Stress field changes in Central Europe from Late Miocene to Quaternary
as determined from volcanic rocks in the Bohemian Massif
Abstract
This work presents the results of a paleostress investigation in dated
Mio-Pliocene volcanic rocks in the vicinity of the town of Lądek Zdrój
in the Rychlebské hory Mts., as a part of the central Sudetic Mts. in
the NE Bohemian Massif. Six different paleostress field regimes from the
Late Miocene to Quaternary were distinguished. Each stress regime is
characterized by the orientation of the principal parameters and is
discussed in relation to the known paleostress regimes within the
surrounding regions of the Sudetic Mts., Fore-Sudetic block, and
European Alpine foreland in Central Europe. The results show switching
of tectonic phases with dominant compression, transtension or extension.
Moreover, the orientation of theoretical planes with maximum shear
stress and with a high tendency to dilate for individual paleostress
regimes is defined and compared with the orientation of known faults
within the study area suggesting their possible kinematics. The timing
of the derived regimes is determined more accurately and is in good
accordance with the data reported from different regions in Central
Europe, which suggests their broader validity. In addition, one event or
shorter events interrupting the main Plio-Quaternary extensional regime
and one differently oriented Plio-Quaternary extension regime were
discovered and constrained based on several dated phases of the
volcanism of the faulted rocks.