Origins and assessment of snowball Earth hypotheses

Harland, W. B. (2007) Origins and assessment of snowball Earth hypotheses. Geological Magazine, 144 (4). pp. 633-642. DOI 10.1017/S0016756807003391

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Abstract

Records of Precambrian glaciation onwards from the late nineteenth century led to the concept of one or more major ice ages. This concept was becoming well advanced by the mid 1930s, particularly through the compilation of Kulling in 1934. Even so tillite stratigraphy shows that glaciation was exceptional rather than typical of Earth history. Some Proterozoic tillites, sandwiched between warm marine facies, indicate low, even equatorial palaeolatitudes as determined magnetically, and more recently led to ideas of a snow- and ice-covered ‘snowball Earth’. However, interbedded non-glacial facies as well as thick tillite successions requiring abundant snowfall both militate against the hypothesis of extreme prolonged freezing temperatures referred to here as an ‘iceball Earth’ in which all oceans and seas were sealed in continuous ice cover. On the other hand tropical environments were interrupted by glaciation several times in the Proterozoic, something that did not recur in the Phanerozoic. The term ‘snowball Earth’ is consistent with the established view of extremely widespread Proterozoic glaciation, but the ‘iceball Earth’ version of this is not compatible with the geological record.

Item Type:	Article
Uncontrolled Keywords:	IA54 2007 P
Subjects:	01 - Climate Change and Earth-Ocean Atmosphere Systems 02 - Geodynamics, Geophysics and Tectonics
Divisions:	01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title:	Geological Magazine
Volume:	144
Page Range:	pp. 633-642
Identification Number:	10.1017/S0016756807003391
Depositing User:	Sarah Humbert
Date Deposited:	16 Feb 2009 13:02
Last Modified:	23 Jul 2013 10:07
URI:	http://eprints.esc.cam.ac.uk/id/eprint/348

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