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Wyszukujesz frazę "Peri-Tethys" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
Triassic micro-charcoal as a promising puzzle piece in palaeoclimate reconstruction: An example from the Germanic Basin
Autorzy:
Götz, Anette E.
Uhl, Dieter
Tematy:
wildfire
palaeoclimate
Triassic
Peri-Tethys
Germany
Pokaż więcej
Wydawca:
Polskie Towarzystwo Geologiczne
Powiązania:
https://bibliotekanauki.pl/articles/2171822.pdf  Link otwiera się w nowym oknie
Opis:
Fossil charcoal is the primary source of evidence for palaeo-wildfires and has gained increasing interest as a proxy in the reconstruction of past climates and environments. Today, increasing temperatures and decreasing precipitation/humidity appear to correlate with increases in the frequency and intensity of wildfires in many regions worldwide. Apart from appropriate climatic conditions, sufficient atmospheric oxygen (>15%) is a necessary precondition to sustain combustion in wildfires. The Triassic has long been regarded as a period without evidence of wildfires; however, recent studies on macro-charcoal have provided data indicating their occurrence throughout almost the entire Triassic. Still, the macro-palaeobotanical record is scarce and the study of micro-charcoal from palynological residue is seen as very promising to fill the gap in our current knowledge on Triassic wildfires. Here, the authors present the first, verified records of micro-charcoal from the Triassic of the Germanic Basin, complementing the scarce macro-charcoal evidence of wildfires during Buntsandstein, Muschelkalk and Keuper (Anisian-Rhaetian). The particles analysed by means of scanning electron microscopy (SEM) show anatomical features typical of gymnosperms, a major element of the early Mesozoic vegetation following the initial recovery phase after the PT-boundary event. From the continuously increasing dataset of Triassic charcoal, it becomes apparent that the identification of wildfires has a huge potential to play a crucial role in future studies, deciphering Triassic climate dynamics. The first SEM study of micro-charcoal from palynological residue spanning the entire Triassic period, presented here, is a key technique to further unravel the charcoal record as a puzzle piece in palaeoclimate reconstruction.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Platy corals from the Middle Triassic of Upper Silesia, Poland : implications for photosymbiosis in the first scleractinians
Autorzy:
Kołodziej, Bogusław
Łabaj, Marcelina A.
Szulc, Joachim
Morycowa, Elżbieta
Salamon, Klaudiusz
Opis:
Coral patch reefs from Middle Triassic (upper Pelsonian-lower Illyrian) strata in the Upper Silesia region of southern Poland (Germanic domain of the Peri-Tethys) are rare examples of the first scleractinian buildups. The shallowing-upward succession in the Tarnów Opolski quarry records a transition from sponge to coral patch reefs interbedded with bioclastic limestones. Coral pillarstones built by thin, branching Volzeia szulci are succeeded by platy Pamiroseris silesiaca constructing two platestone layers, each up to 50 cm thick. Serial sections through platestones revealed flat to undulose growth form of P. silesiaca. The maximum observable dimension of the coral plates is 24 cm wide (typically up to 12 cm), while thickness of most plates is 1-1.5 cm. Coral plates are interlayered with crinoidal wacke- to packstone and microbialites, which are locally important component of the platestone. Platy corals grew in a shallow, turbid-water environment with changing, but dominantly moderate hydrodynamics. Net sedimentation was low, as indicated by the epibionts encrusted to the undersides of the coral plates, and locally common microbial fabrics. Growth-interruptions of P. silesiaca record events of storm-induced sediment input and resuspension of carbonate mud. Based on the euphotic floor model, the flattened morphology of P. silesiaca is interpreted as an optimal growth form in a turbid, low-light environment. Platy scleractinian assemblages from Silesia are the oldest occurrences of this ecological coral group (mostly representing deeper, mesophotic habitats) and support the hypothesis that some of the earliest scleractinians had photosymbionts like modern zooxanthellae.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Lithostratigraphy and micropalaeontological characteristic of Lower Cretaceous strata in central part of the Carpathian Foreland
Litostratygrafia i charakterystyka mikropaleontologiczna utworów kredy dolnej w środkowej części przedgórza Karpat
Autorzy:
Bobrek, Lucyna
Urbaniec, Andrzej
Świetlik, Barbara
Opis:
