Permo-Carboniferous and Cretaceous sediments cover the main tectonostratigraphic units of the crystalline basement in NE Bohemia. Within the activities of “Research Centre for Advanced remedial Technologies and Processes” the Czech Geological Survey revises the boreholes and geophysical investigations in the Bohemian Cretaceous Basin and adjacent areas. One part of the research is a compilation of pre-Cretaceous relief of the basement including the crystalline basement and Permo-Carboniferous relief. The digital elevation model uses all boreholes from the Czech Geological Survey-Geofond database, previous geophysical interpretation and the recent surface of the individual geological units defined from detailed geological mapping. The final model reflects well the evolution and recent position of several tectonic blocks and subsequent reprocessing of the information about basement rocks enables compilation of the ´solid´ geological map., Zuzana Skácelová, Bedřich Mlčoch and Zuzana Tasáryová., and Obsahuje bibliografii
The paper presents the results of monitoring study undertaken during the period 2008 - 2010. The study recorded the displacement of tectonic structures in the Strašín Cave (SW Bohemian Massif). The derived results were compared, among others, with data recorded over the same time period across the Bohemian Massif in the EUTecNet (tectonic displacement monitoring net - see www.tecnet.cz), which is managed by IRSM ASCR. The rate of recorded displacement is mostly in order of hundredths mm/year with maximal value recorded in vertical component at site Strašín 2, about 0,16 mm/2,5 years. Whilst recorded displacement can indicate blocks subsidence into the cave empty space, the periods when displacement occurred correspond to periods of increased movement activity recorded for example at the opposite side of the Bohemian Massif, along the Sudetic Marginal Fault. Moreover, both periods are simultaneous with extraordinary earthquakes that affected western and southern part of the Bohemian Massif in 2008 and 2009., Josef Stemberk and Filip Hartvich., and Obsahuje bibliografii
To investigate the geodynamic pattern of the Bohemian Massif in Central Europe, the GEONAS network of permanent GNSS stations was established. It now consists of 18 stations, recorded both the NAVSTAR and GLONASS positional signals; they are located along the tectonic zones of the Massif in order to monitor any movement activities. Yet other stations are still planned to be built, and some recent stations are to be moved within these active areas to increase their local distribution density. The GNSS data are processed by the use of Bernese GPS software 5.0. The time series of station positions give fundamental information for both regional and local geodynamic studies. The GEONAS network covers an area of 400 by 220 km, and it allows the effects of dynamic processes going on inside the Earth’s crust, as well as the upper lithosphere to be monitored. A few examples of geodynamic interpretations are presented here., Vladimír Schenk, Zdeňka Schenková, Milada Cajthamlová and Zdeněk Fučík., and Obsahuje bibliografii
During 2007 and 2008 there were realized gravity measurements using the relative gravimeter Scintrex CG-5 on sites of geodynamic networks HIGHLANDS and fundamental gravity sites of the Czech Gravity Reference Network. The gravity measurements were concentrated on monitoring the long-term trends of gravity acceleration changes among individual measurement sites. The methodology of measurement was optimized and preliminary time changes in gravity differences among sites were determined., Roman Kujal, Vladimír Schenk and Zdeňka Schenková., and Obsahuje bibliografii
A brittle tectonic study has been carried out in the crystalline limestone and granite quarries near Vápenná village in the Rychlebské hory Mts. in the NE part of the Bohemian Massif. The quarries are situated along the Sudetic Marginal fault zone - the most important tectonic structure of the area. At the lo cality, the Sudetic Marginal fault separates Devonian crystalline limestones of the Branná group and Paleozoic granites of the Žulová pluton. Hundreds of measurements of joints and small-scale faults were taken in three limestone quarries on the west side of the fault. Kinematic indicators were observed as well. Equivalent measurements and observations have been performed on the fault east side in several small granite quarries. In the limestones three sets of fault have been identified (the W-E subvertical, the Sudetic NW-SE falling 45° to NE and the N-S falling 75° to W). The W-E direction of faults is the most importa nt direction there. There are two sets of faults in the granites (the subvertical Moravo-Silesian NE-SW and the Sudetic NW-SE). The NE-SW direc tion is dominant. There are almost none subhorizontal faults in the studied area., Lucie Nováková., and Obsahuje bibliografické odkazy
