František Marko

Plate-tectonic Evolution and Paleogeography of the Circum-Carpathian Region

Sixteen time interval maps were constructed that depict the latest Precambrian to Neogene plate-tectonic configuration, paleogeography, and lithofacies of the circum-Carpathian area. The plate-tectonic model used was based on PLATES and PALEOMAP software. The supercontinent Pannotia was assembled during the latest Precambrian as a result of the Pan-African and Cadomian orogenies. All Precambrian terranes in the circum-Carpathian realm belonged to the supercontinent Pannotia, which, during the latest Precambrian–earliest Cambrian, was divided into Gondwana, Laurentia, and Baltica. The split of Gondwana during the Paleozoic caused the origin of the Avalonian and then Gothic terranes. The subsequent collision of these terranes with Baltica was expressed in the Caledonian and Hercynian orogenies. The terrane collision was followed by the collision between Gondwana and the amalgamation of Baltica and Laurentia known as Laurussia. The basement of most of the plates, which was an important factor in the Mesozoic–Cenozoic evolution of the circum-Carpathian area, was formed during the late Paleozoic collisional events. The older Cadomian and Caledonian basement elements experienced Hercynian tectonothermal overprint. The Mesozoic rifting events resulted in the origin of oceanic-type basins like Meliata and Pieniny along the northern margin of the Tethys. The separation of Eurasia from Gondwana resulted in the formation of the Ligurian–Penninic–Pieniny Ocean as a continuation of the Central Atlantic Ocean and as part of the Pangean breakup tectonic system. During the Late Jurassic–Early Cretaceous, the Outer Carpathian rift developed. The latest Cretaceous–earliest Paleocene was the time of the closure of the Pieniny Ocean. The Adria–Alcapa terranes continued their northward movement during the Eocene–early Miocene. Their oblique collision with the North European plate led to the development of the accretionary wedge of the Outer Carpathians and foreland basin. The northward movement of the Alpine segment of the Carpathian–Alpine orogen has been stopped because of the collision with the Bohemian Massif. At the same time, the extruded Carpatho-Pannonian units were pushed to the open space toward the bay of weak crust filled up by the Outer Carpathian flysch sediments. The separation of the Carpatho-Pannonian segment from the Alpine one and its propagation to the north were related to the development of the north–south dextral strike-slip faults. The formation of the Western Carpathian thrusts was completed by the Miocene. The thrust front was still progressing eastward in the Eastern Carpathians. The Carpathian loop, including the Pieniny Klippen structure, was formed. The Neogene evolution of the Carpathians resulted also in the formation of the genetically different sedimentary basins. The various basins were formed because of the lithospheric extension, flexure, and strike-slip-related processes.

The East Slovakian Basin — A complex back-arc basin

Abstract The East Slovakian Basin is situated on the junction of the Western and Eastern Carpathians. It is superimposed on the frontal part of the Carpathian internides, behind the Tertiary accretionary wedge of the Carpathian externides represented by the Flysch Belt. The development of the basin was controlled by the collision of the Carpathian orogen with the European platform and later by crustal extension and thermal subsidence in the Pannonian domain. The Early Miocene basin evolution was dominantly influenced by the collisional process. During the Eggenburgian, a narrow relic fore-arc basin was formed along the suture between the Carpathian internides and externides, nowadays represented by the Pieniny Klippen Belt. The compressive regime resulted in the disintegration of the basin, followed by the Ottnangian uplift and the development of a deep-seated dextral strike-slip fault zone. During the Karpatian, the central part of the basin was opened by a pull-apart mechanism, which stepwise changed to extensional basin evolution during the Lower and Middle Badenian. From the Upper Badenian on, the basin development was influenced by crustal extension associated with updoming of the mantle masses. A back-arc basin developed. During the Late Miocene, the East Slovakian Basin became a peripheral part of the Pannonian Basin System, where the sedimentation was controlled by the thermal subsidence at that time. During the Pontian and Pliocene a NE-SW-oriented compression was indicated.

Tertiary extension development and extension/compression interplay in the West Carpathian mountain belt

Abstract This paper describes palaeostresses calculated from fault-striae data, the inferred palaeostrain patterns and determines the inter-relation of the compression and extension during the Tertiary development of the West Carpathians. The calculated stress and inferred strain patterns for the Palaeogene–Burdigalian indicate that the ancestral West Carpathians formed a more-or-less straight orogenic belt. This belt underwent contraction and uplift in its narrow frontal zone, stretching along its strike during the Paleocene–Chattian, and regional contraction and uplift during the Chattian–Burdigalian. The strain/stress pattern is similar to the collision-related pattern known from the Eastern Alps for the Paleocene–Burdigalian. During the Burdigalian–Tortonian, the calculated and inferred West Carpathian stress and strain patterns indicate narrow frontal contractional and lateral sinistral transpressional zones in the orogenic front and broad extensional and dextral transtensional zones in the orogenic interior. The stress/strain pattern is similar to the subduction-related pattern known from areas such as the Hellenic or Sunda/Banda Arcs.

