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Showing 1 to 15 of 15 for “"acritarchs"”.
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Constraining the Ediacaran-Cambrian boundary in South China using acanthomorphic acritarchs and Palaeopascichnus fossils
… criteria. Investigations of acanthomorphic acritarchs in basal Cambrian strata of South China suggest that these microfossils may provide an appropriate biostratigraphic marker for the Ediacaran-Cambrian boundary, because of their wide distribution in chert-phosphorite layers intercalated …
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Paleoceanography across the Pliocene–Pleistocene transition in the southern Bering Sea: dinoflagellate cysts and acritarchs from IODP Site U1341
… has been analyzed for dinoflagellate cysts, acritarchs and other palynomorphs. Based on 86 samples, with a spacing equivalent to between 500 and 6000 years, this is the most stratigraphically detailed late Cenozoic marine palynological study yet undertaken in the Bering Sea. The …
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Exceptional Preservation and Bias in the Fossil Record
… Formation in South China. Acanthomorphic acritarchs represent a promising tool for subdivision and correlation of the Doushantuo Formation of South China and Ediacaran strata around the world. However, the occurrence of acanthomorphic acritarchs within the Doushantuo Formation is …
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Integrated High-resolution Stratigraphy of the Doushantuo Formation, South China
… including the first appearance of large spiny acritarchs called the acanthomorphic acritarch, followed by the radiation of the Ediacara biota (575-542 Ma), and earliest recognizable bilaterally symmetrical animals (~550 Ma). It has been proposed that key environmental events, such as the …
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The palynology of selected Ordovician localities in Scotland
… of those genera. There are also five species of acritarchs in four genera as well as other microfossils. Black shales from the Complex yield the most diverse palynomorph assemblages, and were probably deposited from Arenig through to Caradoc although not necessarily at the same time in different …
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Applied Geochemistry, Geochronology and Biostratigraphy: Case Studies from the 38th Parallel Structures in Missouri and Orange Basin, Offshore Western South Africa
… in all the three structures. Early Ordovician acritarchs with melted processes correlate with <sup>40</sup>Ar-<sup>39</sup>Ar stepwise heating age of impact spherules from the Crooked Creek structure. This age is coeval with a large clustering event that was responsible for other craters in …
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Contributions to the Proterozoic and Cambrian Evolution of Eukaryotes
… cyanobacteria and eukaryotic phytoplankton (acritarchs). Careful investigation of the basal Cambrian Yanjiahe Formation in the Yangtze Gorges area and the Yurtus Formation in the Aksu area revealed abundant acanthomorphic acritarchs, clustered coccoidal microfossils, filamentous …
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Contributions and New Methods in Paleontology: Geochemical, Ultrastructural, and Microstructural Characterization of Archean, Proterozoic, and Phanerozoic Fossils
… investigation of organic-walled microfossils, or acritarchs, from the Paleoproterozoic (2500–1600 Ma) and Mesoproterozoic (1600–1000 Ma), using a range of advanced instrumentation including field emission scanning electron microscopy, transmission electron microscopy, laser Raman spectroscopy, …
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Organic-walled microplankton paleoecology and biostratigraphy of the Upper Cretaceous Ripley Formation, southwestern Georgia
… of chlorophytes, 3 genera and 4 species of acritarchs, and 1 problematical protozoan. 15 of these taxa are unpublished. The study's cyst assemblage was statistically analyzed to ascertain paleoecologic patterns. The results from cluster analysis and detrended correspondence analysis indicate …
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Entwicklung einer neuen Präparationsmethode und Untersuchung verkieselter Mikrofossilien des Präkambriums mit Hilfe der Rasterkraft- und Elektronenmikroskopie
… Territoriy, Australia, and 650 million year old acritarchs from the Chichkan Formation of Kasachstan. A classical analysis of size distributions within single populations of the microorganisms by light microscopy classified the cyanobacteria as Myxococcoides minor Schopf 1968, and the acritarchs …
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Detailed studies of the Callovian and Oxfordian microplankton from the Warboys and Warlingham boreholes
… the taxonomy of dinoflagellate cysts and acritarchs in terms of morphology and terminology. Chapter five constitutes the systematic part. From a total of 48 microplankton genera, some 120 dinoflagellate species and 18 acritarch species are described. 9 species are considered to be new and …
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Dinoflagellate cyst record and paleoceanography through the Pliocene–Pleistocene transition at ODP Site 1143, southern South China Sea
… Pool. This is the first study of dinocysts and acritarchs spanning the Pliocene–Pleistocene boundary in the South China Sea, and also appears to be the first record of Edwardsiella sexispinosa, Invertocysta tabulata and Operculodinium bahamense from the Pacific region.
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Maceral Variations and Maceral Assemblages within the Upper and Lower Members of the Bakken Formation, Williston Basin, Saskatchewan, Canada.
… or absence and type of microfossils (i.e. algae, acritarchs and spores) within each organic facies (and organic facies subdivision). The Bakken Formation black shales are interpreted to have been deposited under anoxic conditions, where changes in water chemistry and the availability of light were …
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A palynological investigation of Upper Jurassic basal Cretaceous sediments from England, France and Iberia
… assemblages (dinoflagellate cysts and acritarchs are recorded and described from the English and French sections which are well dated upon independent palaeontological evidence. The various taxa constituting the microplankton assemblages are - described and in part illustrated in a …
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Controls on the geometry, stratigraphic distribution and quality of coals of Middle to Upper Jurassic strata in eastern Australia
… the identification of tidally-influenced facies, acritarchs and dinoflagellate cysts (a first for Jurassic-aged strata in the basin) indicate periods of brackish water conditions. Marine incursions may have come from the north and the east during time of high eustatic sea-level during the …