Central Western Carpathians Research Articles

Depositional conditions, wildfires, maturity, and hydrocarbon potential evaluation of Central Carpathian Paleogene Basin based on integrative approach from Orava Basin

Central Carpathian Paleogene Basin (CCPB, Central Western Carpathians) comprises mainly Oligocene clastic autochthonous age-equivalents of the widely known Menilite shale formation from the Outer Carpathians. However, little is known about the paleoenvironment and its subsequent changes during the basin's evolution. Furthermore, the available hydrocarbon potential data are based on anachronous methods and are not investigated on the sub-basin level. Gas chromatography-mass spectrometry (GC–MS) analyses supported by Rock-Eval data along with petrographic measurements enabled us to identify and document the paleoenvironmental evolution of the Orava sub-basin (NW remnant of CCPB). Thermal maturity based on vitrinite reflectance, 22S/(22S + 22R) homohopane ratio and 20S/(20S + 20R) sterane ratio increases from N to S and from Upper to Lower Oligocene. In the least mature samples ββ-hopanes, hopenes, and oleanenes are present, whereas in the most mature deposits less thermally stable compounds dissapeared. This maturation trend is shown also by the Rock-Eval data. Terrestrial organic matter input is documented by the predominance of III- and II/III-type of kerogen and the occurrence of several biomarkers, such as 3,3,7-trimethyl-1,2,3,4-tetrahydrochrysene, cadalene, retene, and perylene. The significant contribution of polycyclic aromatic hydrocarbons (PAHs) may be linked with wildfire-related land degradation and following runoff to the basin. Based on the measured fusinite reflectance values the wildfire types could range from hotter crown fires to colder surface fires. Depositional conditions in Lower Oligocene units are characterized by intermittent euxinia, as derived from small (<5 μm) pyrite framboid diameters and the presence of isorenieratane. Subsequently, a change of conditions to oxic/dysoxic in younger units is observed, and the input of terrestrial organic matter increased.

Tracing the latest Jurassic–earliest Cretaceous paleoenvironment evolution in swell carbonate facies: a case study of the High-Tatric succession (Central Western Carpathians, Tatra Mts, Poland)

This paper presents an interpretation of sedimentologic, paleomagnetic, and geochemical data collected in the Upper Kimmeridgian–Valanginian carbonates of the Giewont series (Giewont and Mały Giewont sections, High-Tatric succession, Western Tatra Mountains, Poland). The studied succession provides insight into the sedimentary conditions prevailing in the South Tatric Ridge (Tatricum), a submarine elevation located between the Zliechov Basin (Fatricum) and the Vahic (=South Penninic) Ocean. The sedimentary sequence includes micrites, pseudonodular limestones, cyanoid packstones, lithoclastic packstone, and encrinites. The results are discussed with regards to their significance for detrital input, paleoclimate, and paleoproductivity, which in turn are considered in the context of both local and regional paleoenvironmental trends and events. The greatest depositional depths during the latest Kimmeridgian–earliest Tithonian are documented by the occurrence of pseudonodular limestones. A Tithonian shallowing trend is demonstrated via the increasing size and roundness of cyanoids, while the final (?)emergence and erosion in the South Tatric Ridge is documented by earliest Cretaceous disconformities. This process might have been related to both falling sea-level during the major eustatic regressive cycle and tectonic uplift caused by the mutually related (re)activation in the Neotethyan Collision Belt and rifting in the Ligurian-Penninic-Vahic Oceans. The highest lithogenic influx (although still low; max 0.5% of Al content) during the Late Kimmeridgian is considered as associated with relatively humid climate conditions, whereas a subsequent decreasing trend is thought to result from aridification during the latest Kimmeridgian–earliest Tithonian. Ultimately, deposition in the High-Tatric zone was affected by both large-scale environmental perturbations characteristic of the latest Jurassic (climate changes, variations in seawater pH, monsoonal upwelling, lithogenic input, etc.), as well as local sedimentary controls, predominantly the oxygenation state of bottom waters and tectonic movements. Supplementary Material 1

Stratigraphically significant, sporadic Early Cretaceous ammonites in Butkov Quarry (Central Western Carpathians, Slovakia)

Butkov Quarry provides the best exposed stratigraphic sequence of marly limestones with Early Cretaceous ammonites in the Manín Nappe of the Central Western Carpathians. The presented paper deals with the sporadically occurring zonal ammonites, or ammonites of guiding character, from the Lower Valanginian to Upper Hauterivian. Sixteen species are taxonomically elaborated here in detail. More attention is given to the basic taxonomy of the Subfamily Crioceratitinae Gill, 1871. The species described here, like most of the previously published species from Butkov Quarry, are representatives of the Mediterranean bioprovince and are close to the ammonite association from the Vocontian Basin.

Application of the authigenic 10Be/9Be dating to constrain the age of a long-lived lake and its regression in an isolated intermontane basin: The case of Late Miocene Lake Turiec, Western Carpathians

The depositional record of intermontane basins provides a valuable archive of the temporal evolution of orogenic belts; their common isolated nature may, however, hinder the efficient usage of standard approaches to constrain the age of a basin fill. In this paper the authigenic 10Be/9Be dating method is employed and tested to construct an age model of the existence and regression of Lake Turiec, which appeared during the Late Miocene in the intermontane Turiec Basin, Central Western Carpathians (Central Europe). The initial authigenic 10Be/9Be ratio, essential for the dating method, was analyzed on five sites of the Pleistocene-Holocene age, and back-calculation of the paleo-initial ratio was performed using lacustrine succession dated by magnetostratigraphy. Noteworthy, the initial ratio appears to be affected mainly by (post)depositional settings, and not by different provenance of the analyzed sediment. The sedimentological analysis of the Upper Miocene outcrops allowed the definition of the facies associations of an alluvial fan, a braided river, a fan delta and an open lake. The distribution of facies associations in the basin fill implies an increase in sediment supply to accommodation rate ratio due to the replacement of the open lake environment by the interconnected alluvial fan-braided river-fan delta system. Authigenic 10Be/9Be dating yielded ages of the lacustrine succession reaching ∼10.7–7.8 Ma, while the age of the fan delta succession, considered as the timing of the regression, was established to ∼6.7 Ma. The deposition of alluvial fans dominated the basin after the regression of the lake, possibly up to ∼4.0 Ma. The abrupt increase in sediment supply to the accommodation ratio at ∼6.7 Ma was caused by the uplift of the Malá Fatra Mts. at the western margin of the Turiec Basin, which had previously formed a moderate topography. The timing of this process generally coincides with the overall decrease in accommodation rates in the region due to the inversion of the Pannonian Basin System. The endorheic character of the basin before ∼6.7 Ma prevented the transport of the sediment denudated from the recently most uplifted parts of the Western Carpathians and carried towards the Pannonian Basin System, while the present-day source-to-sink system could only be formed later. This implies a low sediment supply and restricted denudation rate not only from the morphostructures surrounding the basin, but also from the Tatra Mts. and Nízke Tatry Mts. during the period ∼10.7–6.7 Ma. The research supports the suitability of intermontane basins for authigenic 10Be/9Be dating in a setting of high accommodation rates and limited redeposition of older muddy sediment. However, a special attention has to be paid to the depositional settings during determination of initial 10Be/9Be ratios.

Troglomorphic adaptations on the northern European frontier: the phylogeny of the cave Pseudosinella (Hexapoda, Collembola) in the Western Carpathians

IntroductionUsing an integrative taxonomic approach, we investigated the morphological and molecular characters to identify the species of the genus Pseudosinella occurring in caves of the Western Carpathians and to clarify their phylogenetic relationships. Based on morphological characters, we hypothesized that Pseudosinella aggtelekiensis (Stach, 1929) and Pseudosinella paclti (Rusek, 1961) originated from different phyletic lineages.MethodsWe used the barcoding fragment of the mtDNA COI gene from 87 individuals from 16 caves to reconstruct the phylogenetic history of the genus Pseudosinella.ResultsThe molecular phylogenetic tree revealed two distinct species groups with allopatric distributions. The first group consisted of P. aggtelekiensis populations from the Slovak Karst and three undescribed species from fragmented and isolated karst areas in southeastern Slovakia. The second group, P. paclti populations in the Central Western Carpathians, was merged. This group included Pseudosinellamuranensis, a new species taxonomically described in this work. It is characterized by highly developed troglomorphic features and is restricted to a small karst area, the Muranska planina Plateau. The phylogeny of the genus Pseudosinella from the caves of the Western Carpathians revealed a Miocene diversification. According to molecular calibration, the two distinct Pseudosinella lineages were separated in the Middle Miocene, about 14.51 Mya, followed by further diversification in the P. paclti lineage 10.89 Mya and in the P. aggtelekiensis lineage 11.14 Mya.DiscussionThis phylogeny is consistent with the uplift of Triassic limestones during the early formation of the Western Carpathians in the Paratethys region and the initial development of caves during this period. The study provides further important evidence that the Western Carpathians played a significant role as an independent speciation center of the obligate cave fauna in Europe.

Provenance of quartz debris in the Central Western Carpathians at the end of the Triassic, as indicated by cathodoluminescence colours

Lithic fragments including quartz grains occur infrequently in the shallow-marine limestone sequence of the Fatra Formation deposited in the tensional intra-shelf depression of the Central Western Carpathians during the Rhaetian. Nevertheless, their study can bring data answering questions of sources, palaeogeodynamic arrangement, and processes at the end of the Triassic. In this study, we examined optically the cathodoluminescence (CL) colours of single quartz grains from the Kardolína section (Tatra Mts, Slovakia). These colours reveal a dominance of grains derived from regionally metamorphosed and plutonic rocks. Grains of hydrothermal and pegmatite origin are less frequent. Some of the quartz grains show recycled cement rims suggesting at least a second cycle origin. This sedimentary basin was situated near to the passive margin formed by the Variscan consolidated terrains of the Vindelician Highlands. Our study of the CL colours of quartz grains contributes to the elucidation of the nature of the rocks of the vanished Vindelician mountain belt.

Latest Hauterivian foraminiferal and calcareous nannofossil assemblages and bioevents from the Pseudothurmannia beds (Central Western Carpathians, Slovakia): A prelude to the Faraoni event

A diverse and abundant assemblage of deep-water agglutinated foraminifera (DWAF) has been recovered from an uppermost Hauterivian ammonite-rich horizon (Pseudothurmannia ohmi Biozone) from the Central Western Carpathians. The section records the last occurrence of the calcareous nannofossil species Litraphidites bollii (Thierstein) preceding the Faraoni anoxic level. Various morphogroups of agglutinated foraminifera show changes in response to trophic regime shift and decreasing oxygenation of the bottom and pore waters in a relatively short time-series. The DWAF data were compared with calcareous nannofossil assemblages and foraminifera analysed from thin sections (calcareous benthic and planktonic foraminifera). Four ecozones were identified, each with a specific taxonomic composition of foraminiferal assemblages. The zone-to-zone changes include fluctuations in the richness and relative abundance of morphogroups and planktonic foraminifera, and dwarfism in certain groups of foraminifera.

Burial and thermal history of the eastern transform boundary of the central western carpathians based on 1D basin modeling

This paper represents the first data on the thermal and burial history of Mesozoic and Cenozoic sedimentary rocks in the Maruszyna IG-1 deep borehole from the transpressional shear zone of the Western Carpathians. Representative, organic-rich mudstone and claystone samples were selected to determine thermal maturity using mean random vitrinite reflectance (Ro) and thermal alteration index (TAI) data. The reconstruction of the thermal history of fold-and-thrust units was carried out using 1D modeling. This study uniquely distinguishes various thermal maturity levels in the deep profile determined by strata repetition, different absorption of clay and carbonate mineral settings and structural thermal changes in humic particles and palynomorphs. Reflectance of autochthonous vitrinite varies from 0.77 to 1.95% indicating thermally mature to overmature organic matter. Different subsidence-uplift models were tested during modeling in order to find a plausible scenario of tectonic development and heat flow history. The thermal maturity of the individual thrust sheets was modeled separately allowing their individual thermal histories to be investigated before and after the main and final thrusting phase. The best-calibrated scenario assumes a low paleo heat flow ranging from 45 to 54 mW.m-2, affecting the eastern part of the Western Carpathians. The maximum temperature which lead to maturation of the organic matter seems to be related to its successive burial during Cretaceous due to compressional deformation. Individual thrust sheets reached thermal maturity prior to the final thrusting phase. The overthrust was accompanied by 3000–4000 m burial/erosion resulting in different thermal pathways during wedge growth.

