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Wyświetlanie 1-5 z 5
Tytuł:
The Wenlock-Ludlow carbon isotope trend in the Vidukle core, Lithuania, and its relations with oceanic events
Autorzy:
Martma, T.
Brazauskas, A.
Kaljo, D.
Kaminskas, D.
Musteikis, P.
Powiązania:
https://bibliotekanauki.pl/articles/2058950.pdf
Data publikacji:
2005
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Lithuania
Silurian
carbon isotopes
oceanic events
sedimentary facies
Opis:
A Wenlock to Ludlow terrigenous-carbonate succession in the Vidukle core in Central Lithuania represents a deep shelf environment with a general upwards-shallowing trend, interrupted by brief deepening episodes. The carbon isotope trend, based on 115 whole-rock analyses, shows three main excursions: (1) a major excursion (δ13 C values reach 3.2‰) in the lower Wenlock, (2) low shifts (1.3‰ and 1.6‰) at two levels in the upper most Wenlock Siesartis Formation corresponding to the Monograptus ludensis Biozone, (3) the most prominent excursion (δ13 C values reach 8.2‰) occurs in the upper Ludlow Mituva Fm. The upper Ludlow excursion is dated by the last occurrences of Polygnathoides siluricus below the main shift and the appearance of Ozarkodina wimani and O. crispa above the excursion. The excursion stratigraphically coincides with the Lau oceanic Event and is correlated with the mid-Ludfordian Neocucullograptus kozlowskii-Bohemograptus bohemicus tenuis Biozone. Changes in the carbon isotope trend are in general harmony with some aspects of the rock (CaO, terrigenous component) and fossil content of the section. The data presented are consistent with an arid climate model for the Ludfordian isotope event.
Źródło:
Geological Quarterly; 2005, 49, 2; 223--234
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Foraminiferal and calcareous nannoplankton bioevents and changes at the Late Cretaceous : earliest Paleogene transition in the northern margin of Tethys (Hyżne section, Polish Carpathians)
Autorzy:
Machaniec, Elżbieta Katarzyna
Kowalczewska, Oliwia
Jugowiec, Małgorzata
Gasiński, M. Adam
Uchman, Alfred
Powiązania:
https://bibliotekanauki.pl/articles/2060246.pdf
Data publikacji:
2020
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
foraminifera
nannoplankton
bio-events
K-Pg boundary
Skole Nappe
Outer Carpathians
Opis:
Foraminifera and calcareous nannoplankton from the Cretaceous-Paleogene (K-Pg) transition in the Hyżne section (Outer Carpathians, south-eastern Poland) show a relatively complete biostratigraphic record. Despite the absence of the Pα Zone in turbiditic deposits of the Polish Carpathians, the planktonic foraminiferal zones of the Late Cretaceous-Early Paleogene interval are well defined, including (1) the late Maastrichtian Abathomphalus mayaroensis Zone and its equivalents, (2) the earliest Danian Guembelitria cretacea second bloom Zone (P0 Zone), and (3) the top of the early Danian Parasubbotina cf. pseudobulloides (P1a) Zone. The foraminiferal events recorded in the studied section at the K-Pg transition are stratigraphically important. They include: (1) the interval with A. mayaroensis occurrence, (2) the interval with gradual disappearance of planktonic foraminifera from the most complex K-strategy forms, through the less specialized species to the large Heterohelicidae turnovers, and (3) the G. cretacea first and second blooms. Furthermore, the bloom of the opportunistic, benthic Bolivinita sp., the size reduction event, and the dissolution of the tests of the planktonic foraminifera are recorded. The K-Pg interval bioevents can be useful for better stratigraphic resolution of the flysch deposits of the Outer Carpathians. The nannoplankton event is represented by the appearance of Cruciplacolithus primus, which marks the onset of the return to more stable environmental conditions after the perturbations at the K-Pg boundary. The K-Pg boundary occurs within dark grey marly mudstones, above the upper boundary of the G. cretacea first bloom, and above the highest occurrence of the agglutinated foraminifera Goesella rugosa, at the top of the nannofossil CC 26 Zone, and below the deep-water agglutinated foraminifera (DWAF) dominance. The foraminiferal assemblages derive from different bathymetric zones corresponding to (1) the upper bathyal zone in the late Campanian (nannoplankton CC 22 Zone) and early late Maastrichtian (A. mayaroensis Zone), (2) the shelf margin in the latest late Maastrichtian (CC 26 nannoplankton Zone, G. cretacea first bloom), (3) the shelf margin in the earliest Danian (G. cretacea second bloom, Np1/2 Zone), and (4) the middle-lower bathyal depth, below a local foraminiferal lysocline and above CCD, in the latest early Danian (P. pseudobulloides Zone). As the foraminifera could have been redeposited by turbiditic currents, they do not necessarily show real bathymetric changes in the area of deposition. Such changes have not been observed in sedimentary features of the studied deposits. Foraminiferal and nannoplankton assemblages are typical of the “transitional zone” between the Tethyan and Boreal domains.
