Abstract Glacial Lake Outburst Floods (GLOFs) constitute a major threat in glacierized regions. Despite a recent increase in the size and number of glacial lakes worldwide, there is only limited evidence that climate change is affecting GLOF frequency. GLOFs are particularly common in the Baker River watershed (Patagonia, 47°S), where 21 GLOFs occurred between 2008 and 2017 due to the drainage of Cachet 2 Lake into the Colonia River, a tributary of the Baker River. During these GLOFs, the increased discharge from the Colonia River blocks the regular flow of the Baker River, resulting in the inundation of the Valle Grande floodplain, which is located approximately 4 km upstream of the confluence. To assess the possible relationship between GLOF frequency and climate variability, four sediment cores collected in the Valle Grande floodplain were analyzed. Their geophysical and sedimentological properties were examined, and radiocarbon-based age-depth models were constructed. All cores consist of dense, fine-grained, organic-poor material alternating with low-density organic-rich deposits. The percentage of lithogenic particles, which were most likely deposited during high-magnitude GLOFs, was used to reconstruct the flood history of the last 2.75 kyr. Results show increased flood activity between 2.57 and 2.17 cal kyr BP, and between 0.75 and 0 cal kyr BP. These two periods coincide with Neoglacial advances that are coeval with periods of lower temperature and increased precipitation. Our results suggest that GLOFs are not a new phenomenon in the region. Although rapid glacier retreat is likely responsible for high GLOF frequency in the 21st century, high-magnitude GLOFs seem to occur more frequently when glaciers are larger and thicker.

中文翻译：

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智利巴塔哥尼亚贝克河上游高强度冰川湖爆发洪水频率的新冰期增加（47°S）

摘要 冰川湖溃决洪水（GLOFs）是冰川地区的主要威胁。尽管最近全世界冰川湖的规模和数量都有所增加，但只有有限的证据表明气候变化正在影响 GLOF 频率。GLOF 在贝克河流域（巴塔哥尼亚，南纬 47°）特别常见，由于 Cachet 2 湖排入贝克河的支流科洛尼亚河，2008 年至 2017 年间发生了 21 次 GLOF。在这些 GLOF 期间，科洛