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A pan-Precambrian link between deglaciation and environmental oxidation

Open-File Report 2007-1047-KP-08

By:
and
DOI: 10.3133/ofr20071047KP08

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Abstract

Despite a continuous increase in solar luminosity to the present, Earth’s glacial record appears to become more frequent, though less severe, over geological time. At least two of the three major Precambrian glacial intervals were exceptionally intense, with solid evidence for widespread sea ice on or near the equator, well within a “Snowball Earth” zone produced by ice-albedo runaway in energy-balance models. The end of the first unambiguously low-latitude glaciation, the early Paleoproterozoic Makganyene event, is associated intimately with the first solid evidence for global oxygenation, including the world’s largest sedimentary manganese deposit. Subsequent low-latitude deglaciations during the Cryogenian interval of the Neoproterozoic Era are also associated with progressive oxidation, and these young Precambrian ice ages coincide with the time when basal animal phyla were diversifying. However, specifically testing hypotheses of cause and effect between Earth’s Neoproterozoic biosphere and glaciation is complicated because large and rapid True Polar Wander events appear to punctuate Neoproterozoic time and may have episodically dominated earlier and later intervals as well, rendering geographic reconstruction and age correlation challenging except for an exceptionally well-defined global paleomagnetic database.

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Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
A pan-Precambrian link between deglaciation and environmental oxidation
Series title:
Open-File Report
Series number:
2007-1047-KP-08
DOI:
10.3133/ofr20071047KP08
Year Published:
2007
Language:
English
Publisher:
National Academies Press
Publisher location:
Washington, DC
Description:
8 p.
Larger Work Type:
Report
Larger Work Subtype:
USGS Unnumbered Series
Larger Work Title:
Antarctica: A Keystone in a Changing World--Online Proceedings for the Tenth International Symposium on Antarctic Earth Sciences. Santa Barbara, California, U.S.A.--August 26 to September 1, 2007
First page:
83
Last page:
90