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    Wyświetlanie 1-6 z 6
    Tytuł:
    Barnasiówka Radiolarian Shale Formation - a new lithostratigraphic unit in the Upper Cenomanian-lowermost Turonian of the Polish Outer Carpathians (Silesian Series)
    Formacja Łupków Radiolariowych z Barnasiówki - nowa jednostka litostratygraficzna w górnym cenomanie i najniższym turonie w Polskich Karpatach Zewnętrznych (Seria Śląska)
    Autorzy:
    Bąk, K.
    Bąk, M.
    Paul, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/191433.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    lithostratigraphy
    biostratigraphy
    Cenomanian
    Turonian
    Silesian Nappe
    Outer Carpathians
    Opis:
    A new lithostratigraphic unit - the Barnasiówka Radiolarian Shale Formation - is herein defined. It belongs to the Silesian Series of the Outer Carpathians. The formation consists of biosiliceous deposits rich in organic matter, laid down around the Cenomanian-Turonian boundary. The formation includes, from bottom to top: (1) a series of green to black, calcareous and siliceous shales, alternating with layers of chert, siliceous siltstone and sandstone (up to 10 m thick); (2) a series of green to black, argillaceous to siliceous shales, intercalated with tuffites, bentonites, and a ferromanganese layer (up to 9 cm thick) in its middle part (up to 3.2 m thick); (3) a series of green and red, siliceous siltstones and cherts with intercalations of non-calcareous green shales and benthonites (up to 2 m thick). The total thickness of the formation ranges from 0.5 m in the eastern part (reduced tectonically?) up to about 14-15 m in the middle and the western parts of the Silesian Nappe, due to the increase in the number and thickness of turbidite intercalations. The formation represents the Holocryptocanium barbui - Holocryptocanium tuberculatum through the Alie-vium superbum radiolarian zones and the Uvigerinammina praejankoi-Uvigerinammina jankoi foraminiferal zones, which correspond to the Upper Cenomanian through the lowermost Turonian. Microfacies and geochemical characteristics of the distinguished lithological types are presented in this paper, based on recent studies and published data. The described formation has been compared and correlated with deposits of similar age from other tectonic- facies units of the Outer Carpathians in Poland and Ukraine.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2001, 71, No 2; 75-103
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    First Upper Cretaceous dinosaur track assemblage from Jordan (Middle East) : preliminary results
    Autorzy:
    Klein, Hendrik
    Gierliński, Gerard
    Lallensack, Jerns N.
    Abu Hamad, Abdalla
    Al-Mashakbeh, Habes
    Alhejoj, Ikhlas
    Konopka, Marcin
    Błoński, Marcin
    Powiązania:
    https://bibliotekanauki.pl/articles/1836264.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    Ajlun Group
    Na’ur Formation
    Cenomanian
    footprints
    theropod
    sauropod
    ornithopod
    Opis:
    Dinosaur tracks from Jordan (Middle East) have only been briefly reported in geological overview papers and books. We present here the first description and documentation of Jordanian dinosaur tracks based on a new tracksite from the south-central part of the country. The track-bearing strata belong to marginal marine (tidal flat) deposits of the Na’ur Formation (Upper Cretaceous, Cenomanian). This unit largely consists of well-bedded limestones, dolomites and marls that contain abundant marine invertebrate fossils such as bivalves, ammonites and foraminifers. The dinosaur ichnofauna occurs on four different levels and comprises abundant theropod tracks and trackways as well as isolated sauropod and ornithopod tracks. Theropod trackways consist of two different morphotypes. Morphotype 1 is tridactyl (26 cm pes length) and with a broad, but short metatarsal area and resembles the ichnogenus Picunichnus from the Lower Cretaceous (Albian) of Argentina. Morphotype 2 (36 cm pes length) has extensive and narrow metatarsal impressions continuously occurring along regularly-spaced trackways. This suggests either a plantigrade movement of the trackmaker or reflects preservational factors. By their over-all-shape with thin digits, Morphotype 2 resembles described penetrative tracks suggesting a strong influence of the substrate. Sauropod tracks are relatively small (40 cm pes length) and show low heteropody with a kid-ney-shaped manus imprint, pointing to a Sauropodichnus-like form. The single ornithopod pes track (18 cm in length) is similar to material described as Ornithopodichnus from the Lower Cretaceous of Korea. Due to the incomplete material of sauropod and ornithopod prints, no concrete assignment is given to this material and further study is needed. The presence of dinosaur tracks proves a temporary subaerial exposure of the surface whereas the main part of the Na’ur Formation is dominated by subaqueous activity of marine faunas.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2020, 90, 3; 331-342
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Successive stages of calcitization and silicification of Cenomanian spicule-bearing turbidites based on microfacies analysis, Polish Outer Carpathians
    Autorzy:
    Bąk, B.
