Abstract In the changing glacierized areas of the maritime Arctic region, fluxes of sediments are of high intensity during the Arctic melting season. On the Western Spitsbergen Island around Gronfjord, several glaciers have declined rapidly over the last century. The Aldegonda Glacier has retreated about 2 km since 1911 when the glacier tongue reached the seashore which lead to new exposed surfaces in the proglacial area supplying sediments to the fjord during the arctic summer. We explored if the geochemical signature of sediments can be used to discriminate sediment provenance in proglacial environments during different stages of the melting season. To this purpose a sampling campaign was undertaken in July 2015 in the Aldegonda Glacier area, to obtain 24 composite surface samples of moraine materials and sediments at the glacier surface and 12 sediment mixtures. Fingerprinting techniques were applied to determine the sediment provenance and tracers were selected using a novel conservative index and consensus ranking method. FingerPro model identified bottom moraines as predominant source in all cases (74%), recent moraines amounted to 15% and sediment on ice contributed 11%. Radionuclide signatures were of great value to identify sediment provenance, and 137Cs and 210Pbex were among the most selected tracers. Variations in source contributions depended on the location and type of the sediment mixtures. Differences in source contributions also varied temporarily suggesting different sediment mobilization processes during snow and ice melt. Snow and ice melt are the main drivers of sediment mobilization contributed from moraines during summer. Moreover, sediments accumulated on the glacier surface including cryoconite, deliver radionuclides and heavy metals associated to fine particles that have an impact on terrestrial and sea arctic ecosystems. Such deleterious impact could be one main effect of climate change on glacierized environments worldwide.

中文翻译：

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使用放射性核素和元素指纹揭示冰川退缩后冰碛复合体 Aldegonda 冰川（斯瓦尔巴群岛）中沉积物的来源

摘要 在不断变化的北极海域冰川区，在北极融化季节，沉积物的流动强度很大。在格隆峡湾附近的西斯匹次卑尔根岛，上个世纪，几条冰川迅速消退。自 1911 年冰川舌到达海岸以来，阿尔德贡达冰川已经后退约 2 公里，这导致前冰区出现新的裸露表面，在北极夏季为峡湾提供沉积物。我们探讨了沉积物的地球化学特征是否可用于区分融化季节不同阶段前冰期环境中的沉积物来源。为此，2015 年 7 月在阿尔德贡达冰川地区开展了抽样活动，获得冰川表面冰碛物质与沉积物复合表面样品24个，沉积物混合物12个。应用指纹技术确定沉积物来源，并使用新的保守指数和共识排序方法选择示踪剂。FingerPro 模型将底部冰碛确定为所有情况下的主要来源 (74%)，最近的冰碛占 15%，冰上沉积物占 11%。放射性核素特征对于识别沉积物来源具有重要价值，137Cs 和 210Pbex 是选择最多的示踪剂之一。源贡献的变化取决于沉积物混合物的位置和类型。源贡献的差异也暂时变化，表明冰雪融化期间不同的沉积物动员过程。冰雪融化是夏季冰碛沉积物动员的主要驱动力。此外，积聚在冰川表面的沉积物，包括冰尘，提供放射性核素和重金属，这些微粒与对陆地和海洋北极生态系统产生影响的细颗粒相关。这种有害影响可能是气候变化对全球冰川环境的主要影响之一。