Hydrothermal ore mineralization from the Polish part of the Tatra Mts., Central Western Carpathians

Several areas with hydrothermal ore mineralization are present in the Polish part of the Western Tatra Mts. Massive and disseminated sulfides, mainly minerals from the tetrahedrite group and chalcopyrite, fill quartz veins accompanied by siderite, dolomite and baryte – many of these were mined between the 16th and 18th century. This paper presents information on the mineralogy of the common sulfides and the preliminary studies of both the isotopic composition of sulfur in tetrahedrite as well as the origin of hydrothermal fluids. The most common primary sulfide minerals in the ores are tetrahedrite-(Zn) and tetrahedrite-(Fe) corresponding to Zn ranges from 1.83 to 5.87 wt.% (0.47–1.44 apfu), and Fe from 1.63 to 5.05 wt.% (0.48–1.52 apfu). The substitution of As for Sb shows maximum As content of 7.25 wt.% (1.588 apfu) which corresponds to the Sb/(Sb+As) = 0.60. Both varieties show substitutions of Bi and Hg, up 0.6 wt.% (0.049 apfu) and 0.96 wt.% (0.081 apfu), respectively, and content of trace elements: Co (max. 976 ppm), Cd (max. 735 ppm), In (max. 14 ppm). Chalcopyrite, pyrite, and galena show compositions close to the ideal formula. Differences in the content of trace elements in the studied tetrahedrite and chalcopyrite were explained by element partitioning between these minerals. The distributions of In, Ga and Sn in the studied minerals indicate that the mineralization was formed at low temperature and pressure. The homogenization temperature of the primary inclusions in quartz in the range of 120–174°C indicate the origin of mineralization in low-temperature stage from low salinity fluids (up to 17.92 wt.% NaCl eq.). Stable δ34S isotopes in minerals of the tetrahedrite group suggest that the igneous fluids might be one of the sources from which ores were crystallized.

On imperfectly known Hauterivian representatives of the families Holcodiscidae Spath, 1923 and Barremitidae Breskovski, 1977 in Butkov Quarry (Central Western Carpathians, Slovakia)

In Butkov Quarry, ammonites of the families Holcodiscidae Spath, 1923 and Barremitidae Breskovski, 1977 occur in the pelagic Lower Cretaceous pelagic deposits of the Manín Unit. This contribution discusses the taxonomy of both families and presents their distribution in the layered sequences of the quarry. The genus Spitidiscus Kilian, 1910 classified as a member of the Superfamily Perisphinctoidea Steinmann in Steinmann and Döderlein, 1890 is an important representative of the Holcodiscidae from a stratigraphic point of view. In areas where the zonal index Acanthodiscus radiatus (Bruguière, 1789) does not occur, as in Butkov Quarry, the first representatives of Spitidiscus indicate the base of the Hauterivian. The genus Plesiospitidiscus Breistroffer, 1947 was long regarded as a member of the Superfamily Desmoceratoidea Zittel, 1895. This superfamily was based on its type species, Eodesmoceras celestini (Pictet and Campiche, 1860), which is not Valanginian in age, as now clearly proven. As a consequence, this superfamily is considered invalid. Vermeulen and Lahondère (2011) proposed an alternative by selecting a suitable initial genus, namely Plesiospitidiscus, for the Family Barremitidae, Superfamily Barremitoidea Breskovski, 1977 ( nom. transl. Vermeulen and Lahondère, 2011).

Heavy Metal Content in the Plants (Pleurozium schreberi and Picea abies) of Environmentally Important Protected Areas of the Tatra National Park (the Central Western Carpathians, Poland)

This work concerns the content of selected heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn), and determines the effect of absolute altitude on the content of metals in the plants of the Tatra National Park (TNP). The metals were determined in two species of plants, i.e., in the moss (Pleurozium schreberi (Willd.) Mitten) and in the Norway spruce (Picea abies (L.) H. Karst). Plant samples were collected in two test areas every 100 m of the altitude of the area, starting from 1000 m above sea level in the Lake Morskie Oko test area and from 1100 m above sea level in the Kasprowy Wierch test area, and ending at 1400 m above sea level for Lake Morskie Oko, and 1750 m above sea level (the moss) and 1550 m above sea level (the spruce) for Kasprowy Wierch. The two test areas are different from each other in terms of natural and physico-geographical conditions (geological structure, landform, climatic conditions). The conducted research showed that both plant species accumulated greater amounts of heavy metals in the Lake Morskie Oko test area than in the Kasprowy Wierch test area. The moss accumulated higher values of metals compared to the spruce. In both the moss and the spruce, the highest values, exceeding the natural content, were found for Cr, Pb, Cd, and Ni. For these metals, natural values were significantly exceeded: 20 times for Cr; 10 times for Pb; 4 times for Cd; and 3 times for Ni. For both examined areas, an increase in the quantity of accumulated metals in plants was also observed with the increase in altitude. The work focuses on the spreading around of heavy metals and their deposition on plants in protected high mountain (alpine) areas, in connection with altitude. Based on the obtained research results, Spearman’s and Kendall’s rank correlations were performed, and showed statistically significant relationships between the values for the content of metals and altitude. There are no heavy metal emission sources in the study area, so it is assumed that the metal content in the plants of the TNP is affected by long-range emissions.