    Górny, Z.
    Bąk, K.
    Wolska, A.
    Stożek, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/191355.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    calcitization
    silicification
    sponge spicules
    spicule-bearing turbidites
    cherts
    Cenomanian
    Outer Carpathians
    Opis:
    Mid-Cretaceous turbidites with large proportions of sponge spicules are widely distributed in the Silesian Nappe of the Outer Carpathians, giving rise to diversified types of sediments, from spiculites to spicule-bearing siliciclastics and calcarenites. Part of this succession, Middle–Late Cenomanian in age, was transformed into cherts. A microfacies study showed that these turbidite sediments underwent several stages of calcitization and silicification, which took place during Mid-Cretaceous times in different sedimentary environments, i.e., on a northern shelf bordering the Silesian Basin and on a deep sea floor. The first diagenetic changes were related to changes to the biotic components of the turbidite layers, dominated by siliceous sponge spicules. This process, which took place in the spiculitic carbonate mud on the shelves, was related to the calcitization of sponge spicules. Calcareous clasts and calcified skeletal elements also were corroded by bacteria. After transportation down the slope, the biogenic and siliciclastic particles were deposited below the carbonate compensation depth. Taphonomic processes on the basin floor and alternating phases of carbonate and silica cementations, recrystallization and dissolution occurred in these sediments and were related to the diversification in composition of successive turbidite layers. Silicification was related to the formation of quartz precipitates as fibrous chalcedony or microcrystalline quartz, which were derived from the earlier dissolution of amorphous silica, originating mostly from siliceous sponge spicules and radiolarian skeletons. However, a source of silica from hydrothermal vents was also possible. The initial silica precipitation could have taken place in a slightly acidic environment, where calcite was simultaneously dissolved. A number of silicification stages, visible as different forms of silica precipitate inside moulds after bioclasts, occur in the particular turbidite layers. They were related to changes in various elements of the pore-water profile after descending turbidity-current flows. A very low sedimentation rate during the Middle–Late Cenomanian in the Silesian Basin may have favoured the sequence of initial calcitization and silicification stages of the turbidite sediments.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2015, 85, 1; 187-203
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Environmental changes during the Cenomanian-Turonian Boundary Event in the Outer Carpathian basins: a synthesis of data from various tectonic-facies units
    Zmiany w środowisku basenów Karpat zewnętrznych w czasie globalnego zdarzenia oceanicznego na granicy cenomanu i turonu; synteza wyników badań z różnych jednostek tektoniczno-facjalnych
    Autorzy:
    Bąk, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/191660.pdf
    Data publikacji:
    2007
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    Cenomanian-Turonian boundary event
    stratigraphy
    palaeoenvironment
    Late Cretaceous
    Outer Carpathians
    Polska
    Opis:
    The paper summarizes the results of author’s studies on the environmental changes around the Cenomanian-Turonian Boundary Event (CTBE) in the Outer Carpathian basins located close to the northern margin of the Western Tethys, whose sea floor was situated below the calcite compensation depth. The sedimen- tary, biotic and chemical records allowed to recognize the successions related to the oceanic anoxic event (OAE-2) and trace changes around this event sediments within the frame of the stable carbon isotope excursion and biostratigraphic datum events. The changes so traced included changes in: type of deep-water sedimentation, accumulation rate, productivity, oxygenation of bottom water and benthic foraminiferal assemblages. Correlation of the palaeoenvironmental changes with the carbon isotope curve and biostratigraphic datum events allowed the comparisons between the various sedimentary areas in the Outer Carpathians, and with other areas of the Western Tethys. Most of the interpreted events around the CTBE were synchronous in the northern branch of the Western Tethys that extended to the Umbria-Marche and Sicily carbonate platforms. These events included: (1) an increase in productivity before the interval with the highest shift in d13C values, (2) the main interval of organic-rich sedimentation (Bonarelli level), (3) a rapid change to oxygenated sediments near the Cenomanian-Turonian (C-T) boundary and continued during the Early Turonian, (4) fluctuations in oxygen content in bottom waters with short intervals of anoxia during the earliest Turonian, (5) deposition of a thick bentonite layer, near the start of the d13C excursion, roughly synchronous with the phase of a positive shift in Pb isotopic compositions in the silicate sediment fraction in one of the Umbria-Marche sections, (6) an interval of extremely low hemipelagic sedimentation with hiatuses near the base of the C-T boundary and during the earliest Turonian, correlated with the maximum rise of the sea level. The presented data from the Outer Carpathians suggest that the OAE-2 could be triggered by enhanced productivity; however, subaerial volcanic eruptions, accompanied by hydrothermal activity and formation of large igneous provinces could also be a factor which enriched the ocean-atmosphere system in CO2. Sluggish deep- water circulation, probably deteriorating through the Late Cenomanian, favoured preservation of organic matter during the latest Cenomanian. The mechanism of rapid oxygenation of bottom waters near the C-T boundary was related to recurrent inflows of (?)saline warm and oxygenated waters.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2007, 77, No 2; 171-191
