Palynological and Radiocarbon Evidence for Deglaciation Events in the Green Bay Lobe, Wisconsin
A new and significant site of organic silty sand has been found beneath the Valders till at Valders Quarry in northeastern Wisconsin. This is now the earliest known late-glacial site associated with red till ice advances in the western Great Lakes area. Leaves of terrestrial plants washed into a sma...
Published in: | Quaternary Research |
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Cambridge University Press (CUP)
1996
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crcambridgeupr:10.1006/qres.1996.0064 2024-06-23T07:53:23+00:00 Palynological and Radiocarbon Evidence for Deglaciation Events in the Green Bay Lobe, Wisconsin Maher, Louis J. Mickelson, David M. 1996 http://dx.doi.org/10.1006/qres.1996.0064 http://api.elsevier.com/content/article/PII:S0033589496900642?httpAccept=text/xml http://api.elsevier.com/content/article/PII:S0033589496900642?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400039375 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Quaternary Research volume 46, issue 3, page 251-259 ISSN 0033-5894 1096-0287 journal-article 1996 crcambridgeupr https://doi.org/10.1006/qres.1996.0064 2024-05-29T08:10:04Z A new and significant site of organic silty sand has been found beneath the Valders till at Valders Quarry in northeastern Wisconsin. This is now the earliest known late-glacial site associated with red till ice advances in the western Great Lakes area. Leaves of terrestrial plants washed into a small depression provide a date of 12,965 ± 200 yr B.P. (WIS-2293), which is significantly older than the Two Creeks Forest Bed (ca. 11,800 yr B.P.). Percentage and concentration pollen diagrams suggest that the site was open and distant from a closed Picea forest. No wood or Picea needles have been found. This date is statistically indistinguishable from 12,550 ± 233 yr B.P., the mean of three dates for the end of inorganic varve sedimentation at Devils Lake, 160 km southwest at the terminus of the Green Bay Lobe. Assuming that the Green Bay lobe vacated its outermost moraine in the interval from 13,000 to 12,500 yr B.P., only a short time was available for retreat of the ice margin over 350 km, drainage of red sediment from Lake Superior into the Lake Michigan basin, readvance of over 250 km, retreat of at least 80 km, and advance to this site. The time for these events appears to have been too short to resolve by current radiocarbon technique. This extremely rapid collapse of the Green Bay lobe has a calibrated age of about 15,000 cal yr B.P., about that of the dramatic warming seen in the Greenland ice cores. Article in Journal/Newspaper Greenland Greenland ice cores Cambridge University Press Devils Lake ENVELOPE(-107.884,-107.884,56.717,56.717) Green Bay ENVELOPE(-36.014,-36.014,-54.870,-54.870) Greenland Valders ENVELOPE(15.406,15.406,67.303,67.303) Quaternary Research 46 3 251 259 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
A new and significant site of organic silty sand has been found beneath the Valders till at Valders Quarry in northeastern Wisconsin. This is now the earliest known late-glacial site associated with red till ice advances in the western Great Lakes area. Leaves of terrestrial plants washed into a small depression provide a date of 12,965 ± 200 yr B.P. (WIS-2293), which is significantly older than the Two Creeks Forest Bed (ca. 11,800 yr B.P.). Percentage and concentration pollen diagrams suggest that the site was open and distant from a closed Picea forest. No wood or Picea needles have been found. This date is statistically indistinguishable from 12,550 ± 233 yr B.P., the mean of three dates for the end of inorganic varve sedimentation at Devils Lake, 160 km southwest at the terminus of the Green Bay Lobe. Assuming that the Green Bay lobe vacated its outermost moraine in the interval from 13,000 to 12,500 yr B.P., only a short time was available for retreat of the ice margin over 350 km, drainage of red sediment from Lake Superior into the Lake Michigan basin, readvance of over 250 km, retreat of at least 80 km, and advance to this site. The time for these events appears to have been too short to resolve by current radiocarbon technique. This extremely rapid collapse of the Green Bay lobe has a calibrated age of about 15,000 cal yr B.P., about that of the dramatic warming seen in the Greenland ice cores. |
format |
Article in Journal/Newspaper |
author |
Maher, Louis J. Mickelson, David M. |
spellingShingle |
Maher, Louis J. Mickelson, David M. Palynological and Radiocarbon Evidence for Deglaciation Events in the Green Bay Lobe, Wisconsin |
author_facet |
Maher, Louis J. Mickelson, David M. |
author_sort |
Maher, Louis J. |
title |
Palynological and Radiocarbon Evidence for Deglaciation Events in the Green Bay Lobe, Wisconsin |
title_short |
Palynological and Radiocarbon Evidence for Deglaciation Events in the Green Bay Lobe, Wisconsin |
title_full |
Palynological and Radiocarbon Evidence for Deglaciation Events in the Green Bay Lobe, Wisconsin |
title_fullStr |
Palynological and Radiocarbon Evidence for Deglaciation Events in the Green Bay Lobe, Wisconsin |
title_full_unstemmed |
Palynological and Radiocarbon Evidence for Deglaciation Events in the Green Bay Lobe, Wisconsin |
title_sort |
palynological and radiocarbon evidence for deglaciation events in the green bay lobe, wisconsin |
publisher |
Cambridge University Press (CUP) |
publishDate |
1996 |
url |
http://dx.doi.org/10.1006/qres.1996.0064 http://api.elsevier.com/content/article/PII:S0033589496900642?httpAccept=text/xml http://api.elsevier.com/content/article/PII:S0033589496900642?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400039375 |
long_lat |
ENVELOPE(-107.884,-107.884,56.717,56.717) ENVELOPE(-36.014,-36.014,-54.870,-54.870) ENVELOPE(15.406,15.406,67.303,67.303) |
geographic |
Devils Lake Green Bay Greenland Valders |
geographic_facet |
Devils Lake Green Bay Greenland Valders |
genre |
Greenland Greenland ice cores |
genre_facet |
Greenland Greenland ice cores |
op_source |
Quaternary Research volume 46, issue 3, page 251-259 ISSN 0033-5894 1096-0287 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1006/qres.1996.0064 |
container_title |
Quaternary Research |
container_volume |
46 |
container_issue |
3 |
container_start_page |
251 |
op_container_end_page |
259 |
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1802644986324320256 |