Cosmogenic exposure dating is one of the most widely used methods to constrain the deglaciation history of former glaciated areas. In Greenland, more than 1000 cosmogenic ¹⁰Be exposure ages (¹⁰Be ages) have been published within the last two decades. However, a recurring problem is that many of these studies have reported variable amounts of nuclide inheritance making the ¹⁰Be ages too old and difficult to assess without large datasets or independent age control. In this study, we test the accuracy of ¹⁰Be dating of Holocene moraines using independent age constraints from threshold lake records. In Kangerlussuaq, West Greenland, the ¹⁰Be ages of the Ørkendalen moraine system are highly clustered with a mean age of 6.8 ± 0.3 ka (no outliers). In contrast, the nearby Little Ice Age (LIA) moraine yields scattered ¹⁰Be ages ranging from 2.5 to 0.1 ka but with a mean of 0.18 ± 0.06 ka after excluding outliers which coincides with independent age constraints from threshold lakes and boulder kill dates. At Gletscherlukket, Southeast Greenland, the ¹⁰Be ages of the LIA moraine range from 10.2 to 1.6 ka with a mean of 1.9 ± 0.2 ka after excluding outliers. This is ~1.7 ka older than recorded in the proglacial threshold lakes and suggests that all samples from this site contain a significant amount of nuclide inheritance. Our results are consistent with other reports of skewed ¹⁰Be age distributions in LIA re-advance moraines and it probably reflects nuclide inheritance from exposure during the Holocene Thermal Maximum when the glaciers in Greenland were inside the LIA extent. In contrast, there is no evidence of nuclide inheritance in the Ørkendalen moraines, most likely because the glacial erosion was more intense prior to the formation of the moraines i.e. sometime between the advance phase during Last Glacial Maximum position and the subsequent lateglacial and Holocene deglaciation. Our results highlight a potential pitfall related to dating re-advance moraines using cosmogenic exposure dating and we recommend using a multi-method dating approach.

宇宙成因暴露年代测定是限制前冰川地区冰消历史的最广泛使用的方法之一。在格陵兰，过去 20 年中已发表了 1000 多个宇宙成因¹⁰ Be 暴露年龄（¹⁰ Be 年龄）。然而，一个反复出现的问题是，许多这些研究报告了不同数量的核素遗传，这使得¹⁰ Be 年龄过大，如果没有大数据集或独立的年龄控制就难以评估。在这项研究中，我们使用阈值湖泊记录的独立年龄限制来测试全新世冰碛的¹⁰ Be 年代测定的准确性。在西格陵兰的康克鲁斯瓦克，¹⁰Ørkendalen 冰碛系统的年龄高度聚集，平均年龄为 6.8 ± 0.3 ka（无异常值）。相比之下，附近的小冰河时代 (LIA) 冰碛产生分散的¹⁰ Be 年龄，范围为 2.5 至 0.1 ka，但在排除异常值后，平均值为 0.18 ± 0.06 ka，这与阈值湖泊和巨石死亡日期的独立年龄限制相吻合。在格陵兰东南部的 Gletscherlukket，LIA 冰碛的¹⁰ Be 年龄范围从 10.2 到 1.6 ka，排除异常值后的平均值为 1.9 ± 0.2 ka。这比前冰期阈值湖泊中记录的要早约 1.7 ka，表明该站点的所有样本都包含大量核素遗传。我们的结果与偏斜^{10 的}其他报告一致LIA 中的年龄分布重新推进冰碛，它可能反映了格陵兰岛冰川在 LIA 范围内时全新世热最大值期间暴露的核素遗传。相比之下，在Ørkendalen 冰碛中没有核素遗传的证据，这很可能是因为在冰碛形成之前冰川侵蚀更加强烈，即在末次冰期最大值位置的前进阶段与随后的晚冰期和全新世冰消期之间的某个时间。我们的结果突出了与使用宇宙成因暴露定年法重新推进冰碛定年相关的潜在陷阱，我们建议使用多方法定年法。