Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Variscan" wg kryterium: Temat

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-8 z 8
    Tytuł:
    Multistage structural evolution of the end-Cretaceous–Cenozoic Wleń Graben (the Sudetes, NE Bohemian Massif) : a contribution to the post-Variscan tectonic history of SW Poland
    Autorzy:
    Kowalski, Aleksander
    Powiązania:
    https://bibliotekanauki.pl/articles/1836013.pdf
    Data publikacji:
    2021
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    brittle tectonics
    tectonic trough
    post-Variscan tectonics
    post-Variscan cover
    Bohemian Massif
    Central Europe
    Opis:
    Results of a new mapping and structural field study of the Wleń Graben (North Sudetic Synclinorium, SW Poland), made up of a post-Variscan volcano-sedimentary succession, were used to set up a new model of its multiphase tectonic evolution. The Wleń Graben constitutes a narrow tectonic trough, ca. 17.5 km long and up to 3.5 km wide, superimposed on the low-grade metamorphic rocks of the Kaczawa Metamorphic Unit and bounded by steep, NW−SE-oriented, normal and reverse faults. Previously, a simple, one-stage evolution of the graben was considered, with a single Alpine age intraplate compressional event responsible for the formation of the unit. The present study shows that the Late Cretaceous (post-Santonian?) evolution of the Wleń Graben was dominated by NW−SE-oriented, normal faults during the first, extensional stage of its formation. The central and southern parts of the graben were strongly affected by NW−SE-trending reverse faults and overthrusts, which reflect the second, probably latest Cretaceous to early Palaeogene(?) compressional event of tectonic deformation. Moreover, the whole area of the graben is dissected by sinistral strike-slip faults oriented perpendicular to the graben margins, representing the third stage of deformation (late Palaeogene–Neogene). The latest stage of evolution of the Wleń Graben includes a possible Neogene to Quaternary development of normal faults, interpreted here as gravitational collapse structures related to present-day morphology, rather than tectonically induced ones.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2021, 91, 1; 37-66
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the new wildflysch-to-flysch, blueschist-rich Lower Visean succession of the Western Sudetes (SW Poland)
    Autorzy:
    Wajsprych, B.
    Achramowicz, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/973638.pdf
    Data publikacji:
    2003
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    wildflysch
    olistosthromes
    blueschists
    silicified evaporites
    Variscan orogen
    Lugo-Sudeticum
    Opis:
    Field and laboratory works realized in last years allowed us to redefine one of the lithotectonic units of the western Sudetes, till now considered to be composed of Cambrian to Lower Carboniferous, stratigraphically coherent, volcano-sedimentary succession, as the Lower Carboniferous, probably lower Visean, wildflysch-to- flysch succession. This unit forms the westernmost part of the Kaczawa Complex and is situated at the boundary zone between the Kaczawa Mts. (Polish Sudetes) and the Görlitzer Schiefergebirge (Germany) or - at a larger scale - between the Sudetes and Lugian tectonostratigraphic zones of the Variscan orogen. Petrographical studies of rocks sampled from the larger allochthonous bodies (olistolithes and slide-sheets) of the wildflysch sequence have revealed some peculiar features of the lithic composition of this succession. They consist in the presence of: (1) - unmetamorphosed and metamorphosed volcanites with a distinct HP-overprint, characteristic of supra- subduction zones, gabbro-type plutonites, and relatively numerous detrital chromite grains indicating the occur- rence of ophiolite ultramafics in the source area; and (2) - large block(s) of rock composed of quartz (almost 100% SiO 2 ), previously interpreted as Palaeozoic quartz vein, now documented by the authors to be totally silicified primary evaporites, composed of gypsum (selenite), anhydrite and salt. The last finding would be of special significance as the first strong evidence of evaporites within the Variscan orogenic complex in Europe, if further studies confirm proposed here tectonic position of the silicified evaporites. General lithic composition of the Jędrzychowice/Ludwigsdorf wildflysch detrital material is characterised by the presence of such litholog ies, as: black and gray-to-green cherts, black shale mudstones and cherts, (turbi- dite-)siliciclastics, carbonates (both bioclastic and diagenetic), basic and acid, unmetamorphosed and epi-to- HP-metamorphosed volcanites, and gabbros and ultrabasites (the latter noted only by detrital chromites). Moreover, the siliciclastic material of the olistosthrome matrix discloses the presence of acid magmatic (granites) and high-grade metamorphics of gneiss-to- mica-schist type in the source areas. Such a compositio n of detrital material clearly reflects a typical tectonic mélange as the source terrane for the wildflysch deposit. It would mean that the Jędrzychowice/Ludwigsdorf wildflysch should be considered as the next, strong and unequivocal signal of large-scale tectonic mélange stage in a tectonic/geodynamic evolution of the Central European Palaeozoic orogenic system.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2003, 73, No 2; 123-137
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Middle Devonian brachiopods from the southern Maїder (eastern Anti-Atlas, Morocco)
    Autorzy:
    Halamski, A. T.
