Results 121 to 130 of about 2,601 (182)
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Proterozoic Atmospheric Oxygen
2014This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history of continental growth and volcanic outgassing, as well ...
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2020
The Banded Gneiss Complex attached to the Aravalli Craton in the west with coeval Bundelkhand Craton in the center, the Singhbhum and the Meghalaya Cratons in the east, and the Bastar and Dharwar cratons in the south constitute the Precambrian nuclei of the Peninsular India.
A. K. Jain +2 more
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The Banded Gneiss Complex attached to the Aravalli Craton in the west with coeval Bundelkhand Craton in the center, the Singhbhum and the Meghalaya Cratons in the east, and the Bastar and Dharwar cratons in the south constitute the Precambrian nuclei of the Peninsular India.
A. K. Jain +2 more
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Proterozoic Fossil Cyanobacteria
Journal of Palaeosciences, 2012A monographic account is presented on the fossil Proterozoic cyanobacteria. It chronicles the 60 years of history of investigations on the Precambrian microfossils. The researches on Precambrian microfossils have revealed a new, earlier unknown, world of oldest microorganisms and divulged the steps in life’s evolution on the earth.
V. N. Sergeev +2 more
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1982
The Dominion Group, Witwatersrand Supergroup, and Ventersdorp Supergroup constitute a volcanosedimentary sequence that is famous for its fossil gold placers. It has been estimated that since gold-bearing conglomerates were discovered near Johannesburg (Fig. 4-1) in 1886, mines in the Transvaal and Orange Free State have produced more than 55 percent of
A. J. Tankard +5 more
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The Dominion Group, Witwatersrand Supergroup, and Ventersdorp Supergroup constitute a volcanosedimentary sequence that is famous for its fossil gold placers. It has been estimated that since gold-bearing conglomerates were discovered near Johannesburg (Fig. 4-1) in 1886, mines in the Transvaal and Orange Free State have produced more than 55 percent of
A. J. Tankard +5 more
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Proterozoic stromatolite zonation
American Journal of Science, 1969The zonation of the Proterozoic of the USSR is reviewed and extension to other places is attempted. Preliminary results are: some of the columnar stromatolites of northern Eurasia occur in other continents and in the same stratigraphic ranges; some of the forms (9species9) of the distinctive columnar types have intercontinental distribution, such as ...
P. E. Cloud, M. A. Semikhatov
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Paleobiology, 2005
Abstract A large, morphologically heterogeneous population of acanthomorphic acritarchs from the early Neoproterozoic Wynniatt Formation, Victoria Island, northwestern Canada, is ascribed to two form-genera, Tappania and Germinosphaera, but just a single natural taxon, Tappania. Analysis of Tappania morphology shows it to have been an actively growing,
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Abstract A large, morphologically heterogeneous population of acanthomorphic acritarchs from the early Neoproterozoic Wynniatt Formation, Victoria Island, northwestern Canada, is ascribed to two form-genera, Tappania and Germinosphaera, but just a single natural taxon, Tappania. Analysis of Tappania morphology shows it to have been an actively growing,
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2020
The Indian Subcontinent is comprised of the Archean-Proterozoic cratons, the Aravalli Craton, the Bundelkhand Craton, the Mehghalaya Craton, the Bastar Craton, the Singhbhum Craton and the Dharwar Craton.
A. K. Jain +2 more
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The Indian Subcontinent is comprised of the Archean-Proterozoic cratons, the Aravalli Craton, the Bundelkhand Craton, the Mehghalaya Craton, the Bastar Craton, the Singhbhum Craton and the Dharwar Craton.
A. K. Jain +2 more
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Proterozoic Anorthosite Massifs
1985Major anorthositic massifs intruded stable cratonic crust in the North Atlantic region about 1.4 to 1.7 Ga ago. Similar (meta-) anorthosite massifs (0.9–1.6 Ga) in Grenville and Sveconorwegian terranes exhibit varying degrees of deformational and metamorphic overprint and consequently have ambiguous tectonic settings.
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