Results 151 to 160 of about 1,147 (200)
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Silurian acritarchs: distribution and trends
Review of Palaeobotany and Palynology, 1974Abstract Using as point of departure data from hundreds of localities with, essentially, Middle Silurian acritarch assemblages, logical constraints on the composition of these assemblages as they can be inferred from geological information, are discussed.
Fritz H. Cramer +1 more
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Neoproterozoic Acritarch Biostratigraphy of China
2020According to studies of the acritarch biostratigraphy in China, the evolution of Neoproterozoic acritarchs roughly involves four stages, from older to younger, including the pre-Doushantuo Stage, the Doushantuo Stage, the Denying Stage and the Meishucun Stage.
Yin Leiming, Yin Chongyu
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Review of Palaeobotany and Palynology, 1967
Abstract Globular organisms which are found in great abundance in the Posidonia shales of northwestern Germany, have been added to the hystrichosphaerids by Eisenack (1954, 1958), who also included the Tasmanites forms from older formations in this group.
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Abstract Globular organisms which are found in great abundance in the Posidonia shales of northwestern Germany, have been added to the hystrichosphaerids by Eisenack (1954, 1958), who also included the Tasmanites forms from older formations in this group.
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Acritarchs in carbonaceous meteorites and terrestrial rocks
SPIE Proceedings, 2013Acritarchs are a group of organic-walled, acid-resistant microfossils of uncertain or unknown origin. Some are thought to represent the cysts or resting stages of unicellular protists (possibly dinoflagellates), chrysophytes (green algae) or other planktonic eukaryotic algae.
Alexei Y. Rozanov, Richard B. Hoover
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Some considerations on acritarch classification
Review of Palaeobotany and Palynology, 1996Abstract Acritarchs are an important group in palynology and especially relevant in lower Palaeozoic sediments. Some 30 years after the group Acritarcha was defined and their systematics examined, their classification should again be debated amongst a wider group of workers.
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Biogeography of upper Llandovery and Wenlock acritarchs
Review of Palaeobotany and Palynology, 1995Abstract The world-wide spatial distribution of upper Llandovery and Wenlock acritarch microfloras is assessed using qualitative data, similarity indexes and cluster analysis. The database consists of comprehensive lists of taxa available essentially from eastern North America, South America, western Europe, Baltoscandia, Siberia, North Africa and ...
Alain Le Hérissé, Rémy Gourvennec
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Chapter 9.1 Neoproterozoic Acritarch Evolution
2009Acritarchs are key for unravelling Neoproterozoic biodiversity changes because they represent the only fossil group occurring throughout the era. Their Neoproterozoic evolution is characterised by drastic diversity changes, which, coupled to the occurrence of taxa with restricted stratigraphic range, represents a powerful biostratigraphic tool for the ...
Claudio Gaucher, Peter Sprechmann
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The Ordovician acritarch Frankea:Some critical remarks
Geobios, 1997Abstract The taxonomy of the acritarch genus Frankea Burmann , 1970 is clarified. Five species belong to thegenus: breviuscula, hamata, hamulata, longiuscula and sartbernardensis . Intraspecific variability is great, and it is difficult to distinguish the species sartbernardensis, breviuscula and longiuscula , which show a gradual increase
Oldrich Fatka +2 more
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Clypeolus, A new acritarch genus from the Ordovician and Silurian
Review of Palaeobotany and Palynology, 1997Clypeolus Miller, Playford et Le Hérissé, gen. nov. is established as a new acritarch genus based on C. tortugaides (Cramer) Miller, Playford et Le Hérissé, comb. nov. et emend. as the type species. The genus incorporates distinctly muronate vesicles that are shield-like or hemispherical and open equatorially, possibly resulting from an undetermined ...
Miller, Merrell A. +2 more
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Lower Cambrian acritarch stratigraphy in Scandinavia
Geologiska Föreningen i Stockholm Förhandlingar, 1981Acritarchs are reported from units of the basal Cambrian sequences in Denmark (Bornholm), southern Sweden (Scania and Vastergotland), and southern Norway (Lake Mjosa area).
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