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    Wyświetlanie 1-5 z 5
    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:
    Early and Middle Frasnian brachiopod faunas and turnover on the South China shelf
    Autorzy:
    Ma, X -P
    Becker, R.T.
    Li, H.
    Sun, Y.-Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/21029.pdf
    Data publikacji:
    2006
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Early Frasnian
    Middle Frasnian
    Frasnian
    paleontology
    brachiopod fauna
    South China shelf
    Devonian
    Brachiopoda
    Cyrtospirifer
    faunal turnover
    Opis:
    The first appearance of the brachiopod Cyrtospirifer and related forms in the Late Devonian of South China significantly postdates the beginning of the Frasnian and the entry of the group in other parts of the world. Scattered data from different sections suggest that its first entry, associated with the emergence of other plicate spiriferids, such as theodossid and conispiriferid brachiopods, was late in the Middle Frasnian. At the same time, many rhynchonellids disappeared or became extinct locally in South China. This brachiopod faunal overturn near the Palmatolepis punctata–Early Pa. hassi zonal boundary is the most significant event in the Early–Middle Frasnian of South China, characterized by about a 35% loss of existing species and the flourishing of the plicate spiriferids, which was coeval with the end of a major biogeochemical perturbation recently recognized in the Pa. punctata Zone. By contrast, atrypid brachiopods do not seem to show any significant diversity change. The brachiopod faunal change was probably related to a (local?) transgressive event in South China, which also brought new pelagic faunas northwards into some intra−shelf deeper water areas, such as the Shetianqiao area in central Hunan Province. Fifteen brachiopod species are described and illustrated, which include some taxa that are first recorded or recognized in South China, e.g., the spiriferid Pyramidaspirifer, which is now known from both North America and South China. One new species, Desquamatia qiziqiaoensis, is erected.
    Źródło:
    Acta Palaeontologica Polonica; 2006, 51, 4; 789-812
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conodont-based event stratigraphy of the Early-Middle Frasnian transition on the South Polish carbonate shelf
    Autorzy:
    Pisarzowska, A
    Sobstel, M.
    Racki, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/22673.pdf
    Data publikacji:
    2006
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    conodont association
    stratigraphy
    Early-Middle Frasnian
    Frasnian
    Polska
    carbonate shelf
    biostratigraphy
    carbon isotope
    paleoecology
    Devonian
    Palmatolepis transitans
    Palmatolepis punctata
    Opis:
    Early to Middle Frasnian (E–MF) epicontinental sequences are investigated in five representative localities of the Holy Cross Mountains and Cracow region, with emphasis on conodont biostratigraphy, to evaluate the regional stratigraphic and biotic context of a major biogeochemical perturbation in global carbon cycling. Conodont associations from the Palmatolepis transitans to Palmatolepis punctata Zone boundary beds are dominated by the shallow−water polygnathid and ancyrodellid fauna in the South Polish epicontinental successions, and first appearances of index palmatolepid species are delayed due to facies control of pelagic environments during intermittent drowning of the carbonate shelf. Thus, identification of the zonal boundary is based mainly on species of Ancyrodella, and five distinctive ancyrodellid levels in the succession across the E–MF interval enable refined correlation of the sections studied, especially when paired with chemostratigraphic proxies. Prominent conodont biofacies shifts coincided with eustatic deepening, which is correlated with the Timan, Middlesex, and early Rhinestreet events, respectively. Trends in the conodont dynamics, mortality and diversity, partly replicated by the benthic biota (especially shelly faunas and crinoids), indicate that the faunal turnovers correlate also with the main δ¹³C excursions and related changes in trophic conditions. The E–MF transitional interval, marked by short−term sea−level fluctuations, is distinguished by a change from relatively diversified biofacies to more homogenous, mostly impoverished faunas. The latter change is a biotic response to the beginning of a prolonged (ca. 0.5 Ma) positive δ¹³C anomaly, probably paired with unsteady eutrophic and partly anoxic regimes. The late Pa. punctata Zone negative carbon isotope anomaly is synchronous with the second large−scale pelagic biofacies remodelling, including mesotaxid extinction. A stabilization of the carbon cycle and its return to normal background values at the start of the Early Palmatolepis hassi Zone coincide with conodont biofacies diversification and recovery of reef−related biofacies. With the exception of collapsed, endemic Kadzielnia−type mud−mound biota and a moderate biodiversity depletion due to overall ecosystem stagnation, no significant extinction events can be demonstrated, even if the large−scale changes in carbon cycling during the E–MF timespan are of higher−amplitude than the celebrated carbon isotopic anomalies related to the Frasnian–Famennian mass extinction. Thus, this regional succession in detail confirms that the large−scale punctata Isotopic Event (= Pa. punctata Event) is correlated neither with catastrophic enviromental nor radical biotic changes.
    Źródło:
    Acta Palaeontologica Polonica; 2006, 51, 4; 609-646
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluating the Frasnian-Famennian mass extinction: Comparing brachiopod faunas
    Autorzy:
    Copper, P
    Powiązania:
    https://bibliotekanauki.pl/articles/22494.pdf
    Data publikacji:
    1998
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    brachiopod fauna
    global loss
    Palmatolepis linguiformis
    climate cycle
    Palmatolepis rhenana
    Atrypida
    water setting
    mass extinction
    Brachiopoda
    South America
    Famennian
    shelf area
    Frasnian
    atrypid extinction
    Late Devonian
    Devonian
    reef habitat
    paleontology
    Opis:
    The Frasnian-Famennian (F-F) mass extinctions saw the global loss of all genera belonging to the tropically confined order Atrypida (and Pentamerida): though Famennian forms have been reported in the literafure, none can be confirmed. Losses were more severe during the Givetian (including the extinction of the suborder Davidsoniidina, and the reduction of the suborder Lissatrypidina to a single genus), but origination rates in the remaining suborder surviving into the Frasnian kept the group alive, though much reduced in biodiversity from the late Early and Middle Devonian. In the terminal phases of the late Palmatolepis rhenana and P. linguiformis zones at the end of the Frasnian, during which the last few Atrypidae dechned, no new genera originated, and thus the Atrypida were extirpated. There is no evidence for an abrupt termination of all lineages at the F-F boundary, nor that the Atrypida were abundant at this time, since all groups were in decline and impoverished. Atypida were well established in dysaerobic, muddy substrate, reef lagoonal and off-reef deeper water settings in the late Givetian and Frasnian, alongside a range of brachiopod orders which sailed through the F-F boundary: tropical shelf anoxia or hypoxia seems implausible as a cause for atrypid extinction. Glacial-interglacial climate cycles recorded in South America for the Late Devonian, and their synchronous global cooling effect in low latitudes, as well as loss of the reef habitat and shelf area reduction, remain as the most likely combined scenarios for the mass extinction events.
    Źródło:
    Acta Palaeontologica Polonica; 1998, 43, 2
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Siliceous biota [radiolarians and sponges] and the Late Devonian biotic crisis: The Polish reference
    Autorzy:
    Vishnevskaya, V
    Pisera, A.
    Racki, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/22703.pdf
    Data publikacji:
    2002
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Astroentactinia stellata
    Trilonche nigra
    Polska
    biotic crisis
    Astroentactinia paronae
    Trilonche echinata
    mass extinction
    taxonomy
    Famennian
    Frasnian
    siliceous fauna
    Late Devonian
    Devonian
    Radiolaria
    carbonate shelf
    Holy Cross Mountains
    Trilonche grandis
    paleoecology
    distribution
    paleontology
    Opis:
    The radiolarian species Astroentactinia paronae, A. stellata, Trilonche echinata, T. grandis, T. nigra, Haplentactinia inaudita, and H. rhinophyuosa are common in late Frasnian to early Famennian rhythmic, calcareous−marly sequence of the southern Holy Cross Mts., Poland. They are known also from coeval abundant siliceous biota assemblages from the carbonate shelf of East European Platform including more than 150 taxa of radiolarians. However, in ecological terms, the moderately diverse Polish microfaunas (34 species of 12 genera) are more similar to these from Kolyma and Alaska, also marked by abundance of sphaerical entactiniids and near−absence of bilateral−symmetric Ceratoikiscidae and Palaeoscenididae. A succession of two distinctive siliceous sponges associations is established in the incipiently submerged Holy Cross carbonate platform: from an ephemeral, diverse, mostly rigid−skeletal lithistid−hexactinosan foreslope assemblage (initial phase of the late Frasnian Kellwasser Crisis), to long−lasting, basinal loose−skeletal hexactinellid−demosponge faunas (appearing abundantly just prior the Frasnian–Famennian boundary in the late Palmatolepis linguiformis Zone). Such regional blooms of marine siliceous biotas, parallel to temporary retreat of calcareous biota, are demonstrated worldwide for the Kellwasser Crisis. These suggest probable causal links with cooling pulses and at least regional, volcanically induced eutrophication.
    Źródło:
    Acta Palaeontologica Polonica; 2002, 47, 2
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-5 z 5

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