Abstract Holocene development of a composite alpine alluvial fan is reconstructed and dated based on its geomorphology and Schmidt-hammer exposure-age dating (SHD), supplemented by terrestrial cosmogenic-nuclide dating (TCND), lichenometry, radiocarbon dating, soil development, and palaeohydrological analysis. SHD ages of 7080 ± 450 to 8220 ± 440 years and a TCND age of 6075 ± 1220 years from the fan surface indicate that fan aggradation occurred in the early Holocene through episodic debris floods (phase 1) in response to paraglacial processes following deglaciation of the catchment (~9.7 ka). Stabilisation during the Holocene Thermal Maximum (phase 2) was followed by re-activation of the fan, involving entrenchment and terrace formation (phase 3), which occurred in response to neoglaciation after ~5.5 ka and culminated in the Little Ice Age. The main control on fan development was the effect of the changing extent of glaciers in the catchment on sediment supply, initially evinced in high-magnitude debris floods (hyperconcentrated flows) and later in water floods (typical fluvial processes). Aggradation switched to stabilisation as paraglacial activity waned, while later entrenchment was associated with relatively low bedload. Results provide the basis of a conceptual model of alluvial fan evolution for glacierized catchments related to Holocene environmental change.

中文翻译：

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基于表面暴露年龄测年技术的全新世冰川喂养复合冲积扇的开发：Illåe 扇，尤通黑门山，挪威

摘要 基于地貌和 Schmidt-hammer 暴露年龄（SHD），并辅以陆地宇宙成因-核素测年（TCND）、地衣测定、放射性碳测年、土壤发育和古水文测年，对复合高山冲积扇全新世发育进行重建和测年。分析。SHD 年龄为 7080 ± 450 至 8220 ± 440 年，TCND 年龄为 6075 ± 1220 年，表明扇面在全新世早期通过偶发性碎屑洪水（第 1 阶段）发生，以响应冰川消融后的冰河过程。集水区（~9.7 ka）。在全新世热最大值（第 2 阶段）期间稳定之后，风扇重新激活，包括堑壕和阶地形成（第 3 阶段），这是响应约 5.5 ka 之后的新冰川作用而发生的，并在小冰河时代达到顶峰。扇发展的主要控制是流域冰川范围变化对沉积物供应的影响，最初表现在高强度泥石流（超浓缩流）和后来的水淹（典型的河流过程）中。随着冰河活动减弱，加剧转变为稳定，而后来的壕沟与相对较低的床负荷有关。结果为与全新世环境变化相关的冰川集水区冲积扇演化的概念模型提供了基础。而后来的防御工事与相对较低的床负荷有关。结果为与全新世环境变化相关的冰川集水区冲积扇演化的概念模型提供了基础。而后来的防御工事与相对较低的床负荷有关。结果为与全新世环境变化相关的冰川集水区冲积扇演化的概念模型提供了基础。