The WEST SUDETEN geodynamic network consists of 11 sites on that five annual GPS epoch measurements in period of 2001-2005 were carried out. The 48-hour epoch data linked to 4 permanent EPN station observations created reasonable GPS data base for a preliminary evaluation of site movement velocities. General movement pattern over the network has been obtained and some regional and local movement relations among network sites were observed and discussed. The whole region under study displays three areas with relatively different movement trends. The northern area, i.e. the Krkonoše Mts. structural block, displays pronounce motion to the NW with respect to the central area that involves the Permian piedmont of the Krkonoše Mts. covered in its southern part by the Cretaceous sediments. Besides, conspicuous dextral movement along the Železné hory Mts. fault zone was detected too., Vladimír Schenk, Zdeňka Schenková, Milada Grácová and Pavel Kottnauer., and Obsahuje bibliografii
Three year monitoring of micro-displacements on four tectonic fracture planes in a tunnel driven by a milling cutter into granitoids of Bohemian Massif revealed micro-movements that develop in certain trends and impulses. Two investigated fractures are of the Krušné Hory Mts. orientation (NE - SW), other two of Sudeten orientation (NW - SE). These have been found the two prevailing fracture orientations in the massif. Results from all the four fractures indicate trends in overfaulting of southern blocks over the northern ones and a stress state model characteristic of approximate N-S compression with overthrust vergence to N. Besides, some impulses were indicated with abrupt occurrence that dominates the development of movements. The first most significant impulse occurred by the end of the year 2004, the second one at the break of 2005/6. The coincidence of the impulses with earthquake events is discussed., Josef Stemberk and Blahoslav Košťák., and Obsahuje bibliografii
To investigate recent crustal movements between northern and southern parts of Moravo-Silesian region of the Bohemian Massif and to find their relation to movements of structure blocks of Moldanubicum, it was decided to establish a regional geodynamic network HIGHLANDS. Seven sites for monitoring GPS signals were built with respect of geological and geophysical materials in the southern area of the Českomoravská vysočina Highlands. So far two epoch 48-hours GPS measurements have been performed in 2005 and 2006 with Ashtech receivers and antennas. GPS monitored data were processed by the Bernese software v. 5.0. The rather preliminary site movements were assessed and discussed from the viewpoint of recent geodynamic motions., Zdeňka Schenková, Vladimír Schenk, František Mantlík and Milada Grácová., and Obsahuje bibliografické odkazy
A reliability of site movement assessments determined from GPS data monitored during eight two-day epoch measurements on the regional geodynamic EAST SUDETEN network (the Bohemian Massif, Central Europe) is discussed in details. Statistical tests of site positions processed by the BERNESE GPS software, their linear approximations for site movement velocity assessments and an establishment of probabilistic thresholds for reliability of the GPS data for regional geodynamic studies are delivered. The thresholds define necessary observation periods for annual epoch measurements performed on the networks with aim to obtain reliable movement estimates for geodynamic studies., Vladimír Schenk, Zdeňka Schenková, Jaroslaw Bosy and Bernard Kontny., and Obsahuje bibliografii
Rock landforms in the Sokolský hřbet (ridge) and the adjacent Žulovská pahorkatina (hilly land) have been analysed through detailed field mapping at a scale of 1:10,000; subsequently the spatial distribution of these features was analysed using a DEM within a GIS framework. Particular attention was focused upon the shape of the rock landforms, their arrangement, the aspect of their walls, and their topographic position within the two adjacent geomorphological units. Rock landforms in the Sokolský hřbet include frost-riven cliffs, isolated residual rockforms, and blockfields in metamorphic rocks. In contrast, rock landforms in the Žulovská pahorkatina include rock steps and numerous tors exposed from the basal weathering surface. The Sokolský hřbet has been interpreted as a neotectonically uplifted mountainous region; the rock landforms described here are thought to have formed under periglacial conditions during cold periods in the Pleistocene, whilst the extensive granitoid block accumulations developed on marginal fault scarps are thought to result from the exposure of intensively disintegrated rocks due to uplift. Žulovská pahorkatina has been interpreted as a remodelled stripped etch surface, which has been twice glaciated during the Middle Pleistocene. The rock landforms in both units appear to be structurally and lithologically controlled; moreover, various shapes of granite rock landforms are controlled by various types of jointing and parting. The clear differences recognised in both the rock landforms and overall morphology reflects the considerable disparity associated with relief development between two adjacent morphostructural units; such variability provides evidence for a long polygenetic history within the entire study area., Petra Štěpančíková and Matt Rowberry., and Obsahuje bibliografii