Stress field evolution in a plate interior
Final Report Abstract
Central Europe comprises one of the most spectacular examples of intraplate shortening and rifting worldwide with contrasting tectonic regimes during the Mesozoic – Cenozoic time. The brittle deformation related to each tectonic regime is localized mainly along major fault zones and created complex fracture kinematics through time, which resulted in diverging interpretations on the number and succession of the causing events in the literature. This research reconciles the kinematic sequence and areal extent of the main tectonic events through fault-slip data analysis and paleostress reconstruction of a large area in the central German platform away from major fault zones. A new approach was developed for challenging data analysis in this platform setting with uniform lithology and structural style consisting of mostly flat-lying mid-Triassic strata. In this approach, the data were integrated into subsets of chronologically consistent kinematics, stress tensors computed through an iterative refining process, and the succession of events obtained through a chronological matrix analysis. This approach was cited in AGU's Tectonics journal among the successful methodologies in analysis of complex brittle deformation. The results revealed that only a few number of stress regimes could be traced regionally throughout the central German platform, which include a post-Triassic normal faulting event followed by a thrust faulting event in Late Cretaceous – Paleocene time, and two younger events of normal and strike-slip faulting. Radiometric dating attempts of syn-kinematic vein minerals yielded a Late Jurassic age for the first event. The interplay between these regional stress regimes and a network of pre-existing structures resulted in deviations in local stress fields, which depend on the orientation and mechanical stratigraphy of the preexisting structures. A rough integration of the stress fields with relative plate boundary velocity vectors revealed possible coincidences between the intra-plate and plate boundary kinematics through time. The substantiation of these coincidences remains for further synthesis through construction of time-constrained paleostress trajectory maps. Byproducts of the research include contribution in estimating reactivation potential of pre-existing fractures for the design of hot dry rock geothermal reservoir in the Mid-German Crystalline Rise, and contribution in the impact of magnetic rocks in compass measurements observed from Tertiary basalts in the Bohemian Cretaceous Basin.
Publications
- 2015. Analyse des Bruchflächeninventars in Grundgebirgsund Rotliegendaufschlüssen am Nordrand des Thüringer Waldes bei Ilmenau (Thüringen) hinsichtlich ihrer Versagenstendenz im rezenten Spannungsfeld. Beitr. Geol. Thüringen., N.F. 22, 137-152
Zinke, Ch., Navabpour, P. and Ustaszewski, K.
- 2017. Intraplate brittle deformation and states of paleostress constrained by fault kinematics in the central German platform. Tectonophysics, 694, 146-163
Navabpour, P., Malz, A., Kley, J., Siegburg, M., Kasch, N. and Ustaszewski, K.
(See online at https://doi.org/10.1016/j.tecto.2016.11.033) - Does intraplate brittle deformation indicate far-field stress signals? A case study of Central Europe. EGU General Assembly, Vienna, 23–28 April 2017
Navabpour, P., J. Kley, E. Le Breton, D.J.J. van Hinsbergen and K. Ustaszewski
- 2018. Fracture and bedding planes collected by compass from rock outcrops in the central German platform. Pangaea
Navabpour, P.
(See online at https://doi.org/10.1594/PANGAEA.893245) - Fault kinematics in the Thuringian Basin and the Flechtingen- Calvörde Block, Germany – The role of Jurassic extension tectonics in regional deformation patterns. EGU General Assembly, Vienna, 8–13 April 2018
Duschl, F., P. Navabpour, I. Dunkl and J. Kley
- What is the influence of pre-existing structures on regional intraplate tectonic stress fields? A case study of the central German platform. EGU General Assembly, Vienna, 8–13 April 2018
Navabpour, P., J. Kley and M. Richter
