Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA
ABSTRACT A pre‐Late Wisconsinan, post‐Illinoian, till sheet has long been recognized in north‐central Iowa, but has not been formally recognized or defined until now. Early researchers referred to these deposits as the ‘Tazewell’, and the term ‘Sheldon Creek’ was more recently used informally by the...
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crwiley:10.1002/jqs.3627 2024-09-15T18:12:17+00:00 Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA Tassier‐Surine, STEPHANIE A. Kerr, PHILLIP J. Kilgore, SUSAN M. Cramer, BRADLEY D. U.S. Geological Survey 2024 http://dx.doi.org/10.1002/jqs.3627 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.3627 en eng Wiley http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ Journal of Quaternary Science volume 39, issue 6, page 905-918 ISSN 0267-8179 1099-1417 journal-article 2024 crwiley https://doi.org/10.1002/jqs.3627 2024-08-13T04:13:39Z ABSTRACT A pre‐Late Wisconsinan, post‐Illinoian, till sheet has long been recognized in north‐central Iowa, but has not been formally recognized or defined until now. Early researchers referred to these deposits as the ‘Tazewell’, and the term ‘Sheldon Creek’ was more recently used informally by the Iowa Geological Survey in guidebooks and reports. Recent mapping has extended the eastern margin significantly past previous interpretations. The Sheldon Creek Formation has similar lithologic characteristics to the overlying Alden Member of the Dows Formation, and the two units are distinguished mainly by stratigraphic position. Differentiation from underlying Pre‐Illinoian till units is accomplished using lithology, primarily matrix grain‐size and sand fraction lithology. A suite of 22 radiocarbon ages indicate two distinct, separate groupings within the Sheldon Creek data. These data strongly suggest ice advanced south to 42° N twice, once during Marine Isotope Stage (MIS) 3 and again during late MIS 3 or possibly early MIS 2. The presence of the Laurentide Ice Sheet in northern Iowa during MIS 3 has significant implications for ice sheet reconstructions during this interval. Article in Journal/Newspaper Ice Sheet Wiley Online Library Journal of Quaternary Science |
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Open Polar |
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Wiley Online Library |
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language |
English |
description |
ABSTRACT A pre‐Late Wisconsinan, post‐Illinoian, till sheet has long been recognized in north‐central Iowa, but has not been formally recognized or defined until now. Early researchers referred to these deposits as the ‘Tazewell’, and the term ‘Sheldon Creek’ was more recently used informally by the Iowa Geological Survey in guidebooks and reports. Recent mapping has extended the eastern margin significantly past previous interpretations. The Sheldon Creek Formation has similar lithologic characteristics to the overlying Alden Member of the Dows Formation, and the two units are distinguished mainly by stratigraphic position. Differentiation from underlying Pre‐Illinoian till units is accomplished using lithology, primarily matrix grain‐size and sand fraction lithology. A suite of 22 radiocarbon ages indicate two distinct, separate groupings within the Sheldon Creek data. These data strongly suggest ice advanced south to 42° N twice, once during Marine Isotope Stage (MIS) 3 and again during late MIS 3 or possibly early MIS 2. The presence of the Laurentide Ice Sheet in northern Iowa during MIS 3 has significant implications for ice sheet reconstructions during this interval. |
author2 |
U.S. Geological Survey |
format |
Article in Journal/Newspaper |
author |
Tassier‐Surine, STEPHANIE A. Kerr, PHILLIP J. Kilgore, SUSAN M. Cramer, BRADLEY D. |
spellingShingle |
Tassier‐Surine, STEPHANIE A. Kerr, PHILLIP J. Kilgore, SUSAN M. Cramer, BRADLEY D. Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA |
author_facet |
Tassier‐Surine, STEPHANIE A. Kerr, PHILLIP J. Kilgore, SUSAN M. Cramer, BRADLEY D. |
author_sort |
Tassier‐Surine, STEPHANIE A. |
title |
Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA |
title_short |
Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA |
title_full |
Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA |
title_fullStr |
Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA |
title_full_unstemmed |
Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA |
title_sort |
defining the sheldon creek formation, a middle wisconsinan (mis 3) till in iowa, usa |
publisher |
Wiley |
publishDate |
2024 |
url |
http://dx.doi.org/10.1002/jqs.3627 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.3627 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Journal of Quaternary Science volume 39, issue 6, page 905-918 ISSN 0267-8179 1099-1417 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1002/jqs.3627 |
container_title |
Journal of Quaternary Science |
_version_ |
1810449872668590080 |