During the Early Cretaceous a central part of the Carpathian Foreland was situated in the Peri-Tethys area. That zone was located on the SW margin of the East European Craton and it was adjacent to the Tethys basins in the south. Impact of those both zoogeographic provinces (the Boreal Sea and the Tethys Ocean) is easily noticeable in assemblages of microfauna. Character of sedimentation in the Early Cretaceous basin of the Carpathian Foreland is connected mainly with changes of the sea-level as well as tectonic activity of this region. The stratigraphy and facies data are based on near two hundreds wells profiles. Detailed sedimentological profiles and photographic documentation of the Upper Jurassic and the Lower Cretaceous deposits from about 50 boreholes were done as well as micropalaeontological and microfacial studies of core samples. The presented work is an attempt of unification and formalization of lithostratigraphic units' nomenclature.Two boreholes: Zagorzyce-7 and Wiewiórka-4 were suggested as stratotype sections of distinguished formations. Jurassic-Cretaceous boundary is probably situated within limits of Ropczyce formation in this area. Three formations have been distinguished in the profile of Lower Cretaceous above Ropczyce formation: Zagorzyce limestone-marl formation (Berriasian age), Dębica marl and organo-detritic limestone formation (Valanginian) and Wiewiórka limestone formation (Late Valanginian-Hauterivian). The most marked erosion surface is recorded between Zagorzyce and Dębica formations. We suppose that hiatus including a large part of Lower Valanginian profile is connected with that erosion surface. It could be refered to a rapid fall of the sea-level in the Tethys Ocean, noticed inter alia in the Western Carpathians and the Northern Calcareous Alps. The known existing thickness of the Lower Cretaceous sediments in the middle part of Carpathian Foreland (total of three formations: Zagorzyce fm.,Dębica fm. and Wiewiórka fm.) rises to 188 m in Zagorzyce-1 well.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Middle Triassic evolution of the northern Peri-Tethys area as influenced by early opening of the Tethys Ocean
Ewolucja środkowotriasowa północnej Paratetydy i jej związki z rozwojem Oceanu Tetydy
Autorzy:
Szulc, J.
Tematy:
late Scythian-Carnian
Tethys
Peri-Tethys
basin analysis
sequence stratigraphy
paleogeography
paleoenvironments
Pokaż więcej
Wydawca:
Polskie Towarzystwo Geologiczne
Powiązania:
https://bibliotekanauki.pl/articles/191262.pdf  Link otwiera się w nowym oknie
Opis:
During Middle Triassic times, the Germanic or northern Peri-Tethys Basin pertained to the western Tethys Ocean. The basin was closed from the north and open toward the Tethys by tectonically controlled depressions (gates). The gates were opened in different times. The marine incursions broke first (as early as in late Scythian time) through the eastern gates and from the Polish Basin advanced gradually to the west. Semiclosed disposition of the basin resulted in its distinctive environmental diversification. Open marine environments developed along the southeastern margins which should be regarded as an integrate part of the Tethys Ocean rather than the epicontinental sea. Northward and westward from the Silesian and Carpathian domains the environments became more restricted. This resulted in significant facies diachronity between the western and eastern parts of the basin. As indicated by the faunal diversity, facies variability and geochemical properties of the sediments, during almost entire Anisian time the open marine sedimentation dominated in the eastern part while the western part displayed restricted circulation, typical for the semi-closed, evaporitic basin. The circulation reversed in Ladinian time when the westward shift of the tethyan spreading center gave rise to opening of the western gate. Meanwhile, the eastern and northern parts of the basin were uplifted and underwent emersion by the end of the Ladinian. Evolution of the southern parts of the Germanic Basin (Silesia, Holy Cross Mts., SW Germany) has been directly influenced by the Tethys rifts. The crustal motion was transmitted from the Tethys rift onto its northern periphery by reactivated Hercynian master faults. The Northern Germany and the North Sea basins were controlled by the North Atlantic-Arctic rift system. The central part of the basin was dominated by thermal subsidence. Despite of the intense synsedimentary tectonism affecting the basin, the distinguished 3rd order depositional sequences resulted from eustatic controls. The concordance between the tethyan and peritethyan sequence stratigraphy argues for the overregional, eustatic nature of the sequences. Faunal migration from the Tethys into its northern periphery followed generally the rift-controlled opening of the seaways within the Tethys. The first tethyan faunas which appeared in the south-eastern part of the Polish Basin as early as in Induan time came from the eastern branch of the Tethys Ocean (Paleo-Tethys). The next migration waves proceeded by western branches of the spreading ocean (Neo-Tethys) and entered the Germanic Basin through the Silesian-Moravian Gate (in Anisian time) and through the Western Gate from Ladinian time onward.
