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Wyszukujesz frazę "K-Pg boundary" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
The K-Pg boundary section at Nasiłów, Poland: stratigraphic reassessment based on foraminifers, dinoflagellate cysts and palaeomagnetism
Autorzy:
Remin, Zbyszek
Cyglicki, Michał
Barski, Marcin
Dubicka, Zofia
Roszkowska-Remin, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/2060107.pdf
Data publikacji:
2021
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
K-Pg boundary
biostratigraphy
foraminifera
dinoflagellate cysts
palaeomagnetism
Nasiłów
Opis:
The Nasiłów section represents the uppermost part of the Middle Vistula River section, a classical Polish extra-Carpathian Cretaceous section, and gives access to the Cretaceous–Paleogene (K-Pg) boundary interval. Despite many papers that have been published so far, our newly collected data shed new light on the completeness of biostratigraphic and sedimentary records of the K-Pg at that site. The Nasiłów section encompasses the upper Maastrichtian regional XII and XIII foraminiferal assemblage zones and the lower Danian P0?-Pα standard planktonic foraminiferal zones. The K-Pg boundary is placed at the top of a phosphatic layer. The grey marly chalk unit, never before subjected to examination of biostratigraphically important taxa, displays blooms of guembelitrids pointing to the uppermost Maastrichtian (XIII foraminiferal assemblage Zone) as well as of planktonic and benthic foraminifers of a reduced test size. Such foraminiferal dwarfism is commonly observed near the end of the Cretaceous and interpreted as a response to the Deccan volcanism (possible 2nd phase) that caused climate changes and ocean acidification. The terminal Maastrichtian age of the marly chalk unit is additionally supported by an acme of the dinoflagellate cyst Palinodinium grallator, together with Tallasiphora pelagica and Disphaerogena carposphaeropsis. The “Greensand”, a distinct glauconite-quartz sand unit, contains exclusively terminal Maastrichtian planktonic foraminifers and dinoflagellate cyst assemblages. Individual specimens of Danian age are interpreted to be either an effect of contamination or were translocated down by burrowers into the Greensand. The lowermost portion of the Siwak (informal lithostratigraphic unit) demonstrates an early Danian age based on the co-occurrence of the common planktonic foraminifers Globoconusa daubjergensis, Guembelitria cretacea, Muricohedbergella monmouthensis, M. planispira, Planoheterohelix globulosa, Parvularuglobigerina extensa and P. alabamensis. The last occurrence of Palynodinium grallator and the first occurrences of Carptella cornuta and Senoniasphaera inornata, recorded directly above the phosphatic layer, support the same age assignment. The new palaeomagnetic data cannot prove remagnetization at the boundary interval, in contrast to previous research which gave support to a hiatus in the critical interval.
Źródło:
Geological Quarterly; 2021, 65, 3; 65: 45
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:
Dańskie amonity - obecny stan wiedzy i perspektywy badań
Danian ammonites - The present state of knowledge and perspectives for future research
Autorzy:
Machalski, M.
Jagt, J.W.M.
Heinberg, C.
Landman, N.H.
Hakansson, E.
Powiązania:
https://bibliotekanauki.pl/articles/2074714.pdf
Data publikacji:
2009
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
masa wymarła
amonity
odsłonięcia K-Pg
relikt
odrodzenie
uderzenie
anomalia irydowa
Maastricht
Dania
Holandia
New Jersey
ammonites
K-Pg boundary
mass extinctions
survival
recovery
impact
iridium anomaly
Danian
Denmark
Opis:
To date, the strongest arguments for ammonite survival into the Danian (earliest Paleogene) are based on material from the lower Danian Cerithium Limestone at Stevns Klint (Denmark), where ammonites occur above a clay layer with impact products at its base, the latter defining the Cretaceous-Paleogene (K-Pg) boundary. The best-preserved specimen is filled with Danian sediment rather than with Maastrichtian chalk, which would be expected had this been reworked material. Arguments for ammonite survival into the Danian have also been provided by specimens from the sporomorph and calcareous nannoplankton-dated lowermost Danian strata of Meerssen Member unit IVf-7, the Netherlands. Their good preservation indicates that they were not subject to any significant transport or redeposition. However, there are no unequivocal impact-related signatures in unit IVf-7, except for rare shocked quartz grains, recorded from burrows at its base. Sections in the Manasquan Basin, New Jersey, USA, provide equivocal data as far as the problem of ammonite survival into the Danian is concerned. At the top of the Tinton Formation there is a Pinna layer replete with fossils, inclusive of ammonites. Their exquisite preservation and occurrence in monospecific clusters rule out redeposition. The Pinna layer contains exclusively late Maastrichtian microfossils. However, a clear iridium anomaly has been noted at its base. Either the New Jersey ammonites survived the K-Pg event for a short time or the iridium is not in situ due to post-depositional repositioning by percolating water. Planned work is to focus on: 1) a detailed centimetre by centimetre sampling of some Cerithium Limestone basins in Denmark in search of additional ammonite material, 2) palaeontological and taphonomic analysis of ammonites and search for impact signatures in unit IVf-7 in the Netherlands, and 3) geochemical study of the iridium anomaly in New Jersey in order to determine whether its position in respect to the ammonite-bed is original or secondary.
Źródło:
Przegląd Geologiczny; 2009, 57, 6; 486-493
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
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