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Titel |
Precambrian glaciations and the evolution of the atmosphere |
VerfasserIn |
J. H. Carver, I. M. Vardavas |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
0992-7689
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Digitales Dokument |
URL |
Erschienen |
In: Annales Geophysicae ; 12, no. 7 ; Nr. 12, no. 7, S.674-682 |
Datensatznummer |
250010977
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Publikation (Nr.) |
copernicus.org/angeo-12-674-1994.pdf |
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Zusammenfassung |
Precambrian glaciations appear to be confined
to two periods, one in the early Proterozoic between 2.5 and 2 Gyears BP (Before
Present) and the other in the late Proterozoic between 1 and 0.57 Gyear BP.
Possible reasons for these broad features of the Precambrian climate have been
investigated using a simple model for the mean surface temperature of the Earth
that partially compensates for the evolution of the Sun by variations in the
atmospheric CO2 content caused by outgassing, the formation of
continents and the weathering of the Earth's land surface. It is shown that the
model can explain the main changes in the Precambrian climate if the early
Proterozoic glaciations were caused by a major episode of continental land
building commencing about 3 Gyears BP while the late Proterozoic glaciations
resulted from biologicallyenhanced weathering of the land surface due to the
proliferation of life forms in the transition from the Proterozoic to the
Phanerozoic that began about 1 Gyear BP. |
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