Quaternary faulting in the Western Carpathians: Insights into paleoseismology from cave deformations and damaged speleothems (Demänová Cave System, Low Tatra Mts)

Multiphase cave conduit offset and related speleothem damage in the Demänová Cave System (DCS; the Low Tatra Mts, Central Western Carpathians) were dated with U-series methods, revealing five events: (1) 570 (442)–417 ka, (2) 306–291 ka, (3) 184–130 ka, (4) ~19 ka, and (5) 2.56–2.3 ka. To decipher the cause of the damage, we combined geochronological data with structural, geomorphological, and seismological research. Gravity sliding as a probable source of damage is unlikely since the Demänová Valley has deepened only to a small extent for the past 550 ka and the steep fissure guiding the studied parts of the DCS extends below the recent valley. However, coseismic block sliding cannot be unambiguously excluded, as Newmark displacement analysis revealed that any >M7 earthquake in the 25 km range could have produced a 10-cm pseudostatic displacement. The studied offsets were accompanied by shaking, as inferred from fallen stalagmites and stalactites; hence, distant earthquakes are plausible damage sources. We applied ground-motion models and compared them with seismicity and scant prehistoric and historical data to identify and quantify the probable seismic source, which is most likely the Sub-Tatric Fault located 17.5 km from the cave. As inferred from the applied ground-motion models, a > M7 event on the Sub-Tatric Fault would generate a PGA >4 m/s2 in the cave despite the attenuation, which is above the threshold horizontal ground acceleration forcing the majority of speleothems to break.Although the mechanism that leads to cave passage offsets remains unclear we consider them as an off-fault damage caused by secondary faulting related to postseismic surface vertical movements, or less likely but not out of the realm of possibility distributed rupturing.

Early and Middle Jurassic tectonically controlled deposition in the High-Tatric succession (Tatricum), Tatra Mountains, southern Poland: a review

The High-Tatric succession of the Tatra Mountains represents the Tatricum domain of the Central Western Carpathians, which in the Jurassic was located on the southern margin of the incipient and expanding Vahic Ocean – a branch of Western Tethys. This paper describes the various depositional consequences of extensional tectonic activity as it impacted on sedimentation in the High-Tatric succession of the Tatra Mountains during the Early and Middle Jurassic. Evidence of such impacts on depositional style and facies development are present within the Dudziniec, Smolegowa and Krupianka formations, in all the High-Tatric tectonic units. These impacts also include erosional surfaces and sedimentary gaps separating particular formations, commonly associated with minor angular unconformities. The Lower Jurassic, pre-Bajocian, Dudziniec Formation of the Kominy Tylkowe (autochthonous) Unit is developed in mixed carbonate-clastic facies. The occurrence and proportion of sand-dominated and carbonate-dominated facies, as well as their thickness differences, were controlled by syndepositional tilt-block tectonics, taking place both in depositional and in neighbouring source areas. The Smolegowa and Krupianka formations (Bajocian–Bathonian) occur in all High-Tatric tectonic units, but in the Czerwone Wierchy and Giewont units they are represented mainly by laterally discontinuous bodies of crinoidal limestone of very limited thickness. The preservation of these deposits only in some areas, as well as their thickness reductions, are effects of differentiated subsidence and uplift of isolated blocks taking place in an extensional regime. Moreover, the Krupianka Formation abounds in condensed facies with ferruginous crusts and stromatolites – a feature characteristic of rapidly drowning ocean margins. Deposits of the Dudziniec, Smolegowa and Krupianka formations are also preserved as infills of extensive systems of neptunian dykes penetrating mainly the Triassic substrate, which is yet another classic symptom of synsedimentary extension. The dominant influence of tectonics on sedimentary development ceased with the onset of deposition of the Raptawicka Turnia Formation in the Callovian.

