1 edition of Algal stromatolites of the Early Proterozoic Wolkberg Group, Transvaal Sequence found in the catalog.
Algal stromatolites of the Early Proterozoic Wolkberg Group, Transvaal Sequence
|The Physical Object|
Multicellular algae are included in this group and finally the first animals appeared at the end period of the Proterozoic Era. Division of the Proterozoic Era This era is divided into 4 major periods and each of these periods had special features which contributed to understand the Proterozoic Era. This Early Proterozoic sequence is formally termed the Willyama Supergroup. The supergroup can be extended to sequences in the Early‐Middle Proterozoic metamorphic complexes of the Euriowie, Olary and Mount Painter Blocks, and can be broadly compared with Early Proterozoic sequences in .
The zoning scheme is extended to the early Proterozoic and three distinctive stromatolites are identified from the Mount Bruce Supergroup (approximately m.y. old). These are different from younger stromatolites but one also occurs in the early Proterozoic Ventersdorp 'System' of . The need to erect new groups for these early Proterozoic stromatolites is in agreement with recent studies in Canada, northern Europe and South Africa, and suggests that the problem of 'younger' or late Proterozoic stromatolite groups in early Proterozoic rocks mentioned by previous workers is a result of a lack of rigour in defining taxa.
An early origin of phototrophy is consistent with the earliest bacterial mats and structures identified as stromatolites, but a 2, Ma origin of cyanobacteria sug-. In the following pages, we evaluate the rapidly accumulating data on oxygen and biological evolution during two intervals often inferred to have been critical junctures in the history of life: (1) early in the Proterozoic Eon (ca. Ma), when increases in PO 2 above the Pasteur point are thought to have made possible the evolution of aerobic.
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Button, A.: Early proterozoic algal stromatolites of the Pretoria Group, Transvaal Sequence. Trans. Geol. Soc. Afr – ().
Google ScholarCited by: 1. Chemistry and morphology of Precambrian microorganisms. Nature, Button, A., Early Proterozoic algal stromatolites of the Pretoria Group, Transvaal Sequence. Button, A., Algal stromatolites from the early Proterozoic Wolkberg Group, Transvaal Sequence.
ButtonAlgal stromatolites from the early Proterozoic Author: K.A. Eriksson, I.M. MacGregor. The Wolkberg Group (sensu strfcto, SACS, } is thickest in the Selati trough of the northeastern Transvaal, where the Sadowa Formation is over- lain by a "main quartzite sequence" and the suc- ceeding 'The Downs sequence" (Fig.
3), both in- formal stratigraphlc units not yet recognised by SACS (Schwellnus et aL, ; Clendenin et al., ).Cited by: The Proterozoic Malmani Subgroup in the Chuniespoort Group (±2,4 Ga), of the Transvaal Supergroup, hosts five formations of dolomitic rocks, namely the Oaktree (oldest), Monte Christo.
Journal of African Earth Sciences, Vol. 13, No. 1, pp./91 $ + Printed in Thailand Pergamon Press plc A review of the sedimentology of the Early Proterozoic Pretoria Group, Transvaal Sequence, South Africa: implications for tectonic setting P.
N, U. SCHREmER and M. VAN DER NEUT Department of Geology, University of Cited by: Stromatolites were common in Precambrian time (i.e., more than million years ago).
Some of the first forms Transvaal Sequence book life on Earth are recorded in stromatolites present in rocks billion years old.
Although stromatolites continue to form in certain areas of the world today, they grow in greatest abundance in Shark Bay in western Australia.A matlike layer of blue-green algae is able to grow on. Algal stromatolites of the early Proterozoic Wolkberg Group, Transvaal Sequence.
Andrew Button. Abstract. View article. PDF. Moon Rocks and Minerals (book review) John F. Lindsay. View article. Add to Citation Manager. Journal of Sedimentary Research Ma The stromatolites are considered to be the accretionary product of algal mats growing in shallow water (Hoff- man, ; Park, ).
Those developing in basin margin locations were subjected to conditions of frequent subaerial exposure and moderate wave agitation resulting in the development of desiccation and fenestral structures.
Fossil microorganisms from the approximately to million-year-old Bulawayan stromatolite: Application of ultramicrochemical analyses of bacteria and blue-green algae, have been found. The Depositional History of the Wolkberg Proto-Basin, Transvaal. July,18pp.
Lenthall. The Application of Discriminatory and Cluster Analysis as and Aid to the Understanding of the Acid Phase of the Bushveld Complex. October,33pp.
Button. The Stratigraphic History of the Malmani Dolomite in the Eastern and. Button, A. Algal stromatolites of the early Proterozoic Wolkberg Group, Transvaal Sequence. Jour. Sed. Petrol., – Google Scholar. Siliceous algal and bacterial stromatolites in hot spring and geyser effluents of Yellowstone National Park.
Science, – eBook Packages Springer Book Archive; Buy this book on. Beukes, N. J., Facies relations, depositional environments and diagenesis in a major early Proterozoic stromatolitic carbonate platform to basinal sequence, Campbellrand Subgroup, Transvaal Supergroup, Southern Africa.
Sedimentary Geology, 54, 1– CrossRef Google Scholar. Grey K () Biostratigraphic studies of stromatolites from the Proterozoic Earaheedy Group, Nabbera Basin, Western Australia. Bull Geol Sury W Austzal Google Scholar Grey K () Stromatolites and other organic remains in the Bangemall Basin.
Millimeter to meter scale edifices (stromatolites) are the result. Stromatolites once played a significant role in establishing life's presence on the early Earth, but now a shift away from reliance on stromatolites is occurring.
There is a perception that Archean stromatolite-like structures have low reliability to signal life. The first traces of life appear nearly billion years ago, in the early Archean.
However, clearly identifiable fossils remain rare until the late Archean, when stromatolites, layered mounds produced by the growth of microbial mats, become common in the rock record. Stromatolite diversity increased through most of the Proterozoic.
The – Ga Mendon Formation, Onverwacht Group. Byerly et al. () described stromatolite-like features from three locations in what is now identified as the Ga M2c horizon of the Mendon Formation of the Onverwacht Group (Decker et al., ; Lowe and Byerly, ).
Proterozoic stromatolites: The first marine evolutionary biota Stanley M. Awramik Department of Geological Sciences, Preston Cloud Research Laboratory, University of California, Santa Barbara, California, E-mail: [email protected] & James Sprinkle Department of Geological Sciences, University of Texas, Austin, Texas, Stromatolites are critical geological features as they are the only biogenic sedimentary structures that have an age range extending fully from the early Archean to the Recent, thereby demonstrating a fundamentally uniformitarian phenomenon.
Columnar stromatolites representing more than a half of species described in Precambrian stromatolite assemblages reveal a regular trend of size variations during the Proterozoic and Early Paleozoic. The period of Earth's history that began billion years ago and ended million years ago is known as the Proterozoic.
Many of the most exciting events in the history of the Earth and of life occurred during the Proterozoic -- stable continents first appeared and began to accrete, a long process taking about a billion years.
Proterozoic Era: Life. The first traces of life appear nearly billion years ago, in the early Archaean. However, clearly identifiable fossils remain rare until the late Archaean, when stromatolites, layered mounds produced by the growth of microbial mats, become common in the rock tolite diversity continued to increase through most of the Proterozoic.The stromatolite-bearing interval in the lower Missoula Group was deposited in a shallow, intermittently exposed setting of very low relief, the stromatolites forming during periods of submergence.Abstract.
Five instances of association between distinctive stromatolites and blue-green algal nannofossils are recorded from a m sequence of carbonate rocks about × 10 9 years old, along the south side of Paradise Creek, northwestern Queensland, Australia.
No eukaryotes were identified in any of these systematically limited assemblages, although they are known from rocks as old as 1.