We evaluate the timing and environmental controls on past rock-glacier activity at Øyberget, upper Ottadalen, southern Norway, using in situ 10Be surface-exposure dating on (1) boulders belonging to relict rock-glacier lobes at c. 530 m asl, (2) bedrock and boulder surfaces at the Øyberget summit (c. 1200 m asl), and (3) bedrock at an up-valley site (c. 615 m asl). We find that the rock-glacier lobes became inactive around 11.1 ± 1.2 ka, coeval with the timing of summit deglaciation (11.2 ± 0.7 ka). This is slightly older than previously published Schmidt-hammer surface-exposure ages. The timing does not match known climatic conditions promoting rock-glacier formation in the early Holocene; hence we infer that lobe formation resulted from enhanced debris supply and burial of residual ice during and soon after deglaciation. The results demonstrate that rock glaciers may form over a relatively short period of time (hundreds rather than thousands of years) under non-permafrost conditions and possibly indicate a paraglacial type of process.

中文翻译：

---

来自 10Be 表面暴露测年的挪威南部岩石冰川在冰川旁快速形成的证据

我们使用原位评估了挪威南部上奥塔达伦的 Øyberget 过去岩石冰川活动的时间和环境控制10对 (1) 属于 c 处残留岩石-冰川裂片的巨石进行表面暴露测年。530 m asl，（2）Øyberget 山顶的基岩和巨石表面（c. 1200 m asl），以及（3）山谷上方的基岩（c. 615 m asl）。我们发现岩石-冰川裂片在 11.1 ± 1.2 ka 左右变得不活跃，与山顶冰川消融的时间（11.2 ± 0.7 ka）同时发生。这比之前公布的施密特锤表面暴露年龄稍早。时间与促进全新世早期岩石冰川形成的已知气候条件不匹配；因此，我们推断裂片的形成是由于在消冰期间和之后不久增加的碎片供应和残留冰的埋藏造成的。