Ice wedges are considered as a paleoarchive of winter air temperatures as their stable isotope composition has been widely used to reconstruct winter climatic conditions in the Arctic regions. Ice wedge stable isotope records, obtained in recent decades for many Arctic permafrost areas of Russia and North America, demonstrate a clear shift from lower to higher values between the Late Pleistocene and Holocene (by 5–10‰ for δ¹⁸O values in some regions of the Russian Arctic), which is widely accepted as evidence of winter air temperature increase. However, the evolution of winter air temperatures during the Holocene is less clear and, according to proxy reconstructions, winter climate trends are not synchronous and may significantly vary throughout the Arctic. In this study, we investigate the stable isotope composition of Holocene syngenetic ice wedges and modern ice veinlets of northwestern Siberia. Radiocarbon dating of enclosing sediments and a few dates of organic material from ice wedges demonstrate that ice wedges grew constantly within the study area during the Holocene though early–mid-Holocene in northwestern Siberia is often considered as a thermal optimum. In fact, many proxy records indicate an increase of summer air temperatures followed by thermokarst activity, peatland formation, and northward advance of the treeline. According to our data, winter climate conditions in terms of mean air temperature of the coldest winter month (January) did not change significantly during the key Holocene stages, and during the Greenlandian and most of the Northgrippian stages (between 11.4 and 6 cal ka BP) mean January air temperature (T_mJ) varied between −21 and −30°C, and from the end of the Northgrippian, during the Meghalayan stages of Holocene (5.2–0.9 cal ka BP), T_mJ varied between −24 to −28°C. Mean January air temperature during the Holocene was generally 1–2°C lower than the modern one, meanwhile the submeridional direction of T_mJ isotherms and eastward decrease of T_mJ values in Holocene are similar to the modern pattern.

中文翻译：

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基于冰楔稳定同位素比重建西伯利亚西北部全新世1月古温度

冰楔被认为是冬季气温的古档案，因为它们的稳定同位素组成已被广泛用于重建北极地区的冬季气候条件。近几十年来在俄罗斯和北美的许多北极永久冻土区获得的冰楔稳定同位素记录表明，晚更新世和全新世之间从较低值到较高值的明显转变（δ ^{18为 5-10‰}俄罗斯北极某些地区的 O 值），这被广泛接受为冬季气温升高的证据。然而，全新世冬季气温的演变不太清楚，根据代理重建，冬季气候趋势并不同步，整个北极可能会有很大差异。在这项研究中，我们研究了西伯利亚西北部全新世同生冰楔和现代冰脉的稳定同位素组成。封闭沉积物的放射性碳年代测定和冰楔有机物质的一些日期表明，冰楔在全新世期间在研究区域内不断生长，尽管西伯利亚西北部的早中期全新世通常被认为是热最佳。实际上，许多代理记录表明夏季气温升高，随后是热岩溶活动、泥炭地形成和林线向北推进。根据我们的数据，在全新世关键阶段、格陵兰阶和北格里皮阶的大部分阶段（11.4 到 6 cal ka BP 之间），冬季最冷月份（1 月）平均气温的冬季气候条件没有发生显着变化) 一月平均气温 (T _mJ ) 在-21 到-30°C 之间变化，从北格里皮阶末期开始，在全新世的梅加拉延期 (5.2–0.9 cal ka BP)，T _mJ在-24 到-28°C 之间变化。全新世1月平均气温普遍比现代低1~2℃，同时全新世T _mJ等温线的次午线方向和T _mJ值向东递减的趋势与现代相似。