The deposit Gemerská Poloma is located in the Gemeric Superunit of the Western Carpathians and it is currently mined for talc. Talc formed by metasomatic replacement of magnesite, together with ...dolomite, quartz, pyrite, and accessory minerals. Leachates of dolomite samples in 2.5 M acetic acid yield a SmNd isochron age of 271 ± 7 Ma. This age coincides with the previously published ages of the underlying, evolved granitic rocks (from 265 ± 17 to 257 ± 5 Ma, U–Th–Pb on monazite) and the UPb age of uraninite (264 ± 1 Ma) interpreted to form from fluids expelled during granite crystallization. The relationship of metasomatism and the granites is further supported by: (i) increased Li and F concentrations in the leachates from dolomite (when compared to the primary magnesite); (ii) increased total REE concentrations in dolomite (compared to magnesite) and even presence of individual REE minerals (bastnäsite) in the ore body, (iii) chondritic Y/Ho ratios, compatible with a magmatic source; (iv) the presence of skarn bodies directly above the magnesite-talc ore deposit; and (v) previously inferred low pressure of talc metasomatism, typical for contact metamorphism in shallow crustal levels. The positive europium anomalies argue for the metasomatism by the action of high-temperature (> 250 °C) hydrothermal fluids that progressively cooled below 250 °C. Thus, the observed talc metasomatism was triggered by the intrusion of the Permian granitic rocks. The Alpine processes tectonically modified the ore body, caused recrystallization and folding of the pre-existing talc and formation of new talc, and obliterated much of the evidence of the earlier processes.
•Talc metasomatism of a magnesite body resulted from an interaction with a granite intrusion.•Sm–Nd radiometric dating on dolomite constrained the timing of talc metasomatism.•Dating of hydrothermal carbonates by the NdSm method yields geologically reasonable and precise ages.
Morphometric analysis and evaluation of 260 striped field mice (Apodemus agrarius) were carried out to identify sexual size dimorphism in pelvic bones regarding the age of individuals and the ...reproductive history of females. Pelvic size was found to differ between subadult and adult individuals of both sexes. A comparison using the Mann–Whitney U test between the right and left parts of the pelvis showed statistically non-significant differences between the pelvis dimensions. In the inter-sexual comparison of both ages (subadult, adult), statistically significant differences were found for only four traits in adults: length of the coxal bone (LP1), width of the ischiopubis (WP1), length of the obturator foramen (LSF) and width of the obturator foramen (WSF). The two indices (WSF/LSF and WP1/LP2) evaluated clearly reflected changes in the pelvic shape, which were most pronounced in adult mice. For the group of subadult males and females, the differences in measured traits and indices were not as pronounced. Several analyses, such as the Mann–Whitney U test, principal component analysis (PCA) as well as discriminant analysis (DFA), showed sex differences in pelvic morphology and shape, although the two sexes overlapped. Similarly, one-way ANCOVA showed that there was a significant difference between the sexes for the adjusted means. Analyses showed that for a given body mass, it appears that females tend to have larger pelvises. Thus, the sexual dimorphism of females was related to pelvic size and shape in A. agrarius. The breeding history showed differences in pelvic dimensions in following direction: the nulliparous < primigravid < primiparous direction.
•Regional-scale dendroecological study of primary mixed beech-fir forests.•Low-and intermediate-severity disturbances were the prevailing type of events.•Plot-level events of high and very-high ...disturbance severities were also detected.•Overall, the forest was driven by a mixed-severity disturbance regime.
Natural disturbances are key factors in the formation of forest ecosystem structure. Evaluation of the spatial and temporal extent of disturbance regimes is critical for understanding forest dynamics, forest structural heterogeneity, and biodiversity habitats. Quantifying disturbance regimes is therefore imperative for appropriate management of forests and protected areas. However, natural disturbance regimes have rarely been assessed using dendrochronological methods on a regional scale across primary mixed beech-fir forest stands - one of the dominant forest vegetation types in Europe. To study the natural disturbance regimes of beech-dominated mixed-forest stands, we established 42 permanent study plots with an area of 0.1 ha across three primary forest stands in the Western Carpathians, a region that still contains large areas of primary forest. We reconstructed each stand-level disturbance history using a tree-ring based approach. The temporal synchronicity of disturbance events was then evaluated by delineating stand-level disturbance events using a kernel density function, and through the detection of plot-level disturbances with severities greater than 10 percent. The results obtained from the chronologies showed substantial variability in time and space, especially in the mid-19th century. Low- and moderate-severity plot-level disturbance events were most common, but high- and extremely high-severity plot-level disturbance events also occurred. The observed spatial and temporal variability suggests that the beech-dominated forests were primarily driven by mixed-severity disturbance regimes, with windstorms as the main disturbance agent.
This reconstruction of the disturbance regime provided unique insight into the scale of mortality processes in these beech-dominated mixed forests. This information can help guide ecological forestry in areas where both wood production and biodiversity preservation are simultaneous goals, such as by employing more spatiotemporally-complex silvicultural systems that resemble natural disturbance patterns and facilitate heterogeneous forest structures.
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.
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•W Tatra amphibolites are remnants of the Cambrian proto-Rheic - Qaidam Ocean.•W Tatra meta-eclogites protoliths are related to the opening of the Paleotethys.•Early Ordovician Cenerian Orogeny extends into the Central Western Carpathians.
Rodingitization is the metasomatic transformation of mafic lithologies into rodingite, a Ca-rich and Si-poor rock associated with serpentinized ultramafic bodies. Serpentinization and rodingitization ...occur simultaneously but it remains challenging to obtain absolute ages on these events in order to identify the geodynamic setting of their formation. In this study, we investigate rodingites from an occurrence in the Western Carpathians with the aim to define the timing of rodingite formation during the tectono-metamorphic evolution of the Carpathian Orogen. The rodingites consist mainly of vesuvianite, diopside, garnet and chlorite. They are noticeably characterized by the presence of FeTi rich aggregates composed of ilmenite, rutile, titanite and calcite. Textural relationships and chemical compositions of the investigated FeTi minerals document their hydrothermal-metamorphic origin. These minerals are characterized by considerable rare earth element (REE) concentrations with prevailing positive Eu anomaly, which presumably derives from the plagioclase-rich protolith of the investigated rodingites. Moreover, the similarity of REE patterns between the analysed phases suggests that the REE concentrations in FeTi minerals are controlled by the immobility and availability of these elements in the system. A particular lamellae texture composed of rutile and calcite originated from titanite destabilization. The titanite destabilization was triggered by cooling, silica leaching and influx of CO2-rich fluids. In situ UPb dating of rutile, which have formed by retrograde breakdown of titanite during rodingitization, yields a crystallization age of 102.6 ± 19.9 Ma. This age is in good agreement with Cretaceous ages of the regional alpine metamorphic evolution reported in the literature and suggests that the rodingitization and serpentinization processes took place during the exhumation and cooling of the accretionary wedge resulting from the closure of the Meliata Ocean.
•Fe-Ti rich aggregates occur in rodingites from the Western Carpathians.•The aggregates consist of ilmenite, rutile, titanite and calcite.•Rutile formed by retrograde breakdown of titanite.•Crystallization age of rutile is 102.6 ± 19.9 Ma, consistent with Alpine metamorphism.•Rodingitization took place during exhumation and cooling of an accretionary wedge.
Landslides are a type of mass wasting and denote any downslope movement of soil and rock under the influence of gravity; as such they can represent a dangerous natural hazard process, especially in ...case that they affect inhabited areas or transport infrastructure. Because the occurrence of landslides is typically favoured by terrain and lithological conditions, the process is frequently concentrated in relatively small, isolated regions exhibiting suitable initial conditions of terrain instability. Extensive regional assessments of landslide activity have been used in the past to uncover common triggers and process patterns, mostly in the aftermath of large, regional disasters. By contrast, however, regional reconstructions of past landslide activity have not been realized with dendrogeomorphic techniques, and with the aim to date past landslide histories over extended time periods and with annual dating precision. This study therefore aims at disentangling landslide dynamics at the regional scale (covering ca. 600 km2) by using growth-ring records of trees that grow on active landslides. The studied area of the Hostýnsko-vsetínská hornatina Mts. (Central Europe) is well known for its high landslide activity, but has so far been lacking a detailed chronology of past events. To this end, we dated past activity on 26 landslide bodies using tree-ring series from 1322 disturbed trees to reconstruct 327 landslide reactivations during the last century.
The reconstructed landslide database allowed correlations between landslide types and their frequencies or occurrence, as well as inferences between selected morphometric parameters with landslide frequency and magnitude. We also observe periods of increased landslide activity (1940s, 1960s, 1980s, and 1990s) and events of regional importance (e.g., 1961, 1985, and 1997), as well as a significant decrease in landsliding during the last two decades.
•Regional reconstruction of landslides activity for Outer Western Carpathians•Tree-ring based analysis of 26 landslides•Chronologies of various landslide types•Comparison of activity with the morphometry of landslides
In this contribution, we propose a model of Quaternary seismicity in the Outer Western Carpathians. The model presents results of analysis of fractured clasts performed in 268 exposures of Quaternary ...fluvial gravels within the ca. 5,000 km2 large segment of the Outer Western Carpathians comprising: Outer Carpathian nappes, the innermost part of the Carpathian Foredeep, and two intramontane basins – the Orava-Nowy Targ Basin and the Nowy Sącz Basin. Moreover, to precise stratigraphic position of the host gravels we performed OSL dating in 16 exposures and 14C dating in 4 exposures. Outside the intramontane basins, seismic damage in Quaternary strata is largely focused along all major overthrusts and some of the large-scale strike-slip and normal faults, whereas, within the intramontane basins, the damage is dispersed within the whole basins. Our results show that seismic damage within Quaternary strata in the Outer Western Carpathians results both from co-seismic fault rupture and from seismic shaking. During Quaternary times, the Outer Western Carpathians have been affected by earthquakes since the Pleistocene until Present. Seismic damage in Quaternary strata results from light (Mw5-) earthquakes with the exception of hanging limbs of the normal faults bordering the Orava-Nowy Targ Intramontane Basin which have been affected also by moderate (Mw5+) earthquakes. Our model can be significant for understanding seismic hazards in low-seismicity thrust-and-fold belts. In the studied case, this is important as the densely populated intramontane basins show the largest seismic damage.
Late Ediacaran to Cambrian metagranitoids from the northern Veporic unit of the Western Carpathians show imprints of three metamorphic events, which can be assigned to the Cenerian, Variscan, and ...Alpine orogenies based on electron microprobe dating of monazite. Metamorphic monazites in the metagranitoids are mostly of the Lower to Middle Ordovician age (480–460 Ma). The Ordovician monazite formed in equilibrium with the metamorphic assemblage garnet, biotite, kyanite, ilmenite and quartz at P-T conditions of 6–7 kbar and 550–570 °C, thus providing clear evidence for Cenerian metamorphism in the Western Carpathians. Variscan metamorphism caused minor monazite growth/recrystallization at 364 ± 13 Ma and produced a new mineral assemblage garnet, kyanite, rutile and phengite at P-T conditions of 20–22 kbar and 670–690 °C. The low-grade Alpine metamorphism is recorded by monazite of Cretaceous age (96 ± 23 Ma), but only in orthogneiss of extremely low-Ca composition.
The Veporic metagranitoids show incomplete transformation from magmatic stage, still preserving remnants of plagioclase, K-feldspar and high-Ti biotite. This indicates that the metagranitoids remained relatively dry and failed to complete metamorphic reactions due to kinetic factors at fluid-deficient conditions. Nevertheless, the metagranitoids likely underwent significant geochemical changes during their metamorphic evolution including a severe loss of CaO and Na2O.
•First recognition of Ordovician metamorphism as the result of Cenerian orogeny in the Western Carpathians•Ordovician, Carboniferous and Cretaceous orogenic events revealed by monazite dating, mineral assemblages, P-T conditions•Polymetamorphosed metagranites with preserved magmatic and multiple metamorphic stages due to fluid-deficient conditions
