Over the past few decades, the δ¹⁸O records of ice wedges have been used to estimate late Quaternary winter air temperatures. This study first reviews the development of ice wedges and the potential isotopic fractionation that takes place from snow deposition to formation of ice veinlets. Then, based on the high resolution analysis of ice wedges from the Eureka Sound Lowland (Ellesmere and Axel Heiberg Islands), we evaluate the effect of sampling depth and edge effects on the δ¹⁸O records and compare a composite δ¹⁸O time-series of ice wedges to the Holocene 25-yr annual and 20-yr winter δ¹⁸O records of the nearby Agassiz Ice Cap. Radiocarbon ages of dissolved organic carbon in ice wedges showed that cracking occurs mostly near the center of the wedge, but age reversals were observed. Covariance analysis showed that two δ¹⁸O profiles collected at the same depth had high noise (c. 70–80 % uncorrelated parts). Additionally, ice wedge mean δ¹⁸O records showed a decreasing trend with depth, likely due Rayleigh fractionation during freezing of residual water in the crack. Finally, the composite δ¹⁸O time-series of ice wedges and δ¹⁸O records of the Agassiz Ice Cap showed a similar Holocene cooling trend, however the wedges δ¹⁸O records had a higher degree of variability throughout the Holocene (∼4 ‰ versus ∼2 ‰ in the Agassiz records). The higher variability in the wedge is attributed to the timing of meltwater infiltrating the wedge crack over the growth period, which from the onset to termination of snowmelt, is in the order of 3–6‰. The study highlights that, if to be used as a centennial-millennial scale proxy, ice wedges should be sampled near the surface where δ¹⁸O records would be less affected by in situ freezing and plugging, and veinlets should be dated directly and smoothed to remove the local random variance.

在过去的几十年中，冰楔的 δ ¹⁸ O 记录已被用于估计晚第四纪冬季气温。本研究首先回顾了冰楔的发展以及从积雪到冰脉形成过程中可能发生的同位素分馏。然后，基于对尤里卡海峡低地（埃尔斯米尔岛和阿克塞尔海伯格群岛）冰楔的高分辨率分析，我们评估了采样深度和边缘效应对 δ ¹⁸ O 记录的影响，并比较了复合 δ ¹⁸ O 时间序列到全新世 25 年和 20 年冬季的冰楔δ ¹⁸附近阿加西冰帽的 O 记录。冰楔中溶解有机碳的放射性碳年龄表明，裂纹主要发生在楔子的中心附近，但观察到年龄逆转。协方差分析表明，在相同深度收集的两个 δ ¹⁸ O 剖面具有高噪声（大约 70-80% 不相关部分）。此外，冰楔平均 δ ¹⁸ O 记录显示出随深度下降的趋势，这可能是由于裂缝中残留水冻结过程中的瑞利分馏。最后，冰楔的复合δ ¹⁸ O时间序列和Agassiz冰帽的δ ¹⁸ O记录显示出类似的全新世冷却趋势，但楔形δ ¹⁸O 记录在整个全新世中具有更高程度的变异性（~4 ‰ vs Agassiz 记录中的~2 ‰）。楔形较高的变异性归因于融水在生长期间渗入楔形裂缝的时间，从融雪开始到结束，大约为 3–6‰。该研究强调，如果要用作百年-千年尺度代理，应在地表附近对冰楔进行采样，在那里 δ ¹⁸ O 记录受原位冻结和堵塞的影响较小，并且细脉应直接测年并平滑至去除局部随机方差。