Tracing proto-Rheic - Qaidam Ocean vestiges into the Western Tatra Mountains and implications for the Palaeozoic palaeogeography of Central Europe

Zircon petrochronology from amphibolites and retrogressed eclogites from the basement of the Western Tatra Mountains (Central Western Carpathians) reveals a complex rock evolution. An island-arc related basaltic amphibolite from Žiarska Valley shows three distinct zircon forming events: igneous zircon growth at ca. 498 Ma (Middle/Late Cambrian) and two phases of amphibolite-facies metamorphism at ca. 470 Ma (Early Ordovician) and at ca. 344 Ma (Early Carboniferous). A retrogressed eclogite from Baranèc Mountain records two zircon forming events: metamorphic zircon growth under eclogite-facies conditions at ca. 367 Ma (Late Devonian) and amphibolite-facies metamorphism at ca. 349 Ma (Early Carboniferous). These data contribute towards understanding and correlating major tectonothermal events that shaped the eastern margin of Gondwana in the Early Palaeozoic and its subsequent Variscan evolution. The metabasites record vestiges of two completely independent oceanic domains preserved within the Central Western Carpathians: (1) An Ediacaran to Cambrian oceanic arc related to the proto-Rheic - Qaidam oceans and metamorphosed to amphibolite-facies in the Early Ordovician subduction of the proto-Rheic - Qaidam arc during the Cenerian orogeny (ca. 470 Ma) and (2) Late Devonian oceanic crust related to a back-arc basin (Pernek-type), formed by the opening of the Paleotethys and metamorphosed to eclogite-facies during Devonian subduction (ca. 367 Ma). The common Variscan and later evolution of these oceanic remnants commenced with amphibolite-facies metamorphic overprinting in the Early Carboniferous (amphibolite: ca. 344 Ma; retrogressed eclogite: ca. 349 Ma) related to an Early Variscan consolidation and the formation of Pangea. None of the investigated rocks of the Central Western Carpathians show any evidence of being chronologically or palaeogeographically related to the Rheic Ocean, therefore any prolongation of the Rheic suture from the Sudetes into the Alpine-Carpathian realm is highly problematic. Instead, the Southern and Central Alpine Cenerian orogeny can be traced into the Central Western Carpathians.

Tescheniceras gen. nov. (Ammonoidea) and the definition of the Valanginian/Hauterivian boundary in Butkov Quarry (Central Western Carpathians, Slovakia)

Jurassic and Lower Cretaceous successions of the Manín Unit of the Central Western Carpathians are exposed in Butkov Quarry in the Middle Váh Region, Slovakia. A significant part of the macrofauna belonging to neocomitid ammonites, formerly classified under the genus Teschenites Thieuloy, 1971, occurs in deposits spanning the Valanginian/Hauterivian boundary. The original definition of Teschenites was accompanied by uncertainties in the taxonomic and stratigraphic position of its original type species, i.e., Hoplites neocomiensiformis Uhlig, 1902. The present contribution focuses on and provides a possible taxonomic solution by establishing the new genus Tescheniceras. In Butkov Quarry, the new genus includes five species. Tescheniceras flucticulum (Thieuloy, 1977), the type species, is the most abundant. Tescheniceras callidiscum (Thieuloy, 1971), the subzonal species for the uppermost Valanginian (Thieuloy 1971b), occurs only sporadically. Because Acanthodiscus radiatus (Bruguiére, 1789), the index species for the basal Hauterivian (radiatus Zone) in the international ammonite zonation, does not occur in the locality, the basal Hauterivian is indicated by the first appearance of the genus Spitidiscus Kilian, 1910.

New paleomagnetic constraints for the large-scale displacement of the Hronic nappe system of the Central Western Carpathians

The thin-skinned Hronic nappe system represents the structurally highest tectonic unit in the Late Cretaceous thrust-stack of the Central Western Carpathians. It mostly comprises a Permian volcano-sedimentary sequence and Triassic carbonate sediments which crop out in different parts of the Central Western Carpathians. We carried out a systematic paleomagnetic study on 24 Permian and 20 Triassic localities geographically distributed over 300 km in W-E direction. Several samples from each locality were drilled and oriented in-situ and specimens cut from them subjected to standard paleomagnetic and magnetic mineralogy experiments. The results were evaluated using principal component analysis, statistical evaluation of the characteristic remanences, and applying inclination-only and tilt tests. We documented the pre-tilting age of remanences for the majority of both the Permian and Triassic age groups. However, the latter was interpreted as remagnetized during the Cretaceous Normal Super-Chron in the course of nappe stacking between 90−80 Ma. The Permian group is exhibiting about 70°, the Triassic about 34° clockwise vertical axis rotations with respect to the present north. There is no indication in our data set for oroclinal bending of the Hronic Unit. We interpret the difference in clockwise rotations (about 36°) between Permian and 90−80 Ma as a clockwise block rotation taking place during major extensional and/or compressive events between stable Europe and Africa. Taking into consideration the well-documented counterclockwise rotation observed for the overstep sequences in the Central Western Carpathians and in the Pieniny Klippen Belt, the remagnetization of the Triassic sediments was closely followed by about 94° clockwise rotation. Research in progress will serve to decide if this large clockwise rotation involved the whole Central Carpathian nappe stack or part of this was due to the thin-skinned nappe emplacement of the Hronic Unit.

