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Wyszukujesz frazę "Tatra Mountains" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Microstructures of shear zones from selected domains of the Western Tatra Mountains
Autorzy:
Kania, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059986.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
structures
kinematics
shear zones
Western Tatra Mountains
Opis:
The paper is focused on the meso- and microstructural characteristics of selected shearing zones in the Western Tatra Mts. The domains of crystalline rocks studied (Długi Upłaz Ridge, Rakoń Mt., Zabraty Ridge and Zabrať Pass, Wołowiec Mt., Trzydniowiański Mt., Czubik Mt. and Jarząbczy Mt.) show evidences of heterogeneous shearing with development of shear zones. Four types of shear zones were distinguished: (1) ductile shear zones in gneisses, (2) brittle-ductile complex shear zones, (3) gneisses with clear later brittle deformation; (4) leucogranites, produced by anatexis with later brittle deformation. The development of these shear zones is characterised by occurrences of various types of fault rocks: cataclasites, S-C cataclasites and mylonites. The different shearing-related rocks and structures are interpreted as an effect of protolith diversity and strain partitioning. Shape-preferred orientation is an important structural feature of all the shearing-related rocks. Kinematic analyses revealed generally a southward sense of shearing documented by structures related to brittle conditions and northwards sense of shearing recognised in ductily sheared crystalline rocks. The time relationships between different shear zone types are discussed, leading to the conclusions that the 1st type of shear zone is pure Variscan, the 2nd type is Variscan with Alpine brittle deformation, and the 3rd and 4th types are mainly Alpine brittle deformations of Variscan syntectonic anatectic leucogranites.
Źródło:
Geological Quarterly; 2015, 59, 4; 679--699
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Upper Jurassic bacteria from the Raptawicka Turnia Limestone Formation in the Mały Giewont area (Western Tatra Mountains, Poland)
Autorzy:
Pszczółkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2060080.pdf
Data publikacji:
2018
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
fossil bacteria
micro-oncoids
Kimmeridgian-Tithonian
Tatra Mountains
Opis:
Fossil filamentous and non-filamentous bacteria are reported from the Upper Jurassic limestones of the Raptawicka Turnia Limestone Formation in the Mały Giewont sections of the Western Tatra Mountains (Poland). The filamentous bacteria are subdivided into five groups: thin uniseriate, large multi-cell, large spiral, tapering and branched forms. The thin uniseriate filaments are the main microbial component of the peloids and micro-oncoids from the studied formation, mainly in the Upper Kimmeridgian-Tithonian limestones. The presence of the heterocyte-like terminal cells suggests their interpretation as cyanobacteria similar to the modern order Nostocales and perhaps to the family Nostocaceae. The large multi-cell and tapering filaments are uncommon in the studied limestones. The branched filaments found in the Tithonian limestones, although thinner, probably also may be compared with some modern representatives of the order Nostocales. Non-filamentous fossil bacteria found in the studied limestones consist of rod-shaped bacilli, monotrichous bacilli and spirilla; they belong mainly to the phylum Proteobacteria. Some microborings observed in the microfossils occurring in the micro-oncoids remind the ichnotaxon Scolecia filosa Radtke known to be of wide palaeobathymetric range. The thinnest microborings resemble another group of ichnofossils named “Pygmy form”, probably also of bacterial origin. The Upper Kimmeridgian-Tithonian micro-oncoids were formed mainly by filamentous bacteria (Cyanobacteria) that overgrew successively their nuclei with a few to several laminae. Frequent occurrence of pelagic microfossils as nuclei of micro-oncoids does not match a transport of these coated grains from much shallower sedimentary environments. The fossil filamentous bacteria filling up the peloids and micro-oncoids could be adapted to conditions that existed in the sublittoral zone below the wave base.
Źródło:
Geological Quarterly; 2018, 62, 4; 840--857
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microfabric diversity and grain shape analysis of fault rocks from the selected areas of the Western Tatra Mountains
Autorzy:
Kania, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059963.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
microfabrics
grain shape analysis
fault rocks
shear zones
Western Carpathians
Western Tatra Mountains
Opis:
Fault rocks in brittle and brittle-ductile shear zones played a key role in the evolution of the Western Tatra Mountains crystal- line rocks (Poland-Slovakia). Microfabrics of these rocks, including grain shape analyses, were investigated in the six areas of the Western Tatra Mountains. Based on studies of thin sections, 14 types of fault rock microfabric are distinguished, ac- cording to the following criteria: (a) the presence and abundance levels of a cataclastic matrix and (b) the presence and form of a preferred orientation features. General tendencies observed in these areas indicate southwards increasing non-coaxial deformation as well as the domination of ultracataclasites or ultramylonites to phyllonites in areas with negative relief (e.g., sedlo Zabrat’ Pass, Dziurawa Przełęcz Pass). A model of shear zone evo l u tion embracl ng foll owl ng three stages is pro- posed: (1) deformation partitioning and block-controlled cataclastic flow, (2) matrix-controlled cataclastic flow, (3) selective leaching and deposition of silica, leading to the formation of softened and hardened deformation domains respectively. These microstructural observations were supported by statistical analyses of the grain shape indicators (compactness, isometry, ellipticity, solidity, convexity). Two trends of relationships between compactness and convexity were noted: the first, horizontal on the correlation diagrams, was interpreted as an effect of rapid cataclasis and then sericitization, the sec- ond, with a strongly negative correlation coefficient, was considered as an effect of long-term cataclastic flow. The different microfabric data and microstructural interpretations described in this paper are consistent with a new model of the tectonic history of the Western Tatra Mountains evolution, with an important role for a non-coaxial deformation during Alpine orogeny in brittle and brittle-ductile conditions.
Źródło:
Geological Quarterly; 2014, 58, 1; 3--18
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stratigraphic position of alkaline volcanic rocks in the autochthonous cover of the High-Tatric Unit (Western Tatra Mts., Central Western Carpathians, Slovakia)
Autorzy:
Madzin, J.
Sýkora, M.
Soták, J.
Powiązania:
https://bibliotekanauki.pl/articles/2059966.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Central Western Carpathians
Western Tatra Mountains
autochthonous cover of the High-Tatric Unit
alkaline volcanism
biostratigraphy
Opis:
Biostratigraphic investigations of carbonate strata that sandwich volcanic rocks and studies of the volcanic rocks were made along five composite lithological sections across the Upper Jurassic-Lower Cretaceous carbonate rocks of autochthonous cover of the High-Tatric Unit in the Osobitá peak area of the Western Tatra Mts. A carbonate microbreccia that consists almost exclusively of limestone clasts containing calpionellids occurs immediately below the volcanics. The youngest identified microfossil Calpionella elliptica Cadisch in the individual limestone clasts showed the age of breccia formation to be younger than late Early-early Middle Berriasian. The volcanic rocks are overlain by the Osobitá Limestone Formation, which in the lowermost horizons consists of a few metres thick crinoidal limestone containing the foraminifers Meandrospira favrei (Charollais, Brönnimann & Zaninetti), Sabaudia minuta Hofker and Montsalevia salevensis (Charollais, Brönnimann & Zaninetti) indicating a Late Valanginian-Early Hauterivian age. The biostratigraphical and sedimentological data obtained show that volcanism took place in several phases. Less intense phases of volcanism are recorded as thin tuffitic laminae within the upper parts of the Tithonian-early Mid Berriasian Sobótka Limestone Member and as fragments of volcanic rock in the carbonate breccia. The main phase(s) of volcanism took place during the Late Berriasian-?Early Valanginian.
Źródło:
Geological Quarterly; 2014, 58, 1; 163--180
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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