The post-Variscan Paleostress History of the Central European Basin System

• Applicant: Professorin Dr. Magdalena Scheck-Wenderoth
• Subject Area: Palaeontology
• Term: from 2005 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5448536

The main scientific objective of the project is to investigate the paleo stress fields whichcontrolled the post-Variscan evolution of the Central European Basin System (CEBS).Therefore, field studies are carried out in the marginal areas of the CEBS where LatePalaeozoic and Mesozoic rocks of the basin fill are present in outcrops. These rocks bear theimprints of several deformation phases that affected the basin system since the LatestCarboniferous. In the course of the project a detailed structural analysis is performed at keyareas along the southern and northern margins of the CEBS where outcrops of lithologies withfavourable conservation conditions of kinematic indicators are present. In detail,measurements of fault slip data will be carried out at outcrops of the Permian-Mesozoicsuccession at different segments of the southern margin of the CEBS. This will becomplemented by equivalent field studies at outcrops on Bornholm as key area of the northernmargin of the CEBS and at different sites on the Danish mainland as key sites for UpperCretaceous rocks on the Ringkobing Fyn High. Subsequently, the orientation of the principalstress direction through time is calculated by fault-slip data inversion to evaluate thedistribution of regional paleo stress pattern. The displacement vector on fault planes recordedby striae is considered to correspond to the direction and sense of the shearstress tensor.Based on this assumption, the deviatoric stress tensor is calculated using quantitativecomputer-aided inversion methods. The results are obtained in terms of a reduced stresstensor, consisting of (1) orientations of the three principal stresses CT-J, 02 and 0. In the case of polyphase tectonics, the chronology of successive events is deducedand the total fault population from each site is qualitatively divided into different subsets,each being consistent with one specific stress regime. Since the stratigraphy and evolution ofthe CEBS are well known, temporal and spatial correlations of paleo stress orientations arepossible. A network of local determinations related to each tectonic event will allow thereconstruction of the regional paleo stress patterns which finally will be evaluated withrespect to the control they exerted on the structural evolution of the entire CEBS. Theproposed study will complement the outcomes of the project "Mesozoic fault systems".

• DFG Programme: Priority Programmes
• Subproject of: SPP 1135: Dynamics of Sedimentary Systems under Varying Stress Regimes: The Example of the Central European Basin System
• International Connection: Poland
• Participating Persons: Dr. Stanislaw Mazur; Professor Dr. Klaus Reicherter