Assessing anoxia, recovery and carbonate production setback in a hemipelagic Tethyan basin during the Toarcian Oceanic Anoxic Event (Western Carpathians)

Abstract The chemostratigraphic record of the Toarcian Oceanic Anoxic Event (T-OAE) is generally well documented in epicontinental basins; however, the duration of anoxia and recovery remains poorly constrained in the Tethys Ocean owing to limited stratigraphic resolution of oceanic sections with hiatuses. In this paper, we describe a relatively continuous hemipelagic record in the Central Western Carpathians of Slovakia (Skladana Skala section), which contains the Pliensbachian/Toarcian boundary, the T-OAE, and the subsequent recovery phase. In our section, the Pliensbachian Spinatum Zone is represented by a ~ 7 m thick alternation of spotted, spiculitic marly limestones and limestones of the Allgau Formation that contain moderately diverse trace fossils including abundant Zoophycos, Lamellaeichnus and Teichichnus. In the uppermost part of the Spinatum Zone, a ~ 0.8‰ decline in δ13Ccarb values marks the carbon isotope excursion (CIE) at the Pliensbachian/Toarcian boundary. This isotope anomaly is overlain by a ~ 3 m-thick interval of spotted marly limestones and marls, which contains a positive CIE that represents the base of the T-OAE. The T-OAE interval comprises a 60 cm-thick pyritic black shale interval that lacks bioturbation and shows a negative CIE (δ13Corg values drop by 4–5‰), coincident with an increase in TOC values (from 0.3% to 2–3%), and a drop in CaCO3 values (from 50 to 80% to 3–7%). The black shale is overlain by ~8 m thick marls with rare intercalations of marly limestones, which show ammonites of the Exaratum Subzone in the lowermost part (~1 m) succeeded by Serpentinum Zone beds. This unit exhibits a second positive CIE (δ13Corg increases by 2.5‰ and δ13Ccarb increases by 1.5‰), significantly more negative δ18O values relative to the pre-T-OAE interval, and a low diversity of trace fossils dominated by Chondrites and extremely thin Zoophycos. Sponge spicules re-appear in the uppermost 6.5 m-thick interval of the section formed by the alternation of spotted marls and limestones, with ammonites of the Falciferum Subzone in the lower part and of the Bifrons Zone in the uppermost parts; however, diversity of trace fossils remains low. Based on these findings, we argue that the 60 cm-thick pyritic black shale that represents the T-OAE is a strongly condensed succession because it includes the onset of the negative CIE and the subsequent rebound, and thereby encompasses the full duration of the anoxic event. Anoxia in basins open to the oceanic Tethys thus coincided not only with reduced carbonate production but also with reduced siliciclastic supply, generating very thin black shale deposits. In contrast to current-swept swells where black shales associated with hardgrounds are thin or missing owing to winnowing, carbonate starvation was induced by a calcification crisis coincident with the T-OAE and siliciclastic starvation was probably induced by rapid sea-level rise. Although bottom waters were not anoxic in the aftermath of T-OAE, bioturbation remained restricted during the Falciferum Subzone in basinal settings, indicating that environmental stress induced by limited ventilation and/or high bottom-water temperatures were persistent. The reduced diversity of trace fossils and the re-appearance of sponge spicules close to the lower/middle Toarcian boundary indicate that the ecological recovery in basins open to the oceanic Tethys was delayed, a pattern similar to the epicontinental seas that experienced anoxia.

Early Cretaceous ammonites of the superfamily Bochianitoidea from the Butkov Quarry (Central Western Carpathians, Slovakia)

The paper deals with the description of three heteromorphic ammonites of the superfamily Bochianitoidea that occur in the lower part of the Lower Cretaceous exposed in the Butkov Quarry. In addition to the one-shaft genus Bochianites, two species of the genus Euptychoceras occur in the quarry. Euptychoceras represents three-shaft ammonites with the so-called ptychoceratoid shells. Besides the genus Euptychoceras with a trifid lobe A, a stratigraphically younger group of similar ptychoceratoids co-occur, however, with a rather different suture line. Together with the description of ammonites, the taxonomy of bochianitids, which has been multiply redone and reinterpreted since its "classical" presentation in Wright et al. (1996), is discussed in detail.

Last scene in the large scale rotations of the Western Carpathians as reflected in paleomagnetic constraints

This paper provides an overview of the paleomagnetic results which constrain the post-Paleogene tectonic development of the Western Carpathians. A group of these results are relevant to the last stage of the Tertiary folding and thrusting of the Silesian, Dukla and Magura nappes of the Outer Western Carpathian and were obtained from Paleogene-Lower Miocene flysch sediments. Both the pre- and post-folding remanences indicate about 50° CCW vertical axis rotation with respect to the present orientation. This is about a 60° rotation relative to stable Europe. It follows that the general orientation of the Silesian and more internal nappes were NW-SE, at least until the mid-Miocene. The CCW vertical axis rotation was co-ordinated with that of the Central Carpathian Paleogene Basin. The termination of the rotation can be estimated from the paleomagnetic data available from the Pieniny andesites which intruded the Pieniny Klippen Belt and the southern part of the Magura Nappe as well as from those obtained for the Neogene intramontane basins which opened up in the Outer and in the Central Western Carpathians. The paleomagnetic vectors for the andesites form two groups. The first group suggests about 45° CCW rotation relative to north, while the second shows no rotation. At the present stage of our knowledge it seems likely that some of the andesite bodies were intruded around 18 Ma, which is the oldest isotope age for the intrusions of the Wżar Mts, while some other bodies could have been emplaced after the rotation, around 11 Ma, which is the youngest isotope age for the Brijarka quarry. Vertical axis CCW rotation was also observed on sediments older than 11.6 Ma in the Orava-Nowy Targ Intramontane Basin which saddles the Magura Nappe and the Central Carpathian Paleogene Basin. However, this rotation was related to fault zone activity and was not attributed to the general rotation of the Outer Western Carpathian nappe system. Paleomagnetic results from the Nowy Sącz Intramontane Basin, which opened over the Magura Nappe, and those for the Central Western Carpathian Turiec Intramontane Basin do not indicate vertical axis rotation. In the first case, the loosely controlled age limit of the termination of the rotation is around 12 Ma. Well constrained results from the second basin imply that the rotation was definitely over by 8 Ma. Based on the above observations, and aware of the problem of often loose age control on the formation and deformation of the deposits of the intramontane basins, it is tentatively concluded that the large scale CCW rotation of the Central Western Carpathians, together with the Magura, Dukla and Silesian nappes, must have started after 18 Ma and terminated around 11 Ma.

Provenance of Albian to Cenomanian exotics-bearing turbidites in the Western Carpathians: a heavy mineral analysis

Throughout the Cretaceous, Tethyan oceanic branches gradually closed, and various ophiolites became obducted and eroded. Their remnants, however, provide an abundance of exotic clasts of unknown origin. Sandstone samples from the oldest, Albian exotics-bearing strata of the Pieniny Klippen Belt and Central Western Carpathians were analysed for heavy minerals. These samples were dominated by a high content of chrome-spinels, zircon, tourmaline, apatite and rutile. Titanite, kyanite, monazite, epidote, sillimanite and staurolite were much less abundant. Garnet was generally also rare; however, it was locally common, as were blue amphiboles, pyroxenes and kyanite. The spinels found in the samples were predominantly derived from harzburgites (supra-subduction peridotites and volcanic rocks). The blue amphiboles represented glaucophanes to ferroglaucophanes, and were derived from HP/LT metabasites. Pyroxenes (enstatite, less commonly augite and diopside) most likely came from coeval volcanics. Most of the tourmalines were derived from metasedimentary rocks and locally from granitoids. Furthermore, some have a complex zonation with two phases of tourmaline, or tourmaline intergrown with quartz. These were likely derived from ophiolitic sources. The results from our analysis indicate a dominance of ophiolites and older sediments with local input of continental crust metamorphic rocks. A resulting palaeogeographic reconstruction involves secondary doubling of the Neotethys suture zone and its lateral shift north of the Central Western Carpathians, which formed a common source for exotics in the Pieniny Klippen Belt and the Central Western Carpathians.