Źródło:
Geological Quarterly; 2020, 64, 3; 567--588
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cretaceous and Eocene tectono-thermal events determined in the Inner Western Carpathians orogenic front Infratatricum
Autorzy:
Putiš, Marián
Danišík, Martin
Siman, Pawol
Nemec, Ondrej
Tomek, Čestmír
Ružička, Peter
Powiązania:
https://bibliotekanauki.pl/articles/2058652.pdf
Data publikacji:
2019
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Inner Western Carpathians
Infratatricum
orogenic wedge
tectono-thermal events
zircon fission track
Opis:
This paper re-assesses the tectono-thermal evolution of the frontal Infratatricum part of the Inner Western Carpathians orogen based on new geological-petrological and zircon fission track (ZFT) data and published 40Ar-39Ar and K-Ar data. The study area is in the Považský Inovec Mts. in Western Slovakia, where the Infratatric Inovec Nappe comprises a micaschist-gneiss basement and Upper Carboniferous-Lower Cretaceous cover with the Jurassic-Lower Cretaceous Humienec Succession; this latter is reconstructed from olistoliths in the Horné Belice Succession Upper Cretaceous flysch. The Infratatric Inovec Nappe posterior part is thrust over its frontal Humienec tectonic Slice with infolded Upper Cretaceous sediments. This nappe exhibits very low-temperature tectono-thermal overprinting, and this is documented by electron probe microanalysis of metamorphic phases and P-T estimates. The late Early Cretaceous age of this D1 stage event at approximately 115-95 Ma is recorded by 114 ±2 and 106 ±4 Ma phengitic white mica 40Ar-39Ar ages from a Lower Cretaceous cherty slate, and by 101 ±3 Ma 40Ar-39Ar age and 102 ±4 Ma ZFT age from Permian meta-sandstone. The Inovec Nappe was thus derived from an Albian-Early Cenomanian accretionary wedge. The hemipelagic Upper Turonian to Lower Santonian red marls and upward syn-orogenic Upper Santonian to Maastrichtian flysch were deposited on the frontal attenuated part of the Inovec Nappe-type basement in the inferred Pieninic-Váhic (~South-Penninic) zone. This flysch contains olistolithic to clastogeneous metamorphosed material, including the Lower Cretaceous slates, supplied from the posterior part of the Inovec Nappe. The 40Ar-39Ar age of 86 ±2 Ma from this nappes' Permian meta-sandstone is consistent with D2 thrusting at approximately 95-85 Ma and Horné Belice foreland flysch basin supply in the D3 stage at ~85-65 Ma. The Inovec Nappe frontal Humienec tectonic Slice with infolded Upper Cretaceous sediments suggests formation of a Paleocene-Eocene accretionary wedge at approximately 65-40 Ma in the D4 stage. This event is constrained by 40Ar-39Ar age of 48 ±2 Ma from the Tatricum hanging wall blastomylonites and whole-rock K-Ar age of 46 ±3 Ma from a Permian basalt olistolith in the footwall Infratatricum Horné Belice flysch. The Infratatricum finally became part of an Eocene accretionary wedge north of the Hrádok-Zlatníky thrust-fault, and reheating and exhumation cooling is documented by 57-37 Ma ZFT ages. Although the Infratatricum exhibits Late Cretaceous and Eocene tectono-thermal imprints, it is a remnant of the Early Cretaceous structure at the Inner Western Carpathian front. This imposes the Infratatricum as a distal continental margin of the Penninicum.