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Environmental changes around the Cenomanian-Turonian boundary in a marginal part of the Outer Carpathian Basin expressed by microfacies, microfossils and chemical records in the Skole Nappe (Poland)
    Zmiany w głębokowodnym środowisku brzeżnej części basenu Karpat Zewnętrznych wokół granicy Cenomanu i Turonu wyrażone w zapisie mikrofacji, zespołach mikroskamieniałości i chemizmie utworów w Płaszczowinie Skolskiej
    Autorzy:
    Bąk, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/191678.pdf
    Data publikacji:
    2007
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    Cenomanian-Turonian boundary event
    microfacies
    benthic foraminifers
    bulk geochemistry
    Outer Carpathians
    Polska
    Opis:
    Lithology, microfacies, benthic foraminiferal and bulk chemical analyses of the Spława section in the Skole Nappe, Outer Carpathians (Poland) reflect environmental changes across the Cenomanian-Turonian transi- tion. Biogenic-rich-turbidite sedimentation preceded the organic-rich sedimentation in the Skole Basin, termina- ting in the latest Cenomanian in response to progressive eustatic sea-level rise and to expansion of an oxygen minimum zone. The uppermost Cenomanian black, laminated, organic-rich shale series records the oceanic anoxic event (OAE-2). The benthos-free black non-calcareous shales exhibiting positive excursions of chemical redox indexes are indicative of bottom-water anoxia, interrupted by periods of suboxic conditions with sedimentation of hemipelagic green shales with poor agglutinated foraminiferal assemblages. An extremely low sedimentation rate or even a hiatus and an increase in deep-water circulation causing basin oxygenation resulted in precipitation of a ferromanganese layers and siliceous-manganiferrous variegated shales, as documented by low values of chemical redox indices. However, the lack of benthos and bioturbation, and low values of the Ce/La ratio in the subsequent succession of variegated shales (dominated by green shales) indicate a return to stressed conditions at basin floor with sluggish bottom water circulation, which occasionally resulted in sea floor anoxia with deposition of organic-rich shales. The long-termed well-oxygenated conditions at the basin floor appeared in the Early Turo- nian, as documented by diversified benthic foraminiferal assemblages. The frequency of radiolarian-rich layers and Ba/Al and Ba/Sc ratios increase up-section, reflecting an increase in primary productivity, induced by upwelling circulation.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2007, 77, No 1; 39-67
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evidence of bacteriogenic iron and manganese oxyhydroxides in Albian-Cenomanian marine sediments of the Carpathian realm (Poland)
    Autorzy:
    Bąk, M.
    Bąk, K.
    Górny, Z.
    Stożek, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/191443.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Geologiczne
    Tematy:
    iron
    manganese
    iron-related bacteria
    Albian–Cenomanian
    Silesian Nappe
    Tatra Mts.
    Carpathians
    Opis:
    The Albian and Cenomanian marine sediments of the Silesian and Tatric basins in the Carpathian realm of the Western Tethys contain ferric and ferromanganese oxyhydroxides, visible macroscopically as brown stainings. They coat calcareous bioclasts and mineral clasts, fill pore spaces, or locally form continuous, parallel microlayers, tens of micrometers thick. Light-microscope (LM) and scanning-electron-microscope (SEM) obser- vations show that the coatings contain elongated capsules, approximately 3–5 µm across and enriched in iron and manganese, which may be remnants of the original sheaths of iron-related bacteria (IRB). Moreover, the ferric and ferromanganese staining observed under LM is similar to bacterial structures, resembling the sheaths, filaments and rods formed by present-day bacteria of the Sphaerotilus–Leptothrix group. All of the possible bacteria-like structures are well preserved owing to processes of early diagenetic cementation. If the observed structures are fossil IRB, these organisms could have played an important role in iron and manganese accumulation on the sea floor during Albian–Cenomanian time. The most plausible source of metals for bacterial concentration in the Silesian Basin might have been submarine low-temperature hydrothermal vents, as previously was hypothesized for Cenomanian–Turonian deposits on the basis of geochemical indices.
    Źródło:
    Annales Societatis Geologorum Poloniae; 2015, 85, 2; 371-385
    0208-9068
    Pojawia się w:
    Annales Societatis Geologorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-6 z 6

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