The century-long 8.2 ka cold event interrupted early Holocene boreal warmth and may have halted retreat of Greenland ice-sheet margins during the last deglaciation. Here, we synthesize new and existing glacial geological data to assess the behavior of the southwest Greenland ice sheet during the 8.2 ka cold event. In southwest Greenland near the town of Kangerlussuaq, existing and new ¹⁰Be surface exposure ages demonstrate that deposition of the Keglen moraines ended at 8.0 ± 0.1 ka (n = 10, 1 outlier), with prior studies arguing that these moraines represented an ice-margin stillstand in response to the 8.2 ka cold event. However, new ¹⁰Be ages show that the southwest Greenland ice-sheet margin retreated from the Umîvît moraines, which lie 5–10 km outboard of the Keglen moraines, at 8.2 ± 0.2 ka (n = 11). Accordingly, we suggest that the southwest Greenland ice-sheet margin in the Kangerlussuaq region retreated 5–10 km during the 8.2 ka cold event. Farther south and inland from Nuuk, new ¹⁰Be boulder-on-bedrock ages adjacent to the modern ice-sheet margin demonstrate that the ice-margin was retreating with no moraine deposition at 8.2 ± 0.1 ka (n = 4, 1 outlier), with this retreat continuing up to at least ∼7.5 ka according to an existing threshold lake record. Therefore, we propose that the southwest Greenland ice-sheet margin underwent continued retreat during the 8.2 ka cold event in response to elevated early Holocene boreal summer insolation that overwhelmed the impacts from century-scale cooling. Caution should be used in assuming climatic causation for moraine deposition based on temporal correlation.

长达一个世纪的 8.2 ka 寒冷事件中断了全新世早期的北方温暖，并可能在最后一次冰消期间停止了格陵兰冰盖边缘的退缩。在这里，我们综合了新的和现有的冰川地质数据，以评估格陵兰岛西南部冰盖在 8.2 ka 冷事件期间的行为。在康克鲁斯瓦克镇附近的格陵兰西南部，现有的和新的¹⁰ Be 表面暴露年龄表明，凯格伦冰碛的沉积结束于 8.0 ± 0.1 ka（n = 10，1 个异常值），先前的研究认为这些冰碛代表了冰- 8.2 ka 冷事件的利润率仍然存在。然而，新的¹⁰Be 年龄表明格陵兰岛西南部冰盖边缘从位于 Keglen 冰碛外侧 5-10 公里处的 Umîvît 冰碛退缩，温度为 8.2 ± 0.2 ka（n = 11）。因此，我们认为在 8.2 ka 冷事件期间，Kangerlussuaq 地区的西南格陵兰冰盖边缘退缩了 5-10 km。从努克向南和内陆，新的¹⁰与现代冰盖边缘相邻的基岩上的巨石年龄表明，冰边缘在 8.2 ± 0.1 ka（n = 4，1 个异常值）处没有冰碛沉积，并且这种后退持续至少 ∼ 7.5 ka 根据现有的阈值湖泊记录。因此，我们认为格陵兰岛西南部冰盖边缘在 8.2 ka 冷事件期间经历了持续的后退，以应对全新世早期北方夏季日照升高，从而压倒了世纪尺度冷却的影响。在基于时间相关性假设冰碛沉积的气候原因时应谨慎。