    Baliński, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/191427.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    systematics
    Brachiopoda
    Morocco
    Devonian
    Eifelian
    Givetian
    Variscan Sea
    palaeobiogeography
    Opis:
    Sixty-two Middle Devonian brachiopod species are described on the basis of >1300 specimens from the Taboumakhlof Formation (and subordinately probably also from the top of the El Otfal Formation) at Madne el Mrakib (middle to late Eifelian or early Givetian?), Aferdou el Mrakib (late Eifelian to middle Givetian), and Guelb el Maharch (early Givetian) on the southern edge of the MaÎder Syncline (eastern Anti-Atlas, Mo- rocco). Representatives of Craniida (2 taxa), Strophomenida (5), Productida (2), Orthotetida (2), Orthida (5), Pentamerida (5), Rhynchonellida (9), Atrypida (14), Athyridida (7), Spiriferida (9), and Spiriferinida (2) are present. The fauna is dominated quantitatively by the Atrypida (24% of taxa, about the half of specimens, and the commonest species Atryparia dispersa making up about 13% of the material); the Rhynchonellida (16% of taxa, about one-sixth of specimens) are the second largest order. A new genus of the family Pugnacidae (order Rhynchonellida), Paulinaerhynchia, is proposed with the type species P. paulinae gen. et sp. nov. from Maharch; it is closest to Pugnax, from which it differs in distinct costation, lack of a dorsal septum and septalium, and rudimentary dental plates. Desquamatia (D.) deserti sp. nov., a large and finely costate representative of the genus, is described also from Maharch. Antirhynchonella and Glosshypothyridina are reported for the first time or con- firmed to be present in the Givetian. Forty (possibly up to 46) species (71 or possibly up to 82% of the taxa identified at the species level) are present also in either Eifel (Germany) or the Holy Cross Mountains (Poland). Such a high ratio of species in common attests to unconstrained faunal exchanges among benthic faunas between the northern and southern shores of the Variscan Sea during the Middle Devonian. This favours the palaeogeo- graphic hypothesis of a narrow Variscan Sea.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2013, 83, 4; 243-307
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Late Cretaceous palaeogeography of NE Bohemian Massif : diachronous sedimentary successions in the Wleń Graben and Krzeszów Brachysyncline (SW Poland)
    Autorzy:
    Kowalski, Aleksander
    Powiązania:
    https://bibliotekanauki.pl/articles/1836017.pdf
    Data publikacji:
    2021
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    Sudetic epi-Variscan cover
    shallow-marine palaeostrait
    wave-dominated sedimentation
    tidal currents
    offshore transition
    Opis:
    This paper provides a new sedimentological and palaeogeographic interpretation of the Late Cretaceous (late Cenomanian to early Coniacian) shallow-marine succession exposed in the Wleń Graben and in the Krzeszów Brachysyncline (NE Bohemian Massif, Sudetic Block). These two tectonic subunits are outliers of the North Sudetic and Intra-Sudetic synclinoriums, respectively, and contain relics of the diachronous sedimentary succession of a seaway linking the Boreal and Tethyan marine provinces during the Late Cretaceous. Results of sedimentological study and facies analysis show that the late Cenomanian sedimentation within this corridor was dominated by strong in situ reworking of the pre-Cretaceous bedrock driven by storm waves and possibly tidal currents. In the latest Cenomanian, siliciclastic sedimentation was followed by the deposition of offshore-transition to offshore muddy calcareous facies in the Krzeszów area, while the deposition of coarse-grained siliciclastic facies continued in the Wleń area. The nearshore clastic belt in the latter area changed into a wider strait dominated by offshore sedimentation in the early Turonian, whereby the interconnected Wleń and Krzeszów passages evolved into a uniform strait of fully-marine sedimentation. In the middle Turonian, the southern part of the strait became progressively filled with coarse-grained siliciclastic material supplied from the east. At the end of the late Turonian and in the early Coniacian, the strait funnelled bi-directional tidal currents along its axis. The youngest Cretaceous strata in the Wleń area comprise erosional relics of the early Coniacian shoreface to offshore-transition deposits. The younger Cretaceous deposits are unpreserved, probably eroded during the post-Santonian(?) tectonic inversion of the Wleń–Krzeszów strait. Despite the relatively small distance between the two relic parts of the strait, the shallow-marine succession reveals distinct diachroneity on a regional scale, reflecting an interplay of eustatic changes, differential tectonic subsidence and clastic sediment supply. This paper presents the first detailed sedimentological logs from the two study areas, with new findings of fossil fauna and flora, proposes a new palaeogeographic interpretation and discusses the influence and development of the source areas for the Cretaceous Sudetic Wleń–Krzeszów marine strait at the NE fringe of the Bohemian Massif.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2021, 91, 1; 1-26
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Triassic palaeogeography of NE Bohemian Massif based on sedimentological record in the Wleń Graben and the Krzeszów Brachysyncline (SW Poland)
    Autorzy:
    Kowalski, Aleksander
    Powiązania:
    https://bibliotekanauki.pl/articles/1836356.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    fluvial sedimentation
    Buntsandstein
    Polish Buntsandstein Basin
    Triassic Germanic Basin
    epi-Variscan cover
    Bohemian Massif
    Opis:
    This paper presents a new sedimentological and palaeogeographic interpretation of the Early to Middle(?) Triassic continental deposits in the Wleń Graben and the Krzeszów Brachysyncline (Sudetes, SW Poland). These two tectonic subunits, located in the peripheral segments of the North Sudetic and Intra-Sudetic synclinoriums, respectively, represent the crucial elements for deciphering the post-Variscan palaeogeographic evolution of the NE termination of the Bohemian Massif. Sedimentological studies and facies analysis show that the Early Triassic siliciclastic deposition in both areas was dominated by fluvial sedimentation of the typical Buntsandstein facies within a gently sloping alluvial plain, locally followed by ephemeral lake environments in the late Early or Middle(?) Triassic. The lithofacies and the measured palaeocurrent directions indicate that the area was drained by braided streams flowing towards the northwest and north. Individual fluvial channels had depths not exceeding 1 m and widths of up to a few metres. Overbank deposits are poorly preserved due to the lateral shifting of channels. Based on available borehole data, an analysis of isopach maps was performed for the first time in the study areas. The study areas are presently separated by crystalline units devoid of sedimentary rocks, but the analysis indicate that they might have been in constant or periodical connection during the Triassic. It is concluded that the present-day extent of Triassic deposits is a result of the primary basin configuration combined with the Middle Triassic to Late Cretaceous erosion and post-Cretaceous tectonic uplift. The paper summarizes the present state of research on the continental Triassic preserved in the terminal parts of the North Sudetic and Intra-Sudetic synclinoriums, presents the first detailed sedimentological logs, and proposes new palaeogeographic interpretation. New findings include bioturbation structures, such as plant-root traces or tunnels formed by invertebrates and possible tetrapod footprints, which shed new light on the sedimentological interpretation of the continental Mesozoic deposits in the NE part of the Bohemian Massif.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2020, 90, 2; 125-148
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal history of Lower Palaeozoic rocks from the East European Platform margin of Poland based on K-Ar age dating and illite-smectite palaeothermometry - 481 – 509
    Autorzy:
    Kowalska, Sylwia
    Wójtowicz, Artur
    Hałas, Stanisław
    Wemmer, Klaus
    Mikołajewski, Zbigniew
    Buniak, Arkadiusz
    Powiązania:
    https://bibliotekanauki.pl/articles/191840.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    shale gas
    K-Ar dating
    thermal history
    Variscan orogeny
    Palaeozoic
    East European Platform
    interlaboratory comparison
    Opis:
    Large-scale shale gas prospecting in the Polish part of the East European Platform did not discover large reserves of this resources. The article presents new research indicating that one of the reasons for the lack of shale gas relates to the thermal history of the Lower Palaeozoic rocks. Illite-smectite palaeothermometry was used to reconstruct the history of the platform and determine the maximum temperatures to which these rocks were subjected. The age of illitisation was also constrained using the K-Ar method. This method allowed precise dating of the maximum age of thermal transformations due to the deposition of numerous pyroclastic horizons (K-bentonite) throughout the entire geological profile from the Cambrian to the Silurian. Isotopic dating was made on over 53 samples of Lower Palaeozoic bentonites and low-grade metamorphic clays. These results were supplemented by analysis of the degree of thermal (smectite to illite) transformation in the profiles of 37 deep boreholes. 11 zones could be distinguished with different tectonic histories within the Polish part of the East European Platform edge. Maximum heating occurred in this region at about 320–340 Ma, corresponding to the Early Carboniferous or the turn of the Early and Late Carboniferous, phase A of the Variscan orogeny, known as the Sudetian phase. In the southern part of study area, the maximum of thermodiagenesis is slightly younger – 270–290 Ma, which responds to the Early Permian, the Asturian phase, the last phase of the Variscan orogeny. This means that the generation of hydrocarbons occurred before significant Mesozoic exhumation of the Polish part of the East European Platform, which led to the escape of a considerable amount of the gas generated. The study also presents the results of an interlaboratory comparison of illite age dating using the K-Ar and Ar-Ar methods. The comparison was conducted to find out what realistic error should be considered when interpreting geological K-Ar dating results.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2019, 89, 4; 481-509
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    How many extensional stages marked the Variscan gravitational collapse in the Bohemian Massif?
    Autorzy:
    Bárta, Ondřej
    Melichar, Rastislav
    Černý, Jan
    Powiązania:
    https://bibliotekanauki.pl/articles/1836681.pdf
    Data publikacji:
    2021
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    gravitational collapse
    anisotropy of magnetic susceptibility
    U-Pb zircon geochronology
    Variscan orogen
    Central Bohemian plutonic complex
    Opis:
    Tectonic development of the Variscan belt in Central Europe included, besides important compression, also an extensional phase related to gravitational collapse, which governed the origin of many sedimentary basins and magmatic bodies. One of these bodies is the Benešov pluton, featuring primary magmatic fabrics as well as deformational fabrics, related to subsequent extensional stages. Recognition of these fabrics and their links to other significant extension-induced structures in the Bohemicum and Moldanubicum not only sheds new light on the pluton itself but also extends a general knowledge of deformational stages, accompanying gravitational collapse of the Variscan orogen. The authors found that this pluton was strongly strained in a normal-faulting regime under brittle-ductile conditions. The age of deformation is constrained by a magmatic age of 347 ±3 Ma and by the age of Carboniferous sedimentary cover. New data indicate a three-stage extensional history during the phase of gravitational collapse: (1) Tournaisian extension (~350–345 Ma) within arc-related tonalitic intrusions; (2) late Viséan to Serpukhovian extension (~332–320 Ma), connected to the brittle-ductile unroofing and origin of a NE–SW basin system; and (3) Gzhelian to Cisuralian extension (~303–280 Ma), related to normal faulting and sedimentation in “Permo-Carboniferous” troughs, elongated NNE–SSW. Consequently, the gravitational collapse studied involved a complex succession of individual extensional stages, rather than a simple process.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2021, 91, 2; 121-136
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Age constraints on the Pre-Variscan and Variscan thermal events in the Kamieniec Ząbkowicki Metamorphic belt (the Fore-Sudetic Block, SW Poland)
    Autorzy:
    Jastrzębski, Mirosław
    Żelaźniewicz, Andrzej
    Budzyń, Bartosz
    Sláma, Jiří
    Konečny, Patrik
    Powiązania:
    https://bibliotekanauki.pl/articles/1836361.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    U-Pb geochronology
    LA-ICP-MS dating
    U-Th-total Pb geochronology
    EPMA dating
    microplates of the Bohemian Massif
    Kamieniec Ząbkowicki Metamorphic Belt
    Variscan metamorphism
    Opis:
    The Kamieniec Ząbkowicki Metamorphic Belt (KZMB) is a narrow zone of mainly mica schists, subordinate acid metavolcanics and scarce eclogites, sandwiched between Brunovistulia and the northern tip of the Teplá-Barrandia microplates. Locally occurring high-pressure relics indicate subduction of the metasedimentary succession of the KZMB, the origin and provenance of which remain unclear. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) investigations of detrital zircons show that the metapelites represent an Ediacaran-Cambrian sedimentary basin, with a maximum depositional age of 561±9 Ma. This basin was filled with detritus from a source or sources, composed of rocks containing zircons that are mainly Cryogenian-Ediacaran and Palaeoproterozoic in age. No younger component was found in the zircon population studied. The isotopic U-Pb LA-ICP-MS and chemical U-Th-total Pb electron probe microanalysis (EPMA) monazite geochronology data indicate an important regional tectono-metamorphic event at ca. 330 Ma. Though these data do not permit determination of the peak pressure from the peak temperature stages, the event was part of a complex collision of the Saxothuringian plate with Brunovistulia.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2020, 90, 1; 27-49
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-8 z 8

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies