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Wyszukujesz frazę "fauna dynamics" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Trilobite faunal dynamics on the Devonian continental shelves of the Ardenne Massif and Boulonnais (France, Belgium)
Autorzy:
Bignon, A.
Cronier, C.
Powiązania:
https://bibliotekanauki.pl/articles/21493.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Trilobita
trilobite
fauna dynamics
fauna succession
Devonian
continental shelf
Ardenne Massif
Boulonnais region
France
Belgium
Opis:
During the Devonian the sedimentation on the continental shelves of Ardenne Massif and Boulonnais has changed from a mixed siliciclastic-carbonate ramp (Eifelian), through a carbonate barrier reef (Givetian) and then to a detritic influx with local mud-mounds (Frasnian). Here we analysed the faunistic dynamics of the trilobite associations through the changing environment. We used multivariate analyses (clustering and ordering) to discriminate the trilobite associations within 67 different samples. Three previously known communities and one new were recognised: the Eifelian Mixed association, the Givetian Dechenella association and the two Frasnian Bradocryphaeus and Scutellum-Goldius associations. These trilobite faunas present a progressive ecological specialisation. The Mixed association occurs both in the ramp or carbonated (local reef developed on the ramp) facies without any significant difference in its composition. The Dechenella fauna occurs preferentially close to barrier reefs, but can also survive during short periods of detrital input. The two Frasnian communities show a strong relationship with their environment. The Scutellum-Goldius association is only found in reef systems, whereas the Bradocryphaeus flourishes exclusively in lateral facies.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Faunal dynamics across the Silurian-Devonian positive isotope excursions (delta13C, delta18O) in Podolia, Ukraine: Comparative analysis of the Ireviken and Klonk events
Autorzy:
Racki, G.
Balinski, A.
Wrona, R.
Malkowski, K.
Drygant, D.
Szaniawski, H.
Powiązania:
https://bibliotekanauki.pl/articles/20924.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fauna dynamics
Silurian
Devonian
isotope excursion
Podolia
Ukraine
comparative analysis
Ireviken event
Klonk event
Brachiopoda
Conodonta
Chitinozoa
carbon isotope
oxygen isotope
geochemistry
Opis:
Two global isotopic events, the early Sheinwoodian (early Wenlock) and that at the Silurian–Devonian transition, have been comprehensively studied in representative carbonate successions at Kytayhorod and Dnistrove, respectively, in Podolia, Ukraine, to compare geochemistry and biotic changes related correspondingly to the Ireviken and Klonk events. These two large−scale isotope excursions reveal different regional ecosystem tendencies. The well−defined increasing trend across the Llandovery–Wenlock boundary in siliciclastic input, redox states and, supposedly, bioproductivity, was without strict correlative relations to the major ¹³C enrichment event. The environmental and biotic evolution was forced by eustatic sea−level fluctuations and two−step climate change toward a glaciation episode, but strongly modified by regional epeirogeny movements due to location near the mobile Teisseyre−Törnquist Fault Zone. Thus, the global early Sheinwoodian biogeochemical perturbation was of minor depositional significance in this epeiric sea, as in many other Laurussian domains. Conversely, the Podolian sedimentary record of the Klonk Event exhibits temporal links to the abrupt δ¹³C anomaly, overprinted by a tectonically driven deepening pulse in the crucial S–D boundary interval. This carbon cycling turnover was reflected in the regional carbonate crisis and cooling episodes, paired with a tendency towards eutrophication and recurrent oxygen deficiency, but also with major storms and possible upwelling. Faunal responses in both Podolian sections follow some characters of the Silurian pattern worldwide, as manifested by conodont changeover prior to the major early Sheinwoodian isotopic/climatic anomaly. This contrasts with the relative brachiopod and chitinozoan resistances in the course of the Ireviken Event. Also, during the Klonk Event, a moderate faunal turnover, both in benthic and pelagic groups, occurred only near the very beginning of the prolonged ¹³C−enriched timespan across the system boundary, possibly due to progressive dysoxia and temperature drop. The characters point to a peculiarity of the Klonk Event by comparison with the Silurian global events, and some similarity already to the succeeding Devonian transgressive/anoxic episodes.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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