Search Results (12)

An in situ electron microprobe study of detrital minerals yielded important insights into the diagenetic history of the Cretaceous-to-Paleogene flysch sandstones from the Chvalčov site, Rača Unit, Flysch Belt of the Outer Western Carpathians. Detrital titanite and a Fe-Ti mineral (probably ilmenite) were almost completely altered to TiO₂ minerals, which also newly crystallized in intergranular spaces of sandstone. Brookite, anatase, and, exceptionally, rutile were identified by Raman spectroscopy. Authigenic TiO₂ phases show complex composition with occasionally elevated contents of Fe, Nb, Zr, V, Sc, Cr, Al, Y, and/or P, which were likely sourced from altered neighboring heavy minerals. In addition, rare authigenic LREE- and Y-enriched apatite rims were observed on detrital apatite. The remobilization of REE, Y, and HFSE was likely mediated by acidic early diagenetic fluids enriched in fluoride and sulfate anions. The superimposed formation of calcite cement was associated with the dissolution of detrital garnet, feldspars, and quartz. The compositions of detrital apatite and garnet (Alm_60-82Prp_4-30Sps_0-24Grs_0-19) are comparable with those from adjacent parts of the Flysch Belt. Detrital rutile is enriched in Nb, V, Cr, and Zr. Our study illustrates the intensity of diagenetic alteration of detrital minerals in flysch sandstones as well as the usefulness of in-situ electron-microprobe investigations for the recognition of processes influencing heavy minerals in diagenetically altered sediments. Full article

The research area covers the border zone between the Central and Outer Carpathians. The purpose of this research was the interpretation of this zone based on a gravitational survey. This survey was integrated with the results of surface mapping, a deep seismic survey, and deep drillings. Three major tectonic units are located in this area: the Outer (Flysch) Carpathians, the Pieniny Klippen Belt (PKB), and the Central Carpathians. All three units contain a significant amount of flysch sequences. The lowering of the Bouguer anomaly value from north to south reflects the dip of the crystalline European Plate; in turn, the renewed increase in value correlates very well with the emergence of the crystalline ALCAPA Plate. The range of variability of the Bouguer anomaly value largely masks smaller anomalies in amplitude originating from smaller geological structures. Only three anomalies with significant horizontal extent and greater amplitudes are visible: two are clearly correlated with the Orava-Nowy Targ Basin and the third anomaly is likely connected with the thicker pile of the Outer Carpathian flysch. To separate the boundaries of geological or tectonic structures (lineaments), a horizontal derivative (THDR) and an analytical signal (ASA) were used. Both methods allowed us to confirm existing geological and tectonic boundaries (lineaments) and to identify new ones. Full article

The quantitative logs method is designed for objective facies analysis of thick sedimentary successions. This method enables the analysis of whole successions instead of selected intervals arbitrarily considered as representative and results in a database suitable for further analysis, e.g., statistical, quantitative stratigraphy, or facies modelling. The logging procedure involves the following steps: (i) each of the logged sedimentary features is classified according to a standard, e.g., grain-size follows the phi scale or Wentworth classes are applied for bed thickness; (ii) in the course of logging, the whole succession is subdivided into intervals, each of which is characterised by a predominant (i.e., modal) class of the considered feature; (iii) such modal class characterises a part of the section that has a specific thickness and is called a ‘modally homogeneous interval’ (MHI); and (iv) the lower and upper boundary of each MHI are defined by a change in the modal class. The thickness of all MHIs characterised by the same class interval is then added. The grand total of such component sub-totals for all class intervals of the logged feature equals the log thickness and is the basis for the calculation of frequency distribution, which characterises the succession from the viewpoint of this feature. Each bar of the resulting histogram represents the percentage of the whole section composed of the strata among which the given class occurs as the modal (i.e., predominant) feature. The method of modal quantitative logs is illustrated here with an example of statistical analysis of selected sections of the Krosno Beds (Oligocene) turbidite succession from the Western Outer Carpathians of Poland. Full article

The proper characteristics of the catchment area of dammed reservoirs is of great importance when managing their capacity in the context of enabling proper functioning, including retention of the planned amount of water and counteracting the effects of drought. Therefore, detailed analyses covered mountain reservoirs with varying degrees of capacity changes: Goczałkowice on the Vistula, Rożnów on the Dunajec and Tresna on the Soła, thanks to which reasons for the differences in these changes were determined. For this purpose, data on the volume of the suspended load was used. Diversity in its transport is mainly caused by the presence of damming structures. Correlation of morphological and hydraulic indicators was carried out, preceded by the identification and characteristics of all transverse and longitudinal structures located in catchments upstream of individual reservoirs. Analysis of the geological structure, as well as the structure of land use in the basins of the reservoirs, was also performed. The obtained results allowed for the preparation of recommendations for further work, allowing, among other things, an increase in water retention. The key factors for maintaining the capacity of retention reservoirs were defined, which may be useful in national plans or programs in the field of counteracting the effects of drought or flood protection. Full article

Based on the interpretation of 2D seismic profiles integrated with surface geological investigations, a mechanism responsible for the formation of a large scale normal fault zone has been proposed. The fault, here referred to as the Rycerka Fault, has a predominantly normal dip-slip component with the detachment surface located at the base of Carpathian units. The fault developed due to the formation of an anticlinal stack within the Dukla Unit overlain by the Magura Units. Stacking of a relatively narrow duplex led to the growth of a dome-like culmination in the lower unit, i.e., the Dukla Unit, and, as a consequence of differential uplift of the unit above and outside the duplex, the upper unit (the Magura Unit) was subjected to stretching. This process invoked normal faulting along the lateral culmination wall and was facilitated by the regional, syn-thrusting arc–parallel extension. Horizontal movement along the fault plane is a result of tear faulting accommodating a varied rate of advancement of Carpathian units. The time of the fault formation is not well constrained; however, based on superposition criterion, the syn -thrusting origin is anticipated. Full article

The present work focuses on palaeogeographic reconstruction of shallow-water carbonate deposition in the Outer Western Carpathian Tethys. Platform deposits are preserved only as a component of turbidites and olistostromes, and reconstructions of these platforms are based on clastic material redistributed into slopes and deep basins and occurring among the Outer Carpathian nappes. Similar platforms were also present on the Tethys margins. These reconstructions were performed using the global models of plate tectonics. Several ridges covered by carbonate platforms developed in that area during the latest Jurassic–Palaeogene times. Three main shallow-water facies associations—Štramberk, Urgonian, and Lithothamnion–bryozoan—could be distinguished. The Tithonian–lowermost Cretaceous Štramberk facies is related to early, synrift–postrift stage of the development of the Silesian Domain. Facies that are diversified, narrow, shallow-water platforms, rich in corals, sponges, green algae, echinoderms, foraminifera, microencrusters, and microbes are typical of this stage. The Urgonian facies developed mainly on the south margin of the Outer Carpathian basins and is characterised by organodetritic limestones built of bivalves (including rudists), larger benthic foraminifera, crinoids, echinoids, and corals. Since the Paleocene, in all the Western Outer Carpathian sedimentary areas, Lithothamnion–bryozoan facies developed and adapted to unstable conditions. Algae–bryozoan covers originating on the siliciclastic substrate are typical of these facies. This type of deposition was preserved practically until the final stage in the evolution of the Outer Carpathian basins. Full article

Hydrocarbon exploration under thrust belts is a challenging frontier globally. In this work, 1-D thermal maturity modeling of the Paleozoic–Mesozoic basement in the northern margin of the Western Outer Carpathians was carried out to better explain the thermal history of source rocks that influenced hydrocarbon generation. The combination of Variscan burial and post-Variscan heating due to elevated heat flow may have caused significant heating in the Paleozoic basement in the pre-Middle Jurassic period. However, the most likely combined effect of Permian-Triassic burial and Late Triassic–Early Jurassic increase of heat flow caused the reaching of maximum paleotemperature. The main phase of hydrocarbon generation in Paleozoic source rocks developed in pre-Middle Jurassic times. Therefore, generated hydrocarbons from Ordovician and Silurian source rocks were lost before reservoirs and traps were formed in the Late Mesozoic. The Miocene thermal overprint due to the Carpathian overthrust probably did not significantly change the thermal maturity of organic matter in the Paleozoic–Mesozoic strata. Thus, it can be concluded that petroleum accumulations in the Late Jurassic and Cenomanian reservoirs of the foreland were charged later, mainly by source rocks occurring within the thrustbelt, i.e., Oligocene Menilite Shales. Finally, this work shows that comprehensive mineralogical and geochemical studies are an indispensable prerequisite of any petroleum system modelling because their results could influence petroleum exploration of new oil and gas fields. Full article

Mountain headwater streams are still somewhat on the boundary of interest regarding possible human impact on their morphology or geomorphic processes, which may be caused by our perception of mountains as islands of relatively preserved natural conditions. This paper summarizes the past and present human pressure on the headwater streams that drain the highest mountain ranges of the Outer Western Carpathians in Czechia. Anthropogenic pressure began in this region in the 16th century during a colonization of the mountains and continued by timber harvesting, timber floating, and construction of torrent control works until present. Each of these interventions produced a morphological response of the channels in relation to altered sediment or water fluxes at the whole catchment scale or within longitudinal stream profiles. Because it is highly unlikely to reach pre-settlement conditions of the channels, the management effort should be concentrated to achieve realistic restoration targets under the present socioeconomic circumstances by taking into consideration the morphodynamical specifics of mountain headwater streams. Full article

