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    Wyświetlanie 1-9 z 9
    Tytuł:
    Coexistence of algae and a graptolite-like problematicum: a case study from the late Silurian of Podolia (Ukraine)
    Autorzy:
    Skompski, Stanisław
    Kozłowski, Wojciech
    Łuczyński, Piotr
    Kozłowska, Anna
    Powiązania:
    https://bibliotekanauki.pl/articles/27323966.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    Dasycladales
    Graptolite-like epibionts
    Silurian
    Ludlow
    Ukraine
    periti dal environment
    glony
    graptolity
    epibionty
    sylur
    ludlow
    Ukraina
    Opis:
    This contribution presents the record of an abundant assemblage of well-preserved, thallophytic noncalcified algae and of an epibiotic form that has been recognised as a putative graptolite from the upper Silurian (Ludlow, Gorstian–Ludfordian) of Podolia (western part of Ukraine). The sediments represent a shallow peritidal zone of the shelf. A new genus and species, Voronocladus dryganti, belonging to the Dasycladales Pascher, 1931, is established. Most of the specimens representing the algal thallus are overgrown by problematical epibiotic graptolites, described as Podoliagraptus algaeoides gen. et sp. nov. This phenomenon is explained as an epiphytic mode of life of the putative graptolite on algae, and is herein compared to recently known coexistences of algae with other organisms. The excellent state of preservation, and the abundance of studied Dasycladales algae and epibiotic problematics indicate that the investigated mudstone layer can be treated as a ‘Konservat Lagerstätte’ sensu Seilacher (1970).
    Źródło:
    Acta Geologica Polonica; 2023, 73, 2; 115--133
    0001-5709
    Pojawia się w:
    Acta Geologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evolution of retiolitid graptolites - a synopsis
    Autorzy:
    Kozlowska-Dawidziuk, A
    Powiązania:
    https://bibliotekanauki.pl/articles/23196.pdf
    Data publikacji:
    2004
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Holoretiolites
    Ludlow
    Retiolitidae
    retiolitid graptolite
    paleobiology
    Silurian
    evolution
    Graptoloidea
    paleontology
    rhabdosome reduction
    Opis:
    Twenty million years of retiolitid evolution reflect environmental changes, the most severe being the Silurian Cyrtograptus lundgreni Event. Five biostratigraphically and morphologically constrained retiolitid faunas are distinguished and characterized according to their rhabdosomal modifications: (1) the oldest and long−ranging Llandovery group of mostly large and morphologically complex rhabdosomes, (2) the less diverse Telychian−Sheinwoodian group, (3) the Cyrtograptus lundgreni Biozone varied group of intermediate size, and two short−ranged (4) late Homerian, and (5) early Ludlow groups with small rhabdosomes. Although the evolutionary history of retiolitids was complex and not linear, a common tendency toward reduction of rhabdosome size in most lineages is observed. The greatest reduction in both number and volume of thecae, and in skeletal elements is demonstrated in the Gothograptus and Plectograptusfaunas. Contrary to the thecal decrease, a distinctive increase of sicula size is observed in retiolitids. Two types of colonies are distinguished: L−colonies with a small sicula and numerous large thecae of similar size, and S−colonies with a long sicula and a few, small thecae. These changes imply modification of the soft body: an increase in siculozooid length and a decrease in the size of the zooids. Thus, the siculozooid probably produced great amounts of morphogen inhibiting zooid growth. In consequence the phenomenon of colony reduction occurred. The most extreme stages of rhabdosome reduction in Ludlow retiolitids can be seen in Plectodinemagraptus gracilis of the Plectograptuslineage and in the new species Holoretiolites helenaewitoldi, possibly representing the last stage of skeletal reduction in the Gothograptus lineage; the next hypothetical stage would be its total loss. The sicula length of Holoretiolites, about 2 mm, is reported herein for the first time.
    Źródło:
    Acta Palaeontologica Polonica; 2004, 49, 4
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Adaptive radiation of monograptids after the Late Wenlock crisis
    Autorzy:
    Koren, T N
    Urbanek, A
    Powiązania:
    https://bibliotekanauki.pl/articles/22957.pdf
    Data publikacji:
    1994
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    sylur
    fauna graptoloidowa
    Pristiograptus dubius
    ewolucja
    wymieranie gatunkow
    skamienialosci
    monograptidy
    ludlow
    paleontologia
    wenlok
    Opis:
    Succession of late Wenlock graptolites in the Kursala Formation, Tien Shan (Kirghizia), documents of the early recovery phase after the global C. lundgreni Event. Pristiograptus dubius was the only survivor among monograptids. After displaying a mass occurrence and an increased variation, the P. dubius stem lineage splits into two main trends: line A, represented by Pristiograptus idoneus and line B, represented by Colonograptus? praedeubeli. The former leads to Lobograptus? sherrardae, a generalized forerunner of such diverse trends as linograptids, cucullograptids and possibly also neocucullograptids (via Bohemograptus). The latter initiates the Colonograptus-Saetograptus line. The P. idoneus - L.? sherrardae lineage shows distinct gracilization, an apomorphic feature, while the other one preserves ancestral robustness, a plesiomorphic character. Hence, the bulk of the later monograptids of Gorstian and Ludfordian age may be derived from the P. dubius stem lineage. In respect of this conservative lineage a non-cladistic approach is prefered, because its morphological spectrum and evolutionary potential, and as we believe its specific identity, were preserved, in spite of numerous speciation events, until the early Pridoli.
    Współczesne badania nad kryzysem biotycznym jaki dotknął monograptidy w późnym wenloku (tzw. zdarzenie C. lundgreni), pozwalają ocenić zarówno skalę masowego wymierania (przeżywa tylko jeden gatunek, Pristiograptus dubius), jak i przebieg procesów składających się na wczesny etap odradzania fauny graptoloidowej. Duże znaczenie dla poznania tych ostatnich miało zbadanie obfitej fauny z formacji Kursala, w górach Tien Szań (Kyrgystan). Różnicowanie się szczepu Pristiograptus dubius było poprzedzone jego masowym występowaniem i zwiększoną zmiennoscią. Następnie doszło do oddzielenia się dwu głównych linii ewolucyjnych: linii A, reprezentowanej przez P. idoneus oraz linii B, którą wyznacza pojawienie się Colonograptus? praedeubeli. Pierwszy gatunek dał początek Lobograptus? sherrardae, stanowiącemu wspólnego przodka tak rozbieżnych trendów ewolucyjnych jak linograptidy (Neodiversograptus nilssoni), kukullograptidy (Lobograptus progenitor), a prawdopodobnie także neokukullograptidy (za pośrednictwem Bohemograptus). Natomiast C.? praedeubeli, przedstawiciel lini B, zapoczątkowuje rozwój charakterystycznych dla wczesnego ludlowu monograptidów "kolczastych" (Colonograptus, Saetograptus). Rozejście się wspomnianych linii ewolucyjnych określone jak "wczesna schizma", wyznacza zarazem główne kierunki ewolucji monograptidów ludlowu.
    Źródło:
    Acta Palaeontologica Polonica; 1994, 39, 2; 137-167
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Late Variscan deformation events in the Bardo Syncline revealed by biotite K-Ar dating of Ludlow-age tuffite (Holy Cross Mountains, Poland)
    Autorzy:
    Wójcik, Emil
    Pacek, Adrian
    Pelc, Andrzej
    Powiązania:
    https://bibliotekanauki.pl/articles/2058714.pdf
    Data publikacji:
    2021
    Wydawca:
    Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
    Tematy:
    Niewachlów tuffites
    biotite deformation dating
    illite-smectite
    Ludlow
    Daleszyce Fault Zone
    Holy Cross Fold Belt.
    Opis:
    n the Bardo Syncline (Holy Cross Mountains, Poland), two beds of tuffite (named the Niewachlów tuffites) have been discovered within greywackes of Ludlow (Silurian) age. K-Ar dating of the lower bed yielded an age of 292.8 ±4.0 Ma, while the upper bed provided an age of 341.9 ±4.3 Ma. The dates pertain to metamorphic alteration of the tuffite, related to reactivation of the Daleszyce Fault Zone. In this zone, biotite crystals present in the foliation zones were recrystallized and their K-Ar isotopic system was rejuvenated in a temperature range of ~270–300°C. The dates that were obtained define the ages of two tectono-metamorphic episodes and reflect the timing of displacements along the fault which, in turn, reflect two deformation phases during the Variscan Orogeny (Mississippian and Early Permian). Moreover the dates may be correlated with Late Variscan magmatic activity in the Holy Cross Mountains and adjacent areas. The deformation of the Daleszyce Fault Zone may be regarded as resulting from displacements of lithospheric blocks within the Trans European Suture Zone during the Late Variscan reconstruction of the Baltica palaeocontinent margin.
    Źródło:
    Geological Quarterly; 2021, 65, 1; 15
    1641-7291
    Pojawia się w:
    Geological Quarterly
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Late Caradoc and early Ludlow Radiolaria from Baltic erratic boulders
    Autorzy:
    Gorka, H
    Powiązania:
    https://bibliotekanauki.pl/articles/20279.pdf
    Data publikacji:
    1994
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    karadok
    sylur
    Baltyk
    ordowik
    skamienialosci
    ludlow
    glazy narzutowe
    wapien baltycki
    szkielet
    paleontologia
    Radiolaria
    mikroorganizmy kopalne
    Opis:
    Glacial erratic boulders of the Ostseekalk type, late Caradoc in age, contain spumellarian radiolarians with their skeleton substituted by iron minerals secondarily oxidized to goethite. Species of both the Inaniguttidae, characterized by the presence of a small spherical central shell, and Entactiniidae, with a transverse central bar, have been identified. A similar radiolarian assemblage, but with original siliceous skeletons preserved, has been identified in a graptolitic lirnestone boulder, early Ludlow in age.
    Opracowano Radiolaria (Polycystina) z ordowickich i sylurskich głazów narzutowych regionu bałtyckiego. Ordowickie głazy narzutowe, to tak zwany "wapień bałtycki", którego wiek określa się na późny karadok. Zawarte w nich szkielety Radiolaria są zlimonityzowane lub spirytyzowane, co jest częstym zjawiskiem w przypadku tej grupy mikroorganizmów kopalnych. Przedstawiono historię badań nad skamieniałościami zawartymi w wapieniu bałtyckim ze szczególnym uwzględnieniem prac polskich autorów oraz nad Radiolariami z ordowickich i sylurskich osadów.
    Źródło:
    Acta Palaeontologica Polonica; 1994, 39, 2; 169-179
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Silurian retiolitid graptolite Plectograptus: New observations and new species
    Autorzy:
    Bates, D.E.B.
    Kozlowska, A.
    Maletz, J.
    Kirk, N.H.
    Lenz, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/20525.pdf
    Data publikacji:
    2006
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Graptoloidea
    Plectograptus
    Retiolitidae
    rhabdosome
    Silurian
    graptolite
    new species
    paleontology
    retiolitid graptolite
    Ludlow
    morphology
    terminology
    systematics
    Opis:
    The Ludlow genus Plectograptus, with the type species Retiolites macilentus Törnquist, 1887, collected from Thuringia (Germany), has been a widely−identified, monospecific, but poorly understood taxon for almost one hundred years. This was due to poor and incomplete preservation of the type material, and misidentification by subsequent authors up to 1995. The original, and only, type specimen of P. macilentus collected by Törnquist being lost, a neotype is herein selected from a small collection of Thuringian material. The genus has now been redefined and based on this, and SEM studies of isolated material, the defining characteristics of the genus are (i) the possession of a simple ancora umbrella with five radial lists with an incompletely developed rim; (ii) an ancora umbrella separated from lateral ancora sleeve walls by exceptionally large lateral orifices; (iii) the possession of mid−ventral lists; (iv) simple, orderly zigzag lateral wall ancora sleeve lists. Recently, two additional species, P. robustus and P. wimani, previously placed in different genera, were assigned to Plectograptus. This study recognizes three new species: P. mobergi, P. toernquisti, and P. trijunctus, bringing the total number of species to six. Species are distinguished by the presence or absence of genicular processes, inclination of the thecal ventral walls and mid−ventral lists, presence or absence of reticular lists, and three−way or four−way sleeve/lateral rod/apertural lip junctions.
    Źródło:
    Acta Palaeontologica Polonica; 2006, 51, 3
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evolution of the retiolitid Neogothograptus [Graptolithina] and its new species from the upper Wenlock of Poland, Baltica
    Autorzy:
    Kozlowska, A
    Lenz, A.
    Melchin, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/20789.pdf
    Data publikacji:
    2009
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    evolution
    retiolitid
    Neogothograptus
    Graptolithina
    new species
    Upper Wenlock
    Polska
    Wenlock
    Ludlow
    Silurian
    Retiolitidae
    Gothograptus
    biostratigraphy
    ocean current
    Colonograptus praedeubeli
    Lobograptus progenitor
    Neogothograptus reticulatus
    Opis:
    Neogothograptus reticulatus sp. nov. from the upper Homerian Colonograptus praedeubeli Biozone, and N. thorsteinssoni and N. alatiformis from the Lobograptus progenitor Biozone, are described for the first time from three localities: borehole, Baltic erratic boulder of East European Platform and Holy Cross Mountains of Poland. N. reticulatus, presently the oldest known species of Neogothograptus, is also tentatively identified from upper Homerian strata of southeastern Australia. The two other species are previously known only from Arctic Canada, and possibly China. The morphology of the Neogothograptus reticulatus rhabdosome, its appendix, thecal profile, densely reticulated rhabdosome and genicular hoods suggest a close relationship to N. eximinassa from Colonograptus ludensis Biozone. N. reticulatus and N. eximinassa are most similar to Gothograptus nassa, the earliest−known retiolitid to appear immediately following the Cyrtograptus lundgreni extinction event. The biostratigraphic position of N. reticulatus suggests it might be considered as a potential ancestor to all younger (Ludlow) species of Neogothograptus. Cladistic analysis, however, provides no direct support for such an interpretation and, instead, suggests that Baculograptus batesi may be the ancestor. The occurrences of Neogothograptus, as well as G. nassa, from a number of Silurian terranes mostly from low paleolatitude regions, but also from high paleolatitudes, demonstrate their tolerance to a broad range of paleoenvironments.
    Źródło:
    Acta Palaeontologica Polonica; 2009, 54, 3; 423-434
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Silurian aphrosalpingid sphinctozoans from Alaska and Russia
    Autorzy:
    Rigby, J K
    Nitecki, M.H.
    Soja, C.M.
    Blodgett, R.B.
    Powiązania:
    https://bibliotekanauki.pl/articles/23278.pdf
    Data publikacji:
    1994
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    fauna kopalna
    Aphrosalpingidae
    sylur
    gabki kopalne
    skamienialosci
    Aphrosalpinx nana
    Cystothalamiella alaskensis
    Nematosalpinx hormathodes
    Cystothalamiella irregularis
    ludlow
    cechy morfologiczne
    dendroklony
    sfinktozoa
    Alaska
    szkielet
    paleontologia
    gabki
    formacja Haceta
    trikranoklony
    Źródło:
    Acta Palaeontologica Polonica; 1994, 39, 4; 341-391
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Marine snow and epipelagic suspensoids in the Reda carbonates and a pronounced mid-Ludfordian (Silurian) CIE in the axis of the Baltic Basin (Poland)
    Autorzy:
    Kozłowski, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1835581.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    pelagic carbonates
    Sparoids
    marine snow
    algal blooms
    eolian dust
    carbonate supersaturation
    euxinia
    Baltic basin
    Reda Member
    ludlow
    Silurian
    węglany pelagiczne
    sparoidy
    śnieg morski
    zakwit glonów
    osady eoliczne
    basen bałtycki
    sylur
    Opis:
    The mid-Ludfordian pronounced, positive carbon isotope excursion (CIE), coincident with the Lau/kozlowskii extinction event, has been widely studied so far in shallow-water, carbonate successions, whereas its deep-water record remains insufficiently known. The aim of this research is to reconstruct the sedimentary environments and the palaeoredox conditions in the axial part of the Baltic-Podolian Basin during the event. For these purposes, the Pasłęk IG-1 core section has been examined using microfacies analysis, framboid pyrite diameter and carbon isotope measurements. The prelude to the event records an increased influx of detrital dolomite interpreted as eolian dust, coupled with a pronounced decrease in the diameter of the pyrite framboids, indicating persistent euxinic conditions across the event. The event climax is recorded as the Reda Member and consists of calcisiltites, composed of calcite microcrystals (‘sparoids’), which are interpreted as suspensoids induced by phytoplankton blooms in the hipersaturation conditions present in the epipelagic layer of the basin. Both the prelude and climax facies show lamination, interpreted as having resulted from periodical settling of marine snow, combined with hydraulic sorting within a ‘benthic flocculent layer’, which additionally may be responsible for a low organic matter preservation rate due to methanogenic decomposition. Contrary to the observed basinward CIE decline in the benthic carbonates in the basin, the Reda Member records an extremely positive CIE (up to 8.25‰). Given the pelagic origin of the sparoids, the CIE seems to record surface-water carbon isotope ratios. This points to a large carbon isotope gradient and kinetic fractionation between surface and bottom waters during the mid-Ludfordian event in a strongly stratified basin. The Reda facies-isotope anomaly is regarded as undoubtedly globally triggered, but amplified by the stratified and euxinic conditions in the partly isolated, Baltic-Podolian basin. Hence, the common interpretation of the basin record as representative for the global ocean needs to be treated with great caution.
    Źródło:
    Acta Geologica Polonica; 2020, 70, 4; 529-567
    0001-5709
    Pojawia się w:
    Acta Geologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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