Not every large glacial episode lowers valley bottoms: inisghts from the cave systems of the Tatra Mts (the Western Carpathians)

<p>The Tatra mountains, the northernmost portion of the Central Western Carpathians, host a stunning alpine landscape despite an average elevation that rises 1.4 km above the surrounding lowlands. Regional geomorphology studies on both sides of the range correlate various landforms interpreted to be glacial in origin with all each of the eight major Alpine glacial  events based largely landscape position, and in some cases geochronologic constraints. This regional relative chronology assumes that wet-based mountain glaciers are efficient agents of erosion and each successive glaciation lowered the valleys within the Tatra. While the tendency of subsequent glaciations to obscure evidence of previous events makes it difficult to study the work done by past glacial episodes, the cave networks on the northern side of the Tatra offer a way to evaluate the amount and timing of valley lowering with U-series dating of speleothems. Epiphreatic and paleophreatic caves that developed near the water table and dried out as valley deepening occurred can serve as excellent recorders of the valley incision history.</p><p>Speleothems were collected from a number of cave levels present throughout the northern Tatra, of which only a subset were suitable for U-series geochronology. The oldest speleothems collected in active epiphreatic passages on the valley bottom level from each valley are consistently between 284-325 ka (MIS 8-9). This shows that the modern karst drainage system of the Tatra was established prior to the late Middle Pleistocene, and the cave conduits changed to epiphreatic or vadose conditions between 280 and 330 ka. Since the lowest cave level is at or below the modern valley floor, we can conclude that no valley incision occurred after ~330 ka, which includes both the penultimate and last glaciations periods. Clearly, the regional glacial chronologies in the Tatra must be reassessed. The implications of our findings demonstrate that the assumption of successive valley lowering should not be assumed and that even the extensive MIS2 glaciation did not result in valley lowering despite its size.</p>

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.

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.

Minerály skupiny columbitu a mikrolitu v granitovom pegmatite pri Liešťanoch: prvý výskyt vzácnoprvkovej Nb-Ta mineralizácie v Strážovských vrchoch (Slovenská republika)

Accessory minerals of columbite and microlite groups were identified in granitic pegmatite dike intruded into parental Carboniferous (~350 Ma) leucogranites of the crystalline basement of the Tatric Unit, Central Western Carpathians. The pegmatite is situated on E slope of Bystrý Hill near Liešťany village, the Strážovské vrchy Mts., Slovakia. Primary columbite-(Fe) forms euhedral crystal (~3 mm across) with diffuse internal zoning reflecting a relatively small compositional variations: Mn/(Mn + Fe) = 0.40 - 0.45 and Ta/(Ta + Nb) = 0.21 - 0.24. Secondary anhedral domains of Ta-rich columbite-(Fe) to tantalite-(Fe) (≤200 μm) with Mn/(Mn + Fe) = 0.45 - 0.47 and Ta/(Ta + Nb) = 0.45 - 0.62 partly replace primary columbite-(Fe) along crystal rims. Moreover, secondary subhedral crystals of microlite-group minerals (≤25 μm) form fracture fillings in columbite-(Fe). The microlites show uniform high Ta/(Ta + Nb) ratio (0.77 - 0.80) and U content (7.7 - 10.2 wt.% UO2; 0.18 - 0.21 U apfu) but different contents of F, Ca, Na and Pb: central parts locally show fluorcalciomicrolite composition (~2 wt.% F, ~9.5 wt.% CaO, 2.2 - 2.7 wt.% Na2O), whereas main microlite mass forms zero-valent-dominant microlite with inclusions (≤8 μm) of Pb-rich zero-valent-dominant microlite (16.8 - 19.7 wt.% PbO; 0.46 - 0.56 Pb apfu). Textural relationships and chemical compositions of Nb-Ta minerals indicate primary magmatic origin of columbite-(Fe) and post-magmatic (early subsolidus to late hydrothermal) formation of secondary Ta-rich columbite-(Fe) to tantalite-(Fe) and microlite-group minerals.

Recycling of Paleoproterozoic and Neoproterozoic crust recorded in Lower Paleozoic metasandstones of the Northern Gemericum (Western Carpathians, Slovakia): Evidence from detrital zircons

U–Pb (SHRIMP) detrital zircon ages from the Early Paleozoic meta-sedimentary rocks of the Northern Gemericum Unit (the Smrečinka Formation) were used to characterize their provenance. The aim was to compare and reconcile new analyses with previously published data. The detrital zircon age spectrum demonstrates two prominent populations, the first, Late Neoproterozoic (545–640 Ma) and the second, Paleoproterozoic (1.8–2.1 Ga), with a minor Archean population (2.5–3.4 Ga). The documented zircon ages reflect derivation of the studied metasedimentary rocks from the Cadomian arc, which was located along the West African Craton. The acquired data supports close relations of the Northern Gemericum basement with the Armorican terranes during Neoproterozoic and Ordovician times and also a close palinspastic relation with the other crystalline basements of the Central Western Carpathians. In comparison, the detrital zircons from the Southern Gemericum basement and its Permian envelope indicate derivation from the Pan-African Belt–Saharan Metacraton provenance.

Turbidite sedimentology, biostratigraphy and paleoecology: A case study from the Oligocene Zuberec Fm. (Liptov Basin, Central Western Carpathians)

Outcrops of a thick turbiditic succession are exposed on the northern bank of the Liptovská Mara reservoir near Liptovská Ondrašová and Ráztoky. The section consists of rhythmic, predominantly thin- to medium-bedded turbidites of the Rupelian age. Their biostratigraphy is based on the calcareous nannofossils. Facies associations of these deposits represent different components of depositional lobe deposits in the turbidity fan system, including mainly the lobe fringe and lobe distal fringe/inter-lobe facies associations and locally the medium bedded deposits of the lobe off-axis facies association. This interpretation is supported by statistical analysis. The deep-sea turbiditic deposits contain trace fossil associations, which include deep-tier fodinichnia and domichnia up to shallow-tier graphoglyptids. Paleocurrent measurements indicate that the majority of sedimentary material was transported from SW and W.