Holocene Thermokarst Lake Dynamics in Northern Interior Alaska: The Interplay of Climate, Fire, and Subsurface Hydrology
The current state of permafrost in Alaska and meaningful expectations for its future evolution are informed by long-term perspectives on previous permafrost degradation. Thermokarst processes in permafrost landscapes often lead to widespread lake formation and the spatial and temporal evolution of t...
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ftdoajarticles:oai:doaj.org/article:5e643f72aa584b78a3aaed49522352c9 2023-05-15T17:57:08+02:00 Holocene Thermokarst Lake Dynamics in Northern Interior Alaska: The Interplay of Climate, Fire, and Subsurface Hydrology Lesleigh Anderson Mary Edwards Mark D. Shapley Bruce P. Finney Catherine Langdon 2019-04-01T00:00:00Z https://doi.org/10.3389/feart.2019.00053 https://doaj.org/article/5e643f72aa584b78a3aaed49522352c9 EN eng Frontiers Media S.A. https://www.frontiersin.org/article/10.3389/feart.2019.00053/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2019.00053 https://doaj.org/article/5e643f72aa584b78a3aaed49522352c9 Frontiers in Earth Science, Vol 7 (2019) Alaska Holocene permafrost thermokarst lakes lake levels paleoclimate Science Q article 2019 ftdoajarticles https://doi.org/10.3389/feart.2019.00053 2022-12-31T09:29:58Z The current state of permafrost in Alaska and meaningful expectations for its future evolution are informed by long-term perspectives on previous permafrost degradation. Thermokarst processes in permafrost landscapes often lead to widespread lake formation and the spatial and temporal evolution of thermokarst lake landscapes reflects the combined effects of climate, ground conditions, vegetation, and fire. This study provides detailed analyses of thermokarst lake sediments of Holocene age from the southern loess uplands of the Yukon Flats, including bathymetry and sediment core analyses across a water depth transect. The sediment core results, dated by radiocarbon and 210Pb, indicate the permanent onset of finely laminated lacustrine sedimentation by ∼8,000 cal yr BP, which followed basin development through inferred thermokarst processes. Thermokarst expansion to modern shoreline configurations continued until ∼5000 cal yr BP and may have been influenced by increased fire. Between ∼5000 and 2000 cal yr BP, the preservation of fine laminations at intermediate and deep-water depths indicate higher lake levels than present. At that time, the lake likely overflowed into an over-deepened gully system that is no longer occupied by perennial streams. By ∼2000 cal yr BP, a shift to massive sedimentation at intermediate water depths indicates that lake levels lowered, which is interpreted to reflect a response to drier conditions based on correspondence with Yukon Flats regional fire and local paleoclimate reconstructions. Consideration of additional contributing mechanisms include the possible influence of catastrophic lake drainages on down-gradient base-flow levels that may have enhanced subsurface water loss, although this mechanism is untested. The overall consistency between the millennial lake-level trends documented here with regional paleoclimate trends indicates that after thermokarst lakes formed, their size and depth has been affected by North Pacific atmospheric circulation in addition to the evolution of ... Article in Journal/Newspaper permafrost Thermokarst Alaska Yukon Directory of Open Access Journals: DOAJ Articles Pacific Yukon Frontiers in Earth Science 7 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Alaska Holocene permafrost thermokarst lakes lake levels paleoclimate Science Q |
spellingShingle |
Alaska Holocene permafrost thermokarst lakes lake levels paleoclimate Science Q Lesleigh Anderson Mary Edwards Mark D. Shapley Bruce P. Finney Catherine Langdon Holocene Thermokarst Lake Dynamics in Northern Interior Alaska: The Interplay of Climate, Fire, and Subsurface Hydrology |
topic_facet |
Alaska Holocene permafrost thermokarst lakes lake levels paleoclimate Science Q |
description |
The current state of permafrost in Alaska and meaningful expectations for its future evolution are informed by long-term perspectives on previous permafrost degradation. Thermokarst processes in permafrost landscapes often lead to widespread lake formation and the spatial and temporal evolution of thermokarst lake landscapes reflects the combined effects of climate, ground conditions, vegetation, and fire. This study provides detailed analyses of thermokarst lake sediments of Holocene age from the southern loess uplands of the Yukon Flats, including bathymetry and sediment core analyses across a water depth transect. The sediment core results, dated by radiocarbon and 210Pb, indicate the permanent onset of finely laminated lacustrine sedimentation by ∼8,000 cal yr BP, which followed basin development through inferred thermokarst processes. Thermokarst expansion to modern shoreline configurations continued until ∼5000 cal yr BP and may have been influenced by increased fire. Between ∼5000 and 2000 cal yr BP, the preservation of fine laminations at intermediate and deep-water depths indicate higher lake levels than present. At that time, the lake likely overflowed into an over-deepened gully system that is no longer occupied by perennial streams. By ∼2000 cal yr BP, a shift to massive sedimentation at intermediate water depths indicates that lake levels lowered, which is interpreted to reflect a response to drier conditions based on correspondence with Yukon Flats regional fire and local paleoclimate reconstructions. Consideration of additional contributing mechanisms include the possible influence of catastrophic lake drainages on down-gradient base-flow levels that may have enhanced subsurface water loss, although this mechanism is untested. The overall consistency between the millennial lake-level trends documented here with regional paleoclimate trends indicates that after thermokarst lakes formed, their size and depth has been affected by North Pacific atmospheric circulation in addition to the evolution of ... |
format |
Article in Journal/Newspaper |
author |
Lesleigh Anderson Mary Edwards Mark D. Shapley Bruce P. Finney Catherine Langdon |
author_facet |
Lesleigh Anderson Mary Edwards Mark D. Shapley Bruce P. Finney Catherine Langdon |
author_sort |
Lesleigh Anderson |
title |
Holocene Thermokarst Lake Dynamics in Northern Interior Alaska: The Interplay of Climate, Fire, and Subsurface Hydrology |
title_short |
Holocene Thermokarst Lake Dynamics in Northern Interior Alaska: The Interplay of Climate, Fire, and Subsurface Hydrology |
title_full |
Holocene Thermokarst Lake Dynamics in Northern Interior Alaska: The Interplay of Climate, Fire, and Subsurface Hydrology |
title_fullStr |
Holocene Thermokarst Lake Dynamics in Northern Interior Alaska: The Interplay of Climate, Fire, and Subsurface Hydrology |
title_full_unstemmed |
Holocene Thermokarst Lake Dynamics in Northern Interior Alaska: The Interplay of Climate, Fire, and Subsurface Hydrology |
title_sort |
holocene thermokarst lake dynamics in northern interior alaska: the interplay of climate, fire, and subsurface hydrology |
publisher |
Frontiers Media S.A. |
publishDate |
2019 |
url |
https://doi.org/10.3389/feart.2019.00053 https://doaj.org/article/5e643f72aa584b78a3aaed49522352c9 |
geographic |
Pacific Yukon |
geographic_facet |
Pacific Yukon |
genre |
permafrost Thermokarst Alaska Yukon |
genre_facet |
permafrost Thermokarst Alaska Yukon |
op_source |
Frontiers in Earth Science, Vol 7 (2019) |
op_relation |
https://www.frontiersin.org/article/10.3389/feart.2019.00053/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2019.00053 https://doaj.org/article/5e643f72aa584b78a3aaed49522352c9 |
op_doi |
https://doi.org/10.3389/feart.2019.00053 |
container_title |
Frontiers in Earth Science |
container_volume |
7 |
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1766165508794613760 |