some important implications for the late Pliocene to Recent crustal deformation of the western part of the Eger Rift.

 

The Eger Rift subsided during the late Oligocene and early Miocene. The rift evolution was accompanied by intense volcanism starting during the Eocene and lasting nearly to the present. Several phases of volcanic activity can be distinguished (pre-, syn-, and post-rift). Whilst the Eger Graben underwent mainly uplift and inversion since the mid-Miocene, subsidence of the Cheb Basin resumed during the late Pliocene development of the NNW-SSE striking Cheb-Domažlice Graben in response to intense activity along the MLF. During the Quaternary the Cheb and the Domažlice Graben were separated in conjunction with uplift of the southern shoulder of the Eger Rift. Ongoing tectonic activity along the MLF is manifested by earthquake swarms along its northern segment. The spectacular Plesna Fault which is accompanied by CO2-emanation centers and an up to 20 m high scarp is interpreted as a splay fault branching off from the MLF in the main earthquake region in the Nový Kostel area.

 

The crustal-scale MLF separates in the western part of the Eger Rift basement units that are characterised by different styles of neotectonic response to the late Pliocene to Recent stress field. This is one of the main reasons why the large-scale topography of the Bavarian part of the Eger Rift including the Cheb Basin strongly differs from the “classical” region of the Eger Graben.

 

References:

Peterek, A., Reuther, C.-D. & Schunk, R. (2011): Neotectonic evolution of the Cheb Basin (Northwesten Bohemia, Czech Republic) and its implications for late Pliocene to Recent deformation in the western part of the Eger Rift System. – Z. Geol. Wiss. 39: 335-365, Berlin.



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Letzte Änderung 13.07.2012