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This dataset documents the occurrence, distribution, and characteristics of cryptic ice wedge networks in the Yukon-Kuskokwim Delta (YKD), Alaska. The dataset is derived from remote sensing analyses, field-based permafrost coring, ground-penetrating radar (GPR) surveys, and stable water isotope analyses. High-resolution aerial orthoimagery from 2018 enabled the identification of ~50 linear kilometers (km) of ice wedge trough networks within a 60 square kilometers (km²) study area near Bethel, Alaska, revealing ice wedge networks previously undocumented in the region. Fieldwork in 2023 and 2024 confirmed the presence of ice wedges up to 1.5 meter (m) wide and 2.5 m tall, with wedge tops averaging 0.9 m below the surface. GPR transects identified additional ice wedges beyond those visible in imagery, suggesting that remote sensing analyses may underestimate their true abundance. Coring of polygon centers revealed a suite of late-Quaternary deposits, including early Holocene peat, ice-rich late-Pleistocene permafrost (reworked Yedoma), charcoal layers indicating past tundra fires, and the Aniakchak CFE II tephra (~3,600 calendar years before present [cal yrs BP]). Stable water isotope analyses of wedge ice (mean δ¹⁸O = -15.7 ‰, δ²H = -113.1 ‰) indicate relatively enriched values compared to other Holocene ice wedges in Alaska, reflecting the region's warm maritime climate influence. Expanding the mapping analysis across the YKD using very high-resolution satellite imagery, we found that 95 % of observed ice wedge networks occur at elevations between 4 and 80 meters above sea level (m asl), predominantly within tundra vegetation classes. These areas, covering ~32 % of the YKD tundra region, may contain additional ice wedges, peat deposits, and relict Yedoma. This dataset provides a new framework for understanding the spatial distribution and environmental controls on ice wedge development in warm permafrost regions, with implications for permafrost resilience, climate change vulnerability, and land use planning in the YKD.
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Cryptic Ice Wedge Networks in Holocene Peat, Yukon‐Kuskokwim Delta, Alaska
ABSTRACT The Yukon‐Kuskokwim Delta (YKD), covering ~75,000 km2of Alaska's discontinuous permafrost zone, has a historic (1902–2023) mean annual air temperature of ~−1°C and was previously thought to lack ice wedge networks. However, our recent investigations near Bethel, Alaska, revealed numerous near‐surface ice wedges. Using 20 cm resolution aerial orthoimagery from 2018, we identified ~50 linear km of ice wedge troughs in a 60 km2study area. Fieldwork in 2023 and 2024 confirmed ice wedges up to ~1.5 m wide and ~2.5 m in vertical extent, situated on average 0.9 m below the tundra surface (n = 29). Ground‐penetrating radar (GPR) detected additional ice wedges beyond those visible in the remote sensing imagery, suggesting an underestimation of their true abundance. Coring of polygonal centers revealed late‐Quaternary deposits, including thick early Holocene peat, late‐Pleistocene ice‐rich silts (reworked Yedoma), charcoal layers from tundra fires, and the Aniakchak CFE II tephra (~3600 cal yrs BP). Stable water isotopes from Bethel's wedge ice (mean δ18O = −15.7 ‰, δ2H = −113.1 ‰) indicate a relatively enriched signature compared to other Holocene ice wedges in Alaska, likely due to warmer temperatures and maritime influences. Expanding our mapping across the YKD using high‐resolution satellite imagery from 2012 to 2024, we estimate that the Holocene ice wedge zone encompasses ~30% of the YKD tundra region. Our findings demonstrate that ice wedge networks are more widespread across the YKD than previously recognized, emphasizing both the resilience and vulnerability of the region's warm, ice‐rich permafrost. These insights are crucial for understanding permafrost responses to climate change and assessing agricultural potential and development in the region.
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- PAR ID:
- 10613072
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Permafrost and Periglacial Processes
- Volume:
- 36
- Issue:
- 4
- ISSN:
- 1045-6740
- Format(s):
- Medium: X Size: p. 678-701
- Size(s):
- p. 678-701
- Sponsoring Org:
- National Science Foundation
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