Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "wyspy" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Early Pliocene calcareous and siliceous microfossils of the Sawai Bay Formation, Car Nicobar Island, northern Indian Ocean
Autorzy:
Chakraborty, Arindam
Ghosh, Amit K.
Mccartney, Kevin
Saxena, Stuti
Dey, Rikee
Roy, Lopamudra
Powiązania:
https://bibliotekanauki.pl/articles/1835597.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Zanclean
calcareous nannofossils
radiolarians
diatoms
silicoflagellates
sponge spicules
Andaman islands
Nicobar islands
India
nanoplankton wapienny
radiolarie
okrzemki
wyspy Andaman
wyspy Nicobar
Indie
Opis:
The present contribution provides a study of calcareous nannofossils and siliceous microfossils from the Sawai Bay Formation on Car Nicobar Island, northern Indian Ocean. Two stratigraphically short sediment intervals near Sawai Bay have been examined. Qualitative and quantitative microfossil analyses show the Sawai Bay ‘A’ Section to be devoid of siliceous microfossils, while 24 well-preserved calcareous nannofossil taxa are identified. The Sawai Bay ‘B’ Section yields 18 calcareous nannofossil, 33 radiolarian and 25 diatom taxa. The calcareous nannofossil index taxa (Ceratolithus armatus Müller, 1974a and C. cristatus Kamptner, 1950) indicate both sections to be from zones NN12 (CN10b) and NN13 (CN10c) of early Pliocene (Zanclean) age. The radiolarian taxa, i.e., Didymocyrtis avita Riedel, 1953, Euchitonia spp., Siphocampe lineata (Ehrenberg) Nigrini, 1977, Stichocorys peregrina Riedel, 1953, Semantis spp. and Stylochlamydium sp. are common in the Sawai Bay ‘B’ Section, which is assigned to Zone RN9. Most of the diatom taxa are represented by rep-resentatives of the genera Actinocyclus Ehrenberg, 1837, Azpeitia Peragallo in Tèmpere and Peragallo, 1912, Coscinodiscus Ehrenberg, 1839a, Grammatophora Ehrenberg, 1841 and Triceratium Ehrenberg, 1839b, with the benthic diatom species Triceratium favus Ehrenberg, 1839b being predominant (~35% of the total diatom count). Siliceous microfossils are also represented by silicoflagellates dominated by Dictyocha spp. and sponge spicules dominated by astrophorids.
Źródło:
Acta Geologica Polonica; 2021, 71, 2; 175-198
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stem chondrichthyan microfossils from the Lower Old Red Sandstone of the Welsh Borderland
Autorzy:
Burrow, C. J.
Turner, S.
Powiązania:
https://bibliotekanauki.pl/articles/138801.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
scale histology
palaeobiogeography
Lower Devonian
Lochkovian
stem gnatho stomes
Altholepis
Polymerolepis
British Isles
histologia
paleobiogeografia
dewon dolny
lochkov
Wyspy Brytyjskie
Opis:
Placoid and polyodontode scales of stem chondrichthyans have been found in the early Lochkovian “Ditton Group” of the Brown Clee Hill district, Shropshire, England and at Talgarth, south Wales. One of the forms is assigned to a new species of Altholepis Karatajūtė-Talimaa, 1997, a genus already recognised from Lochkovian shallow marine deposits in Celtiberia, Spain and the Northwest Territories, Canada as well as the type locality in Podolia, Ukraine. Altholepis salopensis sp. nov. is based on small polyodontode scales with typically three to eight high odontodes; the scale form was previously considered to belong to acanthodian “Nostolepis” robusta (Brotzen, 1934). The structure of other scales formerly assigned to “Nostolepis” robusta has led us to erect a new genus Jolepis for this scale form, which differs from Altholepis in lacking an ordered layout of odontodes. Jolepis robusta (Brotzen, 1934), originally (and possibly still) considered to be an acanthodian, is also known from the Baltic countries, Russia, and northern Germany (ex erratic limestones). Scales of acanthodian Parexus recurvus Agassiz, 1845, and/or possibly from the stem chondrichthyan Seretolepis elegans Karatajūtė-Talimaa, 1968 (scales of these two taxa are barely distinguishable), and of stem chondrichthyan Polymerolepis whitei Karatajūtė-Talimaa, 1968 are also present. Altholepis, Jolepis gen. nov., Seretolepis Karatajūtė-Talimaa, 1968 and Polymerolepis KaratajūtėTalimaa, 1968 are found in marine deposits elsewhere; the British occurrence of these taxa adds to the debate on the sedimentological origins of the Lower Old Red Sandstone deposits in the Welsh Borderland. The geographic range of several early sharks is now known to extend around the Old Red Sandstone continent and beyond.
Źródło:
Acta Geologica Polonica; 2018, 68, 3; 321-334
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies