Development of thermokarst lakes during the holocene at sites near Mayo, Yukon territory
The origin and growth of numerous thermokarst lakes near Mayo, central Yukon, has been examined, using ground surveys, aerial photographs and dendrochronology. Many of the lakes are currently expanding, at rates of axial increment up to 1.2 m/yr. Three lakes, whose axes are currently enlarging at ab...
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Online Access: | https://doi.org/10.1002/ppp.3430010207 |
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ftrepec:oai:RePEc:wly:perpro:v:1:y:1990:i:2:p:161-175 2023-05-15T17:10:30+02:00 Development of thermokarst lakes during the holocene at sites near Mayo, Yukon territory C. R. Burn M. W. Smith https://doi.org/10.1002/ppp.3430010207 unknown https://doi.org/10.1002/ppp.3430010207 article ftrepec https://doi.org/10.1002/ppp.3430010207 2020-12-04T13:31:03Z The origin and growth of numerous thermokarst lakes near Mayo, central Yukon, has been examined, using ground surveys, aerial photographs and dendrochronology. Many of the lakes are currently expanding, at rates of axial increment up to 1.2 m/yr. Three lakes, whose axes are currently enlarging at about 1.0 m/yr, were studied in particular detail: tree‐ring analysis indicates that these lakes formed by the middle to the late part of the last century. The talik profile was determined beneath one lake, and is consistent with the Stefan solution for thawing of ice‐rich soil with such an initiation date and rate of expansion. Organic‐rich horizons containing logs, vegetative detritus and fresh‐water ostracods have been exposed in two retrogressive thaw slumps near the lakes. These horizons have been interpreted as the bottoms of former thermokarst lakes. Radiocarbon dates of approximately 8500 BP, 3900 BP and 2300 BP have been obtained, indicating several periods of thermokarst activity during the Holocene. The results suggest that thermokarst lake development is not solely associated with changing climatic conditions in this region, since the current lakes and those that formed around 2300 BP do not appear to be directly linked to climatic warming. It is suggested that the most recent initiation of thermokarst activity is related to the effects of forest fires. L'origine et la croissance de nombreux lacs thermokarstiques prés de Mayo dans le Centre du Yukon ont été examinés en utilisant des observations au sol, des photographies aériennes et la dendrochronologie. Beaucoup de lacs sont en expansion, avec des vitesses d'allongement axial dépassant 1,2 m par an. Trois lacs dont les axes augmentent couramment d'environ 1 mètre par an, ont été étudiés avec un détail particulier: les analyses dendrochronologiques indiquent que ces lacs se sont formés au milieu de la deuxième partie du dernier siècle. Le profil du talik a été déterminé sous un lac, et est en accord avec la solution de Stefan pour le dégel d'un sol riche en glace avec la date de départ proposée et la vitesse d'expansion mesurée. Des horizons riches en matières organiques contenant des troncs d'arbres, des détritus végétaux et des ostracodes d'eau douce ont été mis à jour par deux slumps rétrogressifs de dégel à proximité des lacs. Ces horizons ont été interprétés comme des fonds de lacs de thermokarst antérieurs. Des dates 14C de plus ou moins 8500, 3900 et 2300 ans BP ont été obtenues indiquant plusieurs périodes d'activité failed to indicate any individuals that were more than 200 years old. Article in Journal/Newspaper Mayo Thermokarst Yukon RePEc (Research Papers in Economics) Talik ENVELOPE(146.601,146.601,59.667,59.667) Yukon Permafrost and Periglacial Processes 1 2 161 175 |
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Open Polar |
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RePEc (Research Papers in Economics) |
op_collection_id |
ftrepec |
language |
unknown |
description |
The origin and growth of numerous thermokarst lakes near Mayo, central Yukon, has been examined, using ground surveys, aerial photographs and dendrochronology. Many of the lakes are currently expanding, at rates of axial increment up to 1.2 m/yr. Three lakes, whose axes are currently enlarging at about 1.0 m/yr, were studied in particular detail: tree‐ring analysis indicates that these lakes formed by the middle to the late part of the last century. The talik profile was determined beneath one lake, and is consistent with the Stefan solution for thawing of ice‐rich soil with such an initiation date and rate of expansion. Organic‐rich horizons containing logs, vegetative detritus and fresh‐water ostracods have been exposed in two retrogressive thaw slumps near the lakes. These horizons have been interpreted as the bottoms of former thermokarst lakes. Radiocarbon dates of approximately 8500 BP, 3900 BP and 2300 BP have been obtained, indicating several periods of thermokarst activity during the Holocene. The results suggest that thermokarst lake development is not solely associated with changing climatic conditions in this region, since the current lakes and those that formed around 2300 BP do not appear to be directly linked to climatic warming. It is suggested that the most recent initiation of thermokarst activity is related to the effects of forest fires. L'origine et la croissance de nombreux lacs thermokarstiques prés de Mayo dans le Centre du Yukon ont été examinés en utilisant des observations au sol, des photographies aériennes et la dendrochronologie. Beaucoup de lacs sont en expansion, avec des vitesses d'allongement axial dépassant 1,2 m par an. Trois lacs dont les axes augmentent couramment d'environ 1 mètre par an, ont été étudiés avec un détail particulier: les analyses dendrochronologiques indiquent que ces lacs se sont formés au milieu de la deuxième partie du dernier siècle. Le profil du talik a été déterminé sous un lac, et est en accord avec la solution de Stefan pour le dégel d'un sol riche en glace avec la date de départ proposée et la vitesse d'expansion mesurée. Des horizons riches en matières organiques contenant des troncs d'arbres, des détritus végétaux et des ostracodes d'eau douce ont été mis à jour par deux slumps rétrogressifs de dégel à proximité des lacs. Ces horizons ont été interprétés comme des fonds de lacs de thermokarst antérieurs. Des dates 14C de plus ou moins 8500, 3900 et 2300 ans BP ont été obtenues indiquant plusieurs périodes d'activité failed to indicate any individuals that were more than 200 years old. |
format |
Article in Journal/Newspaper |
author |
C. R. Burn M. W. Smith |
spellingShingle |
C. R. Burn M. W. Smith Development of thermokarst lakes during the holocene at sites near Mayo, Yukon territory |
author_facet |
C. R. Burn M. W. Smith |
author_sort |
C. R. Burn |
title |
Development of thermokarst lakes during the holocene at sites near Mayo, Yukon territory |
title_short |
Development of thermokarst lakes during the holocene at sites near Mayo, Yukon territory |
title_full |
Development of thermokarst lakes during the holocene at sites near Mayo, Yukon territory |
title_fullStr |
Development of thermokarst lakes during the holocene at sites near Mayo, Yukon territory |
title_full_unstemmed |
Development of thermokarst lakes during the holocene at sites near Mayo, Yukon territory |
title_sort |
development of thermokarst lakes during the holocene at sites near mayo, yukon territory |
url |
https://doi.org/10.1002/ppp.3430010207 |
long_lat |
ENVELOPE(146.601,146.601,59.667,59.667) |
geographic |
Talik Yukon |
geographic_facet |
Talik Yukon |
genre |
Mayo Thermokarst Yukon |
genre_facet |
Mayo Thermokarst Yukon |
op_relation |
https://doi.org/10.1002/ppp.3430010207 |
op_doi |
https://doi.org/10.1002/ppp.3430010207 |
container_title |
Permafrost and Periglacial Processes |
container_volume |
1 |
container_issue |
2 |
container_start_page |
161 |
op_container_end_page |
175 |
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1766067089700814848 |