Reactivation of brittle tectonic structures in the Sudetic Marginal Fault vicinity (in north east of Bohemian Massif).
Abstrakt
The Bohemian massif came into existence during the variscan orogene. At that time a huge number of fault structures were caused by the orogene pressure.
Long years ago Alpine orogenesis has started close to the consolidated massif. A new pressure has reactivated part of the old variscan fault structures and caused new movements.
Thus so called neotectonic activity became into being. IRSM CAS documents the actual movements using long term GPS monitoring.
This paper is dealing with reactivated fault structures along one of the most important major fault structure in the north east part of the Bohemian massif - Sudetic Marginal Fault. The fault is 250 km long NW-SE structure on the boundary area of Bohemian massif.
Detailed geological research was carried out around a central part of the fault where the fault divides limestones on the west side and granites on the east side. An orientation of several hundred faults and joints was measured in nine quarries on both sides of the fault.
Kinematic indicators were observed as well. Typical set of joins (structures without kinematic indicators) in the area were found and defined.
There are E-W joints in the limestones and NE-SW in granites. The kinematic indicators pointed to the typical sets of faults in the area.
There are E-W and NW-SE faults in the limestones and NW-SE and NE-SW in granites. However there are a few joints in the direction of faults the sets are clear enough.
The results of geological research were compared with long term GPS monitoring in neighbourhood. It seems the results provided by both methods are in accordance.