Cryoplanation Terraces: Indicators of a Permafrost Environment
Cryoplanation terraces are bedrock steps or terraces on ridge crests and hilltops. The tread or “flat” area is 10 to several hundred meters wide and long and slopes from 1 to 5° parallel to the ridge crests. Terrace scarps may be from 1 to 75 m high. Terraces are cut into all bedrock types and are b...
Published in: | Quaternary Research |
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Language: | English |
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Cambridge University Press (CUP)
1976
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Online Access: | http://dx.doi.org/10.1016/0033-5894(76)90042-9 http://api.elsevier.com/content/article/PII:0033589476900429?httpAccept=text/xml http://api.elsevier.com/content/article/PII:0033589476900429?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400035109 |
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crcambridgeupr:10.1016/0033-5894(76)90042-9 2024-06-16T07:42:39+00:00 Cryoplanation Terraces: Indicators of a Permafrost Environment Reger, Richard D. Péwé, Troy L. 1976 http://dx.doi.org/10.1016/0033-5894(76)90042-9 http://api.elsevier.com/content/article/PII:0033589476900429?httpAccept=text/xml http://api.elsevier.com/content/article/PII:0033589476900429?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400035109 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Quaternary Research volume 6, issue 1, page 99-109 ISSN 0033-5894 1096-0287 journal-article 1976 crcambridgeupr https://doi.org/10.1016/0033-5894(76)90042-9 2024-05-22T12:56:33Z Cryoplanation terraces are bedrock steps or terraces on ridge crests and hilltops. The tread or “flat” area is 10 to several hundred meters wide and long and slopes from 1 to 5° parallel to the ridge crests. Terrace scarps may be from 1 to 75 m high. Terraces are cut into all bedrock types and are best developed on closely jointed, fine-grained bedrock. The scarps and treads are covered with frost-rived rubble 1 to 2 m thick. The rubble on treads is perennially frozen at a depth of 1 to 2 m or less on sharp but inactive terraces in Alaska. Cryoplanation terraces exist in many parts of the world in present or past periglacial environments. They occur chiefly in nonglaciated regions and near the general altitude of snowline. Cryoplanation terraces form by scarp retreat as the result of nivation. Surficial debris is removed across the terrace tread by mass-wasting. Terrace morphology depends mainly upon climate, bedrock type, and terrace orientation. No climatic data are available from active terraces. Indirect evidence indicates that climatic requirements include low snowfall and cold summer temperatures. Shallow permafrost is necessary to provide moisture and a base for mass movement as well as a base for nivation. Hundreds of sharp but inactive terraces occur in some areas in Alaska where the summer temperature is colder than 10°C. When these terraces were active, temperatures were colder. Recent work in Alaska indicates that terraces were active in some areas when the mean July temperature was about 4°C. The mean annual air temperature probably was in the neighborhood of -12°C or colder. Article in Journal/Newspaper permafrost Alaska Cambridge University Press Quaternary Research 6 1 99 109 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
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English |
description |
Cryoplanation terraces are bedrock steps or terraces on ridge crests and hilltops. The tread or “flat” area is 10 to several hundred meters wide and long and slopes from 1 to 5° parallel to the ridge crests. Terrace scarps may be from 1 to 75 m high. Terraces are cut into all bedrock types and are best developed on closely jointed, fine-grained bedrock. The scarps and treads are covered with frost-rived rubble 1 to 2 m thick. The rubble on treads is perennially frozen at a depth of 1 to 2 m or less on sharp but inactive terraces in Alaska. Cryoplanation terraces exist in many parts of the world in present or past periglacial environments. They occur chiefly in nonglaciated regions and near the general altitude of snowline. Cryoplanation terraces form by scarp retreat as the result of nivation. Surficial debris is removed across the terrace tread by mass-wasting. Terrace morphology depends mainly upon climate, bedrock type, and terrace orientation. No climatic data are available from active terraces. Indirect evidence indicates that climatic requirements include low snowfall and cold summer temperatures. Shallow permafrost is necessary to provide moisture and a base for mass movement as well as a base for nivation. Hundreds of sharp but inactive terraces occur in some areas in Alaska where the summer temperature is colder than 10°C. When these terraces were active, temperatures were colder. Recent work in Alaska indicates that terraces were active in some areas when the mean July temperature was about 4°C. The mean annual air temperature probably was in the neighborhood of -12°C or colder. |
format |
Article in Journal/Newspaper |
author |
Reger, Richard D. Péwé, Troy L. |
spellingShingle |
Reger, Richard D. Péwé, Troy L. Cryoplanation Terraces: Indicators of a Permafrost Environment |
author_facet |
Reger, Richard D. Péwé, Troy L. |
author_sort |
Reger, Richard D. |
title |
Cryoplanation Terraces: Indicators of a Permafrost Environment |
title_short |
Cryoplanation Terraces: Indicators of a Permafrost Environment |
title_full |
Cryoplanation Terraces: Indicators of a Permafrost Environment |
title_fullStr |
Cryoplanation Terraces: Indicators of a Permafrost Environment |
title_full_unstemmed |
Cryoplanation Terraces: Indicators of a Permafrost Environment |
title_sort |
cryoplanation terraces: indicators of a permafrost environment |
publisher |
Cambridge University Press (CUP) |
publishDate |
1976 |
url |
http://dx.doi.org/10.1016/0033-5894(76)90042-9 http://api.elsevier.com/content/article/PII:0033589476900429?httpAccept=text/xml http://api.elsevier.com/content/article/PII:0033589476900429?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400035109 |
genre |
permafrost Alaska |
genre_facet |
permafrost Alaska |
op_source |
Quaternary Research volume 6, issue 1, page 99-109 ISSN 0033-5894 1096-0287 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1016/0033-5894(76)90042-9 |
container_title |
Quaternary Research |
container_volume |
6 |
container_issue |
1 |
container_start_page |
99 |
op_container_end_page |
109 |
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1802010184870002688 |