Time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat
Abstract Cryoplanation terraces are elevated bedrock features resembling giant staircases, with alternating steep scarps and shallow sloping treads. These landscape‐scale features have long been associated with periglacial environments, but the processes involved in their formation remain vaguely sp...
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crwiley:10.1002/esp.4751 2024-10-13T14:11:21+00:00 Time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat Nyland, Kelsey E. Nelson, Frederick E. Michigan State University 2020 http://dx.doi.org/10.1002/esp.4751 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fesp.4751 https://onlinelibrary.wiley.com/doi/pdf/10.1002/esp.4751 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/esp.4751 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Earth Surface Processes and Landforms volume 45, issue 3, page 526-534 ISSN 0197-9337 1096-9837 journal-article 2020 crwiley https://doi.org/10.1002/esp.4751 2024-09-17T04:47:41Z Abstract Cryoplanation terraces are elevated bedrock features resembling giant staircases, with alternating steep scarps and shallow sloping treads. These landscape‐scale features have long been associated with periglacial environments, but the processes involved in their formation remain vaguely specified and contentious. The two leading hypotheses for the formation of cryoplanation terraces are centered on: (1) geologic structure; and (2) nivation‐driven scarp retreat. The nivation‐formation hypothesis invokes scarp retreat under erosion processes associated with late‐lying snowbanks. To test whether cryoplanation terraces develop through scarp retreat, six relative weathering indices (fracture counts, Cailleux roundness, Cailleux flatness, Krumbein sphericity, rebound, and weathering rind thickness) were measured across well‐developed terraces in unglaciated eastern Beringia (central and western Alaska) at Mt Fairplay, Eagle Summit, and Skookum Pass. Statistically significant differences in relative weathering indices detected through chi‐square and multiple‐comparison procedures indicate that material is less weathered closer to scarps, i.e. that these areas were more recently exposed than those distant from the scarp. Based on these findings, a refined model of time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat is proposed. This new qualitative model addresses the removal of weathered material from terrace treads down side slopes through piping and gravity‐driven mass‐wasting processes. © 2019 John Wiley & Sons, Ltd. Article in Journal/Newspaper Alaska Beringia Wiley Online Library Earth Surface Processes and Landforms 45 3 526 534 |
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Wiley Online Library |
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crwiley |
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English |
description |
Abstract Cryoplanation terraces are elevated bedrock features resembling giant staircases, with alternating steep scarps and shallow sloping treads. These landscape‐scale features have long been associated with periglacial environments, but the processes involved in their formation remain vaguely specified and contentious. The two leading hypotheses for the formation of cryoplanation terraces are centered on: (1) geologic structure; and (2) nivation‐driven scarp retreat. The nivation‐formation hypothesis invokes scarp retreat under erosion processes associated with late‐lying snowbanks. To test whether cryoplanation terraces develop through scarp retreat, six relative weathering indices (fracture counts, Cailleux roundness, Cailleux flatness, Krumbein sphericity, rebound, and weathering rind thickness) were measured across well‐developed terraces in unglaciated eastern Beringia (central and western Alaska) at Mt Fairplay, Eagle Summit, and Skookum Pass. Statistically significant differences in relative weathering indices detected through chi‐square and multiple‐comparison procedures indicate that material is less weathered closer to scarps, i.e. that these areas were more recently exposed than those distant from the scarp. Based on these findings, a refined model of time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat is proposed. This new qualitative model addresses the removal of weathered material from terrace treads down side slopes through piping and gravity‐driven mass‐wasting processes. © 2019 John Wiley & Sons, Ltd. |
author2 |
Michigan State University |
format |
Article in Journal/Newspaper |
author |
Nyland, Kelsey E. Nelson, Frederick E. |
spellingShingle |
Nyland, Kelsey E. Nelson, Frederick E. Time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat |
author_facet |
Nyland, Kelsey E. Nelson, Frederick E. |
author_sort |
Nyland, Kelsey E. |
title |
Time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat |
title_short |
Time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat |
title_full |
Time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat |
title_fullStr |
Time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat |
title_full_unstemmed |
Time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat |
title_sort |
time‐transgressive cryoplanation terrace development through nivation‐driven scarp retreat |
publisher |
Wiley |
publishDate |
2020 |
url |
http://dx.doi.org/10.1002/esp.4751 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fesp.4751 https://onlinelibrary.wiley.com/doi/pdf/10.1002/esp.4751 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/esp.4751 |
genre |
Alaska Beringia |
genre_facet |
Alaska Beringia |
op_source |
Earth Surface Processes and Landforms volume 45, issue 3, page 526-534 ISSN 0197-9337 1096-9837 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/esp.4751 |
container_title |
Earth Surface Processes and Landforms |
container_volume |
45 |
container_issue |
3 |
container_start_page |
526 |
op_container_end_page |
534 |
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1812819075387097088 |