An interglacial on snowball Earth? Dynamic ice behaviour revealed in the Chuos Formation, Namibia
Abstract The Sturtian is the oldest ( ca 716 Ma) of three pan‐global glaciations in the Cryogenian. At Omutirapo, in northern Namibia, a 2 km wide, 400 m deep palaeovalley is filled by glaciogenic strata of the Chuos Formation, which represents the Sturtian glacial record. Sedimentary logging of an...
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crwiley:10.1111/j.1365-3091.2012.01346.x 2024-06-02T08:14:19+00:00 An interglacial on snowball Earth? Dynamic ice behaviour revealed in the Chuos Formation, Namibia LE HERON, DANIEL P. BUSFIELD, MARIE E. KAMONA, FRED 2012 http://dx.doi.org/10.1111/j.1365-3091.2012.01346.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-3091.2012.01346.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3091.2012.01346.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Sedimentology volume 60, issue 2, page 411-427 ISSN 0037-0746 1365-3091 journal-article 2012 crwiley https://doi.org/10.1111/j.1365-3091.2012.01346.x 2024-05-06T07:03:40Z Abstract The Sturtian is the oldest ( ca 716 Ma) of three pan‐global glaciations in the Cryogenian. At Omutirapo, in northern Namibia, a 2 km wide, 400 m deep palaeovalley is filled by glaciogenic strata of the Chuos Formation, which represents the Sturtian glacial record. Sedimentary logging of an exceptionally high‐quality exposure permits detailed stratigraphic descriptions and interpretations, allowing two glacial cycles to be identified. At the base of the exposed succession, strong evidence supporting glaciation includes diamictites, ice‐rafted dropstones and intensely sheared zones of interpreted subglacial origin. These facies collectively represent ice‐proximal to ice‐rafted deposits. Upsection, dropstone‐free mudstones in the middle of the succession, and the absence of diamictites, imply sedimentation free from glacial influence. However, the reappearance of glacial deposits above indicates a phase of Sturtian glacial re‐advance. Comparison with age‐equivalent strata in South Australia, where evidence for sea‐ice free sedimentation has been established previously, suggests that a Sturtian interglacial may have been extensive, implying global‐scale waxing and waning of ice sheets during a Cryogenian glacial event. Article in Journal/Newspaper Sea ice Wiley Online Library Sedimentology 60 2 411 427 |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract The Sturtian is the oldest ( ca 716 Ma) of three pan‐global glaciations in the Cryogenian. At Omutirapo, in northern Namibia, a 2 km wide, 400 m deep palaeovalley is filled by glaciogenic strata of the Chuos Formation, which represents the Sturtian glacial record. Sedimentary logging of an exceptionally high‐quality exposure permits detailed stratigraphic descriptions and interpretations, allowing two glacial cycles to be identified. At the base of the exposed succession, strong evidence supporting glaciation includes diamictites, ice‐rafted dropstones and intensely sheared zones of interpreted subglacial origin. These facies collectively represent ice‐proximal to ice‐rafted deposits. Upsection, dropstone‐free mudstones in the middle of the succession, and the absence of diamictites, imply sedimentation free from glacial influence. However, the reappearance of glacial deposits above indicates a phase of Sturtian glacial re‐advance. Comparison with age‐equivalent strata in South Australia, where evidence for sea‐ice free sedimentation has been established previously, suggests that a Sturtian interglacial may have been extensive, implying global‐scale waxing and waning of ice sheets during a Cryogenian glacial event. |
format |
Article in Journal/Newspaper |
author |
LE HERON, DANIEL P. BUSFIELD, MARIE E. KAMONA, FRED |
spellingShingle |
LE HERON, DANIEL P. BUSFIELD, MARIE E. KAMONA, FRED An interglacial on snowball Earth? Dynamic ice behaviour revealed in the Chuos Formation, Namibia |
author_facet |
LE HERON, DANIEL P. BUSFIELD, MARIE E. KAMONA, FRED |
author_sort |
LE HERON, DANIEL P. |
title |
An interglacial on snowball Earth? Dynamic ice behaviour revealed in the Chuos Formation, Namibia |
title_short |
An interglacial on snowball Earth? Dynamic ice behaviour revealed in the Chuos Formation, Namibia |
title_full |
An interglacial on snowball Earth? Dynamic ice behaviour revealed in the Chuos Formation, Namibia |
title_fullStr |
An interglacial on snowball Earth? Dynamic ice behaviour revealed in the Chuos Formation, Namibia |
title_full_unstemmed |
An interglacial on snowball Earth? Dynamic ice behaviour revealed in the Chuos Formation, Namibia |
title_sort |
interglacial on snowball earth? dynamic ice behaviour revealed in the chuos formation, namibia |
publisher |
Wiley |
publishDate |
2012 |
url |
http://dx.doi.org/10.1111/j.1365-3091.2012.01346.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-3091.2012.01346.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3091.2012.01346.x |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
Sedimentology volume 60, issue 2, page 411-427 ISSN 0037-0746 1365-3091 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1365-3091.2012.01346.x |
container_title |
Sedimentology |
container_volume |
60 |
container_issue |
2 |
container_start_page |
411 |
op_container_end_page |
427 |
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1800738119891288064 |