W czasie środkowego triasu basen germański należał do północnego obrzeżenia Oceanu Tetydy nazywanego północną Perytetydą. Taka pozycja paleogeograficzna wskazuje że basen germański należy traktować raczej jako integralną część zachodniej Tetydy niż jako typowy basen epikontynentalny. Bezpośrednie połączenie między obszarem germańskim a Tetydą utrzymywane było przez system tektonicznie generowanych obniżeń (bram) rozwiniętych w obrębie speneplenizowanego lądu windelicko-bohemskiego stanowiącego strukturalną barierę między otwartym oceanem i jego strefą peryferyjną. Przez większą część środkowego triasu basen germański wykazywał cechy basenu półzamkniętego o ograniczonej i jednokierunkowej cyrkulacji. Taki układ hydrologiczny powodował ewaporacyjny wzrost zasolenia wód basenu w miarę oddalania się od strefy dopływu wód oceanicznych. Znajduje to potwierdzenie w wyraźnym ubożeniu zespołów fauny zasiedlającej zbiornik jak i w zapisie izotopów stabilnych węgla i tlenu. Otwieranie bram miało charakter diachroniczny i postępowało ze wschodu na zachód. Najwcześniej, bo już w środkowej części wczesnego triasu otwarta była tzw. Brama Wschodniokarpacka. W anizyku głównym połączeniem była Brama Morawsko-Śląska a w ladynie Brama Zachodnia. Diachronizm w otwieraniu bram był pochodną migracji głównej strefy spreadingu tetydzkiego, która przemieszczała się ze wschodu na zachód. Wyróżnione dla basenu germańskiego sekwencje depozycyjne trzeciego rzędu wykazują dobrą korelację z sekwencjami z basenów alpejskich co pozwala stwierdzić, że cykle transgresywno-regresywne w basenie germańskim kontrolowane były głównie przez wahania eustatyczne. Subtropikalna pozycja paleogeograficzna północnej Perytetydy warunkowała jej gorący i półsuchy klimat. Okresowe zwilgotnienia w późnym ladynie i w karniku były pochodną przebudowy tektonicznej i intensywnej działalności wulkanicznej w obrębie Tetydy.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Litostratygrafia i charakterystyka mikropaleontologiczna utworów kredy dolnej w środkowej części przedgórza Karpat
Lithostratigraphy and micropalaeontological characteristic of Lower Lithostratigraphy and micropalaeontological characteristic of Lower
Autorzy:
Urbaniec, A.
Bobrek, L.
Świetlik, B.
Tematy:
kreda późna
przedgórze Karpat
Perytetyda
mikroskamieniałości
formacje litostratygraficzne
Lower Cretaceous
Carpathian Foreland
Peri-Tethys
Pokaż więcej
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:
https://bibliotekanauki.pl/articles/2074749.pdf  Link otwiera się w nowym oknie
Opis:
During the Early Cretaceous a central part of the Carpathian Foreland was situated in the Peri-Tethys area. That zone was located on the SW margin of the East European Craton and it was adjacent to the Tethys basins in the south. Impact of those both zoogeographic provinces (the Boreal Sea and the Tethys Ocean) is easily noticeable in assemblages of microfauna. Character of sedimentation in the Early Cretaceous basin of the Carpathian Foreland is connected mainly with changes of the sea-level as well as tectonic activity of this region. The stratigraphy and facies data are based on near two hundreds wells profiles. Detailed sedimentological profiles and photographic documentation of the Upper Jurassic and the Lower Cretaceous deposits from about 50 boreholes were done as well as micropalaeontological and microfacial studies of core samples. The presented work is an attempt of unification and formalization of lithostratigraphic units’ nomenclature. Two boreholes: Zagorzyce-7 andWiewiórka-4 were suggested as stratotype sections of distinguished formations. Jurassic–Cretaceous boundary is probably situated within limits of Ropczyce formation in this area. Three formations have been distinguished in the profile of Lower Cretaceous above Ropczyce formation: Zagorzyce limestone-marl formation (Berriasian age), Dębica marl and organodetritic limestone formation (Valanginian) andWiewiórka limestone formation (Late Valanginian-Hauterivian). The most marked erosion surface is recorded between Zagorzyce and Dębica formations. We suppose that hiatus including a large part of Lower Valanginian profile is connected with that erosion surface. It could be refered to a rapid fall of the sea-level in the Tethys Ocean, noticed inter alia in theWestern Carpathians and the Northern Calcareous Alps. The known existing thickness of the Lower Cretaceous sediments in the middle part of Carpathian Foreland (total of three formations: Zagorzyce fm., Dębica fm. andWiewiórka fm.) rises to 188 m in Zagorzyce-1 well.
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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