Pliocene to Quaternary tectonics in the Horná Nitra Depression (Western Carpathians)

Pliocene to Quaternary tectonics in the Horná Nitra Depression (Western Carpathians) The Horná Nitra Depression is an Upper Miocene-Quaternary intramontane sedimentary basin. This N-S elongated half-graben structure is rimmed from the west by the marginal Malá Magura fault which is the most distinctive fault in the Horná Nitra Depression, traditionally considered as an active fault during the neotectonic phase. This dislocation is attended by contrasting landforms and their parameters. The low S-index of about 1.10, at least two generations of well-preserved faceted slopes along this fault, and longitudinal river valley profiles point to the presence of a low-destructed actual mountain front line, which is typical for the Quaternary active fault systems. Comparison with known normal fault slip rates in the world makes it possible to set an approximate vertical slip rate between 0.3-1.1 m · kyr-1. The present-day fault activity is considered to be normal, steeply dipping towards the east according to structural and geophysical data. The NNW-SSE present-day tectonic maximum horizontal compressional stress SH and perpendicular minimum horizontal compressional stress Sh was estimated in the Horná Nitra region. The Quaternary activity of the Malá Magura fault is characterized by irregular movement. Two stages of important tectonic activity along the fault were distinguished. The first stage was dated to the Early Pleistocene. The second stage of tectonic activity can by dated to the Late Pleistocene and Holocene. The Malá Magura fault is permeable for gases because the soil atmosphere above the ca. 150 meters wide fault zone contains increased contents of methane and radon.

Late Quaternary fault activity in the Western Carpathians: evidence from the Vikartovce Fault (Slovakia)

Late Quaternary fault activity in the Western Carpathians: evidence from the Vikartovce Fault (Slovakia) The Cenozoic structure of the Western Carpathians is strongly controlled by faults. The E-W striking Vikartovce fault is one of the most distinctive dislocations in the region, evident by its geological structure and terrain morphology. This feature has been assumed to be a Quaternary reactivated fault according to many attributes such as its perfect linearity, faceted slopes, the distribution of travertines along the fault, and also its apparent prominent influence on the drainage network. The neotectonic character of the fault is documented herein by morphotectonic studies, longitudinal and transverse valley profile analyses, terrace system analysis, and mountain front sinuosity. Late Pleistocene activity of the Vikartovce fault is now proven by luminescence dating of fault-cut and uplifted alluvial sediments, presently located on the crest of the tilted block. These sediments must slightly pre-date the age of river redirection. Considering the results of both luminescence dating and palynological analyses, the change of river course probably occurred during the final phase of the Riss Glaciation (135 ± 14 ka). The normal displacement along the fault during the Late Quaternary has been estimated to about 105-135 m, resulting in an average slip rate of at least 0.8-1.0 mm · yr-1. The present results identify the Vikartovce fault as one of the youngest active faults in the Central Western Carpathians.

Neogene history of intramontane basins in the western part of the Carpathians

Neogene collision of the Carpathians with the European Platform resulted in flysch nappes overthrust in frontal part of the orogene. Tectonic activation of the Paleoalpine-consolidated Centrai Western Carpathians led to modification of their structural pattern. Axis of the main compression rotated from NW-SE to NE-SW. Thrust-reverse faults and ENE-WSW dextral strike- slips were dominant in the Lower Miocene. Movement of the Western Carpathians north-eastward during the Middle and Upper Miocene caused activation of ENE-WSW sinistrai strike-slips and NE-SW normai faults. Pliocene regional extension was manifested mainly by NE-SW normai faults which controlled the sedimentation and form of the basins.

Radon measurements in an area of tectonic zone: A case study in Central Slovakia

General overviews of the spatial distribution of radon and other natural radionuclides in the geological basement as commonly presented on regional or country maps tend to offer a low density of information, insufficient for gaining relevant knowledge of the environmental impact, especially in the areas of tectonic zones often assumed to be radon prone and therefore dangerous for the human population. An additional survey, employing radon measurements in soil and indoor air, was carried out seeking to provide a more detailed characterization of the expressive fault zone of the Malá Magura in the Horná Nitra region of Central Slovakia. Eventually, the results of soil 222Rn volume activity measurements along two short profiles crossing the assumed fault line did not reveal any indication of active nature of local tectonics, but merely pointed to an existence of a zone of contact between different types of rocks. The results of indoor radon measurements in dwellings of two villages lying on the studied fault showed values that were lower than those commonly observed on the Slovak territory, ruling out any negative health impact on population. Nevertheless, in order to add new findings to an already well established study of geological structure of the region, the indoor radon data collected through a previous survey require a further analysis.