Źródło:
Geological Quarterly; 2019, 63, 2; 248--274
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Organic carbon accumulation events in the mid-Cretaceous rocks of the Pieniny Klippen Belt (Polish Carpathians) : a petrological and geochemical approach
Autorzy:
Wójcik-Tabol, P.
Powiązania:
https://bibliotekanauki.pl/articles/2059136.pdf
Data publikacji:
2006
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Pieniny Klippen Belt
mid-Cretaceous
oceanic anoxic events
black shales
geochemical indicators
Opis:
New petrological and geochemical data lead to a consistent depositional model of the Corg.-rich sedimentation within the Pieniny Basin during themid-Cretaceous. Considerable terrestrial runoff into the Pieniny Basin occurred during the late Albian. Detritalmacerals accumulated under aerobic conditions on the shelf and continental slope. Fertilization of surface water induced primary productivity; aerobic degradation of organic matter led to the development of an oxygen-minimumzone within mid-water. The oxygen-minimumzone spread over almost all of the Pieniny Basin (Albian/Cenomanian). At the same time, a stagnant pool developed in the Grajcarek Basin. During the mid-Cenomanian the O2 minimum zone retracted and covered only the shelf and upper/middle slope. Stagnant pools might have formed in the depressions. Turbidity currents flowed down the slope and deposited calciturbiditic sequences with organic detritus in the Branisko and Pieniny basins. At the end of the Cenomanian, isolated anoxic or even H2S-bearing basins existed on the shelf. The slope was still occupied by the oxygen-minimum zone. In the deepest part of the sea-floor a stagnant basin formed.
Źródło:
Geological Quarterly; 2006, 50, 4; 419-436
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fossils from the Silesian-Subsilesian series of the Polish Western Carpathians : the implications for changes in sea-level and the marine environment during the Albian-Turonian
Autorzy:
Szydło, A.
Jugowiec-Nazarkiewicz, M.
Olszewska, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059811.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
fossils
calcareous nannoplankton
environments
sea-level
anoxic and biotic events
Albian-Turonian
Subsilesian-Silesian zone
Western Outer Carpathians
Polska
Opis:
Fossils and exotics from the Albian-Cenomanian deposits of the Western Polish Carpathians are discussed in relation with changes in depositional environments. Environmental conditions were controlled by geotectonic activity, sea-level changes and also anoxic and biotic events. During the Albian-the Early Cenomanian, and in the Turonian the fall in sea level led to increased supply of coarse-grained material rich in siliceous and sometimes calcareous bioclasts and exotics. This cyclic process has contributed to changes in the marine biota. In the Albian monogenic foraminiferal assemblages with the surficial epifauna corresponding to the organic influx and oxygen deficiency (OAE 1b) were evolved into more variable associations including deep infauna, which indicated more aerobic conditions. Under these conditions also preserved planktonic and calcareous benthic fossils, which indicated the supply of terrigenous material from shallow-water environments and land. During the Albian-Turonian transition intensive subsidence and volcanic activity associated with eustatic sea-level rise led to intensive production of phytoplankton. The sea-surface productivity and enhanced upwelling resulted in expanded short-term oxygen minima at the end of the Albian (OAE 1d) and the Cenomanian (OAE 2). In the latter interval benthic forms almost extinct while siliceous and calcareous plankton survived. In the Turonian changes in sea-level and sedimentary regime led to recolonization of the basin bottom.
Źródło:
Geological Quarterly; 2015, 59, 1; 215--228
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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