Ice wedges as archives of winter paleoclimate: A review

Ice‐wedge ice can provide a valuable record of past winter climate variability at high latitudes yet to date this proxy has been applied only sparsely across the Chukotka region of Siberia. Here we present data from eight ice‐wedges at four sites across a 600‐km transect in Eastern Chukotka which we use to reconstruct regional Holocene winter paleotemperature. The Holocene age of ice‐wedges was established by radiocarbon dating of peat surrounding individual ice‐wedges. Our suite of radiocarbon ages suggests that the studied ice‐wedges formed between 12.9–11.8 and 3–2.5 cal ka BP. δ18O and δ2H values from ice‐wedge ice indicate that in coastal areas of Eastern Chukotka mean January air temperatures in the first half of the Holocene were on average 2–3°С lower than modern values, a finding that corresponds well with winter climate reconstructions for the other areas of Beringia. The variability of reconstructed mean January air temperatures in the study area did not exceed 2–4°C during the early to mid‐Holocene.

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See 3 more Smart Citations

Isotopic evidence for Holocene January air temperature variability on the East Chukotka Peninsula

Vasil'chuk

Budantseva

Farquharson

et al. 2018

Recent advances in paleoclimatological studies of Arctic wedge‐ and pore‐ice stable‐water isotope records

Porter

Opel

2020

Late Pleistocene and Holocene ground ice are common throughout the Arctic. Some forms 12 of relict ground ice preserve local meteoric water, and their stable oxygen-and hydrogen-13 isotope ratios can be used to reconstruct past air temperatures. In this paper, we review the 14 formation and sampling of two forms of relict ground ice -wedge ice and pore ice -and 15 recent (2010-2019) advances in paleoclimatological studies of ground-ice stable-isotope 16 records in the Arctic. Recent advances are attributed to better chronological constraints and 17 refined understandings of the systematics and seasonality of relict wedge ice and pore ice. A 18 rich network of ice-wedge records has emerged, primarily from the Siberian Arctic, whereas 19 pore-ice records are less common. The ice-wedge network depicts a robust pattern of late 20 Pleistocene cooling, and remarkably similar temperature depressions during Marine Isotope 21 Stages 3 and 2. Very high-resolution wedge-and pore-ice stable isotope chronologies have 22 been established recently and used to reconstruct winter and summer climate histories and 23 assess seasonal dependencies in insolation-forced climate. Reports of ancient (>125 ka BP) 24 ground ice demonstrate the long-term persistence of relict ground ice, and its potential to 25 expand our knowledge of Quaternary climate dynamics in the terrestrial Arctic.

Holocene pore‐ice δ¹⁸O and δ²H records from drained thermokarst lake basins in the Old Crow Flats, Yukon, Canada

Bandara

Froese

Porter

et al. 2020

Thermokarst lakes form following the thaw of ice-rich permafrost and drain after a few decades to millennia. Drained thermokarst lake basins (DTLBs) become epicenters for peat accumulation and re-aggradation of ice-rich permafrost. This reaggradation of permafrost may be interrupted by subsequent thermokarst lake formation with sufficient disturbance. Thermokarst lakes and DTLBs are abundant near Old Crow, Yukon, Canada, but little is known about their evolution through the Holocene. In this study, we investigate the hydrology and drainage histories of seven DTLBs from the Old Crow Flats on the basis of cryostratigraphy, radiocarbon dating, and pore-ice δ 18 O and δ 2 H records. Cryostratigraphic evidence implies only one of the seven studied DTLBs underwent multiple thermokarst cycles. Radiocarbon agedepth models demonstrate a slowdown in the rate of post-drainage peat accumulation with time. Pore-ice isotope analyses reveal a spectrum of possible post-drainage isotopic histories resulting from spatial variability in permafrost, vegetation, and hydrology. Unlike lacustrine silt, post-drainage peat contains relatively constant poreice isotope trends. In light of our findings, we propose that syngenetic peat permafrost in DTLBs preserve a warm-season sampling of local meteoric waters. These pore-ice δ 18 O and δ 2 H records may aid millennial-scale paleoclimate investigations, as we demonstrate through our reconstruction of Holocene climate change in northern Yukon.