Results 171 to 180 of about 25,970 (222)

Cambrian calcareous algae and bacteria

SPIE Proceedings, 2003
Individual calcareous algae were known in Riphean. Their mass distribution is connected to the beginning of Cambrian. Despite of a long history of study, the nature of this group long time remained not clear. The new unique finds of algae from East Sayan region have shown, that primary carbonate thallus disappeared in the process of fossilization, and ...
Veronica A. Luchinina, A. A. Terleev
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Palaeobiogeography of Ordovician calcareous algae

Palaeogeography, Palaeoclimatology, Palaeoecology, 1990
Abstract From the study of Ordivician algal microfloras the following can be concluded: during the Early Ordovician, the algal microflora is scantly, but cosmopolitan, and different from that of the Upper Cambrian. Its cosmopolitan character seems to denote the absence of a climatic gradient during that time.
J. Poncet, A. Roux
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Polysaccharides of Calcareous Algae and Their Effect on the Calcification Process

Russian Journal of Bioorganic Chemistry, 2001
The composition and structure of polysaccharides from several groups of calcareous algae (including calcareous cyanobacteria), which differ in the calcification mode (extracellular, cell wall, or intracellular), are reviewed. Two families of marine algae, Corallinaceae (Rhodophyta) and Cocolithophoraceae (Prymnesiophyta = Haptophyta), are considered in
M I, Bilan, A I, Usov
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The Permian Calcareous Alga Gymnocodium

Micropaleontology, 1955
On the basis of material from upper Permian limestone of northern Iraq erects a new family of red algae, Gymnocodiaceae, to include the genera Gymnocodium and Permocalculus n.g., and proposes two new species, P. digitus and P. plumosa.
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Paleogene calcareous algae from Egypt

Micropaleontology, 2002
Abstract Calcareous algae are common components in the shallow-marine limestones of the Drunka Formation (Early Eocene) cropping out on both banks of Nile between Sohag and Quena. Calcareous algae include: Acicularia valeti Segonzac, Sandalia pavsici Radoicic, Clypeina occidentalis (Johnson and Kaska), C. cf.
Ovidiu N. Dragastan, Hassan A. Soliman
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Carboniferous Calcareous Algae

1991
This compendium records 139 critically assessed valid genera and 22 form-genera of Carboniferous blue-green, green and red algae. It also includes some umbellinids, algal cysts and incertae sedis. For each genus, it lists the valid species and assesses suprageneric attributions. It records stratigraphic range, geographic distribution and abundance. The
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Cambrian Calcareous Cyanobacteria and Algae

1991
The Cambrian calcareous flora is dominated by cyanobacteria which include the Angulocellularia, Botomaella, Girvanella and Obruchevella groups. The important generic groups based on Renalcis and Epiphyton are also probably cyanobacterial. Proaulopora is possibly a cyanobacterium. No calcified red algae are known during the period.
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Receptaculitids are Calcareous Algae but no Dasyclads

1977
During the International Symposium on Fossil Algae at Erlangen, the receptaculitids were mentioned by several speakers. Riding, in his contribution on “Problems of afrmity in palaeozoic calcareous algae”, dealt with their nature, assuming that they might be sponges.
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Cambrian Calcareous Algae from Pennsylvania

American Midland Naturalist, 1937
These series contain four distinct forms of algal colonies, or deposits. The partly dolomitized specimens do not show whether the original material was finely clastic sediment entrapped by 'gelatinous coverings of the algae, or was precipitated because of algal life processes.t There also is no indication as to how many species may have cooperated in ...
Carroll Lane Fenton, Mildred Adams Fenton   +1 more
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Ordovician to Devonian Marine Calcareous Algae

1991
After the Cambrian, when calcified algae are rare or poorly known, the Ordovician-Devonian microfloras are largely dominated by chlorophytes, and particularly the filamentous (or nodular) codiaceans and the erect udoteaceans.
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