Results 1 to 10 of about 2,126 (211)

Acritarchs of the Mesozoic of Ukraine [PDF]

open access: yesВісник Харківського національного університету імені В.Н. Каразіна. Серія Геологія. Географія. Екологія, 2021
Introduction. Acritarchs are one of the orthostratigraphic groups of microfossils that are widely used in Proterozoic and Paleozoic biostratigraphy.
Olena Shevchuk, Kateryna Ivanchenko
doaj   +3 more sources

Doushantuo-Pertatataka—Like Acritarchs From the Late Ediacaran Bocaina Formation (Corumbá Group, Brazil)

open access: yesFrontiers in Earth Science, 2021
Acritarchs, a polyphyletic group of acid-resistant organic-walled microfossils, dominate the eukaryotic microfossil record in the Proterozoic (2500–541 Ma) yet exhibit significant reduction in diversity and size at the transition to the Phanerozoic (541 ...
Ricardo Trindade   +2 more
exaly   +3 more sources

The evolution of reproduction in Ediacaran-Cambrian metazoans. [PDF]

open access: yesBiol Rev Camb Philos Soc
ABSTRACT The evolution of reproductive style is a fundamental aspect of metazoan life history but has not been explored holistically through the Ediacaran–Cambrian rise of metazoans. Recent molecular clock analyses based on only unequivocal metazoan fossil calibrations suggest that Porifera were present by at least 590 million years ago (Ma), all major
Wood RA, Droser ML.
europepmc   +2 more sources

Palaeoecology of Cambrian–Ordovician acritarchs from China: evidence for a progressive invasion of the marine habitats [PDF]

open access: yesPhilosophical Transactions of the Royal Society B: Biological Sciences, 2022
Thomas Servais   +2 more
exaly   +2 more sources

Global palaeogeographical implication of acritarchs in the Upper Ordovician [PDF]

open access: yesEstonian Journal of Earth Sciences, 2023
The Early–Middle Ordovician peri-Gondwana and Baltica acritarch provinces are easily recognizable, illustrating a clear provincialism of global phytoplankton.
Yan Kui   +4 more
doaj   +1 more source

Paleontological Evidence for Dinoflagellates and Ciliates as Early Eukaryotes

open access: yesJournal of Marine Science and Engineering, 2023
Molecular trees and geochemical markers suggest the divergence of dinoflagellates as early eukaryotes (~650 million years ago), but the traditional fossil record of cysts (dinocysts) starts during the Triassic (~230 million years ago). A re-evaluation of
Barrie Dale
doaj   +1 more source

New data on acritarchs from the Upper Ordovician of the Tungus basin, Siberian Platform [PDF]

open access: yesEstonian Journal of Earth Sciences, 2014
Distinctive late Ordovician acritarch assemblages have been discovered for the first time from about a 100 m sedimentary succession exposed along the Bol¢shaya Nirunda River in Siberia.
Elena Raevskaya, Andrei Dronov
doaj   +1 more source

Iso-Naakkima, a circular structure filled with Neoproterozoic sediments, Pieksämäki, southeastern Finland [PDF]

open access: yesBulletin of the Geological Society of Finland, 1993
A circular Bouguer gravity anomaly with a minimum of -4.0 mGal and half amplitude width of 2 km was recognized at Lake Iso-Naakkima (62°11'N, 27°09'E), southeastern Finland.
S. Elo   +4 more
doaj   +1 more source

Chronostratigrahy of Acritarchs and Chitinozoans from upper Ordovician Strata from the Robat-e Gharabil Area, NE Alborz Mountains, Northern Khorassan Province: Stratigraphic and Paleogeographic Implications [PDF]

open access: yesJournal of Sciences, Islamic Republic of Iran, 2018
The Palaeozoic rock units mainly, Ghelli, Niur, Padeha, Khoshyeilagh and Mobark formations are well-exposed in the north of Robat-e Gharabil village. 116 out of 157 surface samples were analyzed to determine aged relationships of Ghelli Formation.
M. Ghavidel-Syooki, S. Borji
doaj   +1 more source

Discovery of the messaoudensis–trifidum acritarch assemblage (upper Tremadocian–lower Floian, Lower Ordovician) in the subsurface of Morocco [PDF]

open access: yesEstonian Journal of Earth Sciences, 2015
The upper Tremadocian to lower Floian messaoudensis–trifidum acritarch assemblage was first described from the Skiddaw Group of England and subsequently from several localities on the Gondwanan margin that were positioned in high southern latitudes ...
Hendrik Nowak   +3 more
doaj   +1 more source

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