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Wyszukujesz frazę "radiolaria" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Applications and limitations of micro-XCT imaging in the studies of Permian radiolarians: a new genus with bi-polar main spines
Autorzy:
XIAO, YIFAN
SUZUKI, NORITOSHI
HE, WEIHONG
Powiązania:
https://bibliotekanauki.pl/articles/945632.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
radiolaria
taxonomy
micro-xct
permian
changhsingian
china
Opis:
Microfocus X-ray Computed Tomography (micro-XCT) has been employed recently in radiolarian studies, though so far primarily to generate high quality tomographic images. Although micro-XCT technique cannot always produce high-quality tomographic images, it frequently can provide valuable information on the internal structure of spongy polycystines. Here we employ micro-XCT to understand internal skeletal structures of several Permian specimens of polycystine radiolarians. Structural inferences from micro-XCT images are compared to images of the same specimens made with SEM and transmitted light microscopy (TLM). The utility of micro-XCT for imaging internal structures is first confirmed by examining the spongy, flat, four-spined species Tetraspongodiscus stauracanthus. Micro-XCT method is then used to examine the internal structures of a spherical to elliptical polycystine with two bi-polar main spines, Dalongicaepa bipolaris Xiao and Suzuki gen. et sp. nov., from the Dalong Formation (Changhsingian) of South China. The new genus is characterized by four to seven densely concentric shells with a large spherical hollow in the center and two cylindrical spines at both poles of the cortical shell, and belongs to the family Spongotortilispinidae. Spherical to elliptical polycystines with bi-polar main spines are similar in external appearance, and their phylogenetic relationships are only determinable by examination of the internal structures. We therefore analyzed all Permian and Mesozoic spherical to elliptical polycystines with bi-polar main spines showing internal structures, using cluster analysis to measure similarity. The results show distinctive differences in internal structures and suggest that family level relationships should be revised in the future.
Źródło:
Acta Palaeontologica Polonica; 2017, 62, 3; 647-656
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early Oxfordian Radiolaria from Zalas quarry, Kraków Upland, South Poland
Wczesnooksfordzkie promienice z kamieniołomu w Zalasie, Wyżyna Krakowska, Polska południowa
Autorzy:
Górka, H.
Bąk, M.
Powiązania:
https://bibliotekanauki.pl/articles/191266.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
early Oxfordian
radiolaria
Kraków Upland
biostratigraphy
taxonomy
palaeoecology
Opis:
This paper presents preliminary research on radiolarian faunas from the Upper Jurassic deposits of the Kraków Upland (South Poland) carried at Zalas quarry. The systematic description of twenty-five species of Radiolaria from the lower Oxfordian deposits has been presented herein. The species belong to the orders Nassellaria (16 species) and Spumellaria (9 species). In number of specimens, the assemblage is dominated by spumellarians. The radiolarians show features of Boreal faunas, influenced by Tethyan realm. The assemblage has been correlated with cordatum ammonitic subzone (early Oxfordian).
W pracy przedstawiono wstępne wyniki badań promienic (Radiolaria) z utworów górnej jury, prowadzonych na Wyżynie Krakowskiej w kamieniołomie w Zalasie. Przedstawiono opis systematyczny 25 gatunków promienic z dolnego oksfordu. Spośród opisanych form 16 reprezentuje rząd Nassellaria, a 9 należy do rzędu Spumellaria. Pod względem liczby okazów, w zespole przeważają przedstawiciele rzędu Spumellaria. Promienice reprezentują faunę borealną, która żyła w środowisku o znacznym wpływie morza tetydzkiego. Analizowany zespół promienic został skorelowany z podpoziomem amonitowym cordatum (wczesny oksford).
Źródło:
Annales Societatis Geologorum Poloniae; 2000, 70, 2; 165-179
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New data on the age and stratigraphic relationships of the Czajakowa Radiolarite Formation in the Pieniny Klippen Belt (Carpathians) based on the radiolarian biostratigraphy in the stratotype section
Autorzy:
Bąk, M.
Chodacka, S.
Bąk, K.
Okoński, S.
Powiązania:
https://bibliotekanauki.pl/articles/139119.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Middle-Late Jurassic
radiolaria
taxonomy
biostratigraphy
Czajakowa Radiolarite Formation
pelagic siliceous facies
Pieniny Klippen Belt
Carpathians
jura
promienica
taksonomia
biostratygrafia
Czajakowa Skała
radiolaryty z Czajakowej
Pieniński Pas Skałkowy
Karpaty
Opis:
The radiolarian biostratigraphy of the Middle–Upper Jurassic pelagic siliceous sediments (Czajakowa Radiolarite Formation) in the Niedzica succession of the Pieniny Klippen Belt (Carpathians) is interpreted in terms of their age in a stratotype section, and facies equivalents in other tectonic-facies units of this region. The siliceous sediments are represented by radiolarian cherts and silicified limestones which are underlain and overlain by red nodular limestones, equivalents of the Rosso Ammonitico facies. The radiolarian association includes thirty-seven taxa belonging to twenty one genera which represent the Northern Tethyan Palaeogeographic Province. Key radiolarians recorded provide a means of correlation with zonation schemes based on Unitary Associations defined for the Jurassic Tethyan sediments. The age of the Czajakowa Radiolarite Formation in the stratotype section is determined as U.A.Z.9 to U.A.Z.11 corresponding to middle Oxfordian up to Kimmeridgian. Comparison of radiolarian biozones from the stratotype section with other facial equivalent sections in the Pieniny Klippen Belt reveals a significant diachronism for both the lower and the upper limits of the Jurassic pelagic siliceous facies.
Źródło:
Acta Geologica Polonica; 2018, 68, 1; 1-20
0001-5709
Pojawia się w:
Acta Geologica 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 1-4 z 4

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