Permafrost is widely present throughout the Northern Hemisphere high latitudes, and stores large amounts of carbon in the form of frozen soil organic matter. The response of permafrost regions to anthropogenic climate change remains uncertain, in part because of a lack of information on their response to past changes in global climate. Here we test the use of stalagmites from two caves in Siberia as a novel, precisely dated, and highly localised archive of past permafrost carbon cycle dynamics. Stalagmite growth at these sites is controlled by the presence/absence of permafrost above the cave over glacial-interglacial time scales. We target the transition layer between two subsequent growth phases (interglacials) and the interval directly following growth resumption after the last glacial in three stalagmites, as this is where a geochemical imprint of thaw-related processes in the frozen zone between surface and cave would be recorded. We apply a multi-proxy approach including carbon isotopes (δ¹³C and ¹⁴C) and trace element concentrations, combined with petrographic analyses and high-resolution U-Th chronology. Our dataset indicates complex growth patterns and possible intervals of microbial colonisation of the stalagmite surface in the transition layers. High-resolution U-Th ages confirm that the transition layer is not a single, long growth hiatus, but rather a period of extremely slow or episodic growth phases, possibly during “skipped” interglacials. However, we find no conclusive evidence for a geochemical signature related to permafrost degradation and related local carbon cycle dynamics, which might be related to insufficient sensitivity of the archive for high-frequency processes and/or insufficient measurement resolution.

永久冻土广泛存在于北半球高纬度地区，并以冷冻土壤有机物的形式储存大量的碳。多年冻土地区对人为气候变化的反应仍然不确定，部分原因是缺乏关于它们对过去全球气候变化反应的信息。在这里，我们测试了来自西伯利亚两个洞穴的石笋作为新颖，精确且高度本地化的过去多年冻土碳循环动力学的档案的用途。这些地点的石笋的生长受冰川-冰川间时间尺度上洞穴上方是否存在永久冻土的控制。我们以三个石笋中最后一个冰期之后的恢复生长之后的两个后续生长期（间冰期）之间的过渡层为目标，因为这是在地面和洞穴之间的冻结带中融化相关过程的地球化学烙印的地方。我们采用包括碳同位素（δ¹³ C和¹⁴ C）和痕量元素的浓度，结合岩相分析和高分辨率U-Th年表。我们的数据集显示了过渡层中石笋表面的复杂生长模式和微生物定殖的可能间隔。高分辨率的U-Th年龄证实过渡层不是一个单一的，长期的生长裂隙，而是一个极其缓慢或偶发的生长阶段，可能是在“跳过”的间冰期。但是，我们没有发现与多年冻土退化和相关的局部碳循环动力学有关的地球化学特征的确凿证据，这可能与档案库对高频过程的敏感性不足和/或测量分辨率不足有关。