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Wyświetlanie 1-2 z 2
Tytuł:
Tidally dominated Miocene deltaic deposits and pipe rocks in the Tebessa Basin, eastern Algeria: sedimentological and ichnological characteristics
Autorzy:
Mazrou, Samia
Mahboubi, Mohamed
Powiązania:
https://bibliotekanauki.pl/articles/1841620.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
delta
palaeoenvironments
Skolithos
Langhian–Tortonian
North Africa
paleośrodowisko
Lang
Torton
Afryka Północna
Opis:
Analyses of sedimentology, ichnology and depositional environments of Langhian–Tortonian siliciclastic deposits in the southern Tebessa Basin (eastern Algeria) have revealed a tidally dominated deltaic setting with a high concentration of vertical burrows. From south to north, two depositional environments are here distinguished in the Tebessa Basin: a subaerial lower delta plain in the Oum Ali region with the trace fossils Ophiomorpha and Skolithos linearis, and a proximal delta front with numerous Skolithos, situated in the Hjer Essefra area. The occurrence of Skolithos pipe rock in this Miocene subtidal domain is unusual. Pipe rocks have been commonly reported from shallow and well-oxygenated environments, especially from Cambrian strata; their number decreased significantly during the Ordovician, coupled with an increase in biodiversity. Here different deltaic subenvironments and tidal signals that are exceptionally well preserved in outcrops are analysed and interpreted. Different ichnotaxa are briefly described, and the uncommon density and size of Skolithos pipe-rock in these Miocene strata are discussed.
Źródło:
Geologos; 2021, 27, 1; 15-34
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ornamentation of dermal bones of Placodermi from the Lower Devonian of Morocco as a measure of biodiversity
Autorzy:
Antczak, M.
Berkowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/94702.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
Arthrodira
interspecific variation
ontogeny
fishes
North Africa
zróżnicowanie międzygatunkowe
ontogeneza
ryby
Afryka Północna
Opis:
Dermal bones are formed early during growth and thus constitute an important tool in studies of ontogenetic and evolutionary changes amongst early vertebrates. Ornamentation of dermal bones of terrestrial vertebrates is often used as a taxonomic tool, for instance in Aetosauria, extant lungfishes (Dipnoi) and ray-finned fishes (Actinopterygii), for which it have been proved to be of use in differentiating specimens to species level. However, it has not been utilised to the same extent in placoderms. Several features of the ornamentation of Early Devonian placoderms from Hamar Laghdad (Morocco) were examined using both optical and scanning electron microscopy to determine whether it is possible to distinguish armoured Palaeozoic fishes. Four distinct morphotypes, based on ornamentation of dermal bones, are dif-ferentiated. These distinct types of ornamentation may be the result of either different location of dermal plates on the body or of ontogenetic (intraspecific) and/or interspecific variation.
Źródło:
Geologos; 2017, 23, 2; 65-73
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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