Results 191 to 200 of about 61,505 (248)
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1982
Abstract Phanerozoic tectonics have not affected the basic integrity of the North American continent. From time to time, sialic crustal elements have been rifted off, accreted onto, and slipped along the continent’s margins, but the vast continental interior has remained intact.
P. F. Hoffman, K. D. Card, A. Davidson
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Abstract Phanerozoic tectonics have not affected the basic integrity of the North American continent. From time to time, sialic crustal elements have been rifted off, accreted onto, and slipped along the continent’s margins, but the vast continental interior has remained intact.
P. F. Hoffman, K. D. Card, A. Davidson
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Life on Land in the Precambrian
Science, 1994Microfossils have been discovered in cavity-fill and replacement silica that occurs between chert-breccia clasts in 1200-million-year-old paleokarst at the top of the Mescal Limestone, central Arizona, and in ∼800-million-year-old paleokarst at the top of the Beck Spring Dolomite, southeastern California.
R J, Horodyski, L P, Knauth
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Precambrian Research, 1986
Abstract The Subcommission on Precambrian Stratigraphy, consisting at the time of its last formal meeting in 1982 of 12 titular Members and 30 Correspondents, has been actively working toward an acceptable subdivision of Precambrian time for more than a decade.
Kenneth A. Plumb, Harold L. James
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Abstract The Subcommission on Precambrian Stratigraphy, consisting at the time of its last formal meeting in 1982 of 12 titular Members and 30 Correspondents, has been actively working toward an acceptable subdivision of Precambrian time for more than a decade.
Kenneth A. Plumb, Harold L. James
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Subdivision of the Precambrian
Geological Society, London, Memoirs, 1985Abstract The Precambrian record is so fragmentary and from such widely contrasting terrains that attempts to erect any formal subdivisions would appear to be premature. The methods that have been used in the Phanerozoic rocks cannot be used for subdividing the Precambrian as they are peculiarly suitable for fossiliferous largely undeformed ...
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Nature, 1963
IN his recent book on The Geological Aspects of the Origin of Life on Earth, Prof. M. G. Rutten has adopted as his central thesis the postulate that the Earth retained its primaeval reducing atmosphere up to 1,500–2,000 million years ago. This conclusion is based on the premise that the gold–uranium ores of the Witwatersrand (South Africa), Blind River
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IN his recent book on The Geological Aspects of the Origin of Life on Earth, Prof. M. G. Rutten has adopted as his central thesis the postulate that the Earth retained its primaeval reducing atmosphere up to 1,500–2,000 million years ago. This conclusion is based on the premise that the gold–uranium ores of the Witwatersrand (South Africa), Blind River
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Geological Magazine, 1976
SummaryThe history of investigation of the rocks at present classed as Precambrian in the type region of the Cambrian system in the north-west corner of wales (Cambria), where that system was first named and its lower limit locally defined, is reviewed.
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SummaryThe history of investigation of the rocks at present classed as Precambrian in the type region of the Cambrian system in the north-west corner of wales (Cambria), where that system was first named and its lower limit locally defined, is reviewed.
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1988
As we have seen in the previous chapter, it becomes progressively more difficult to interpret the structure of orogenic belts as we look further back in time, beyond the period when accurate continental reconstructions can be made from oceanic palaeomagnetic data.
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As we have seen in the previous chapter, it becomes progressively more difficult to interpret the structure of orogenic belts as we look further back in time, beyond the period when accurate continental reconstructions can be made from oceanic palaeomagnetic data.
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