Pre-Mesozoic exotic crystalline blocks within the Outer Carpathian flysch have potential to unravel the nature of their eroded basement source(s) and to reconstruct the Paleozoic–Precambrian history of the Protocarpathians. Strongly tectonized Campanian–Maastrichtian grey marls in the Subsilesian Nappe of the Outer Western Carpathians in Poland contain a variety of different lithology types, including granitoids and andesites. Petrological investigations coupled with zircon and apatite U-Pb dating were performed on crystalline (subvolcanic) exotic blocks from a locality in the Subsilesian Nappe. U-Pb zircon dating yields magmatic crystallization ages of c. 293 Ma for the microgranitoid and c. 310 Ma for the andesite block, with inherited zircon cores yielding Archean, Paleoproterozoic, Mesoproterozoic and Cadomian ages. Whole rock trace element and Nd isotope data imply that the melt source was composed of a significant Neoproterozoic crustal component in both the microgranite and andesite. The Late Carboniferous–Permian magmatic activity likely continues outside the Carpathian Belt and can be linked to a Late Paleozoic transtensional zone, which is a continuation of the Lubliniec–Kraków Zone that extends under the Carpathians to Moesia. This Late Paleozoic transtensional zone was probably reactivated during the Late Cretaceous under a transpressional regime within the Żegocina tectonic zone, which caused the uplift of the Subsilesian Ridge and intensive erosion. Full article

Organic-rich black shales intercalated with green radiolarian shales and bentonites, 2.2 m thick, represent an equivalent of the Bonarelli Level in the Outer Carpathian deep-water succession. Carbon stable isotope data from four sections in the Outer Carpathians show that termination of organic-rich accumulation, related to the oceanic anoxic event 2 (OAE2), occurred at the same time in this part of the Western Tethys. The excellent marker of this event is a first horizon of Fe–Mn layer (nodules), a few centimeters thick, directly covering the youngest black shale layer of the Bonarelli-equivalent Level, which is regarded as the regional chronohorizon. The youngest succession of the organic-rich shales, ca. 30 cm thick, corresponds to the latest Cenomanian interval of δ¹³C_org values displaying a negative trend, which represents a terminal part within the OAE2 carbon isotope excursion. A deep negative shift which ends this falling trend, close to the Cenomanian–Turonian boundary in δ¹³C curves from many sections around the world, is not visible in the Outer Carpathian successions. The reason for this was the long period of stratigraphic condensation, which is reflected in the ferromanganese sediments of this area. Full article

Exotic crystalline blocks within the Outer Carpathian flysch have the potential to establish the nature of their eroded basement source(s) and thus to reconstruct the paleogeography of the Outer Carpathians. Petrological investigations (including mineral analyses) coupled with zircon and apatite U-Pb dating were performed on an exotic crystalline block within Eocene siliciclastic rocks in the Rača Zone of the Magura Nappe in the Outer Western Carpathians, Poland. This exotic block is a large (c. 1 m diameter) pink porphyritic granitoid block found in the Osielczyk Stream, southeast of Osielec village in the Makowski Beskid mountains. The timing of magmatic crystallization is constrained by a U-Pb zircon age of 315.9 ± 2.6 Ma (MSWD = 0.69), while inherited zircon cores yield Archean (c. 2780 Ma), Cadomian (541.8 ± 6.7 Ma; MSWD = 0.53), Devonian (417 ± 11 Ma; MSWD = 0.57) and Early Variscan (c. 374 Ma) ages. Apatites from the same sample yield a Tera Wasserburg lower intercept U-Pb age of 311.3 ± 7.5 (MSWD = 0.87). The granitoid exhibits geochemical characteristics typical of I-type granites and εNd_{(316 Ma)} = 2.15 (with a T_DM model age of 1.18 Ga) and ⁸⁷Sr/⁸⁶Sr_{(316 Ma)} = 0.704710. These data suggest a likely source region in the Saxo-Danubian Granite Belt, which possibly formed the basement of the Fore-Magura Ridge. Full article

The anthropogenic problems in richly sculpted areas (mountain and submontane) are mainly related to agricultural activity, which shapes the quality of surface waters. This paper presents an analysis of the results of the hydrochemical tests carried out in the years 2007–2018 at check-control spots. The heavy metal pollution index (HPI < 100) indicated a low risk for aquatic organisms. The statistical calculations obtained by means of multivariate adaptive regression splines (MARS) designated that the hazard quotient (HQ) index can be combined with the electrical conductivity (EC) and total dissolved substances (TDS) parameters used in the assessment of water erosion. The HQ index showed that the concentration of individual heavy metals is lower than their value in the 0.5 percentile of the value. In subsequent studies, it should be assessed whether the size of arable land has an impact on the increased concentration of heavy metals in the surface water. We recommend small retention reservoirs as a potential management measure to improve the quality of the surface water at a regional scale. This study has great potential to mitigate the degradation processes related to the insufficient storage capacity, and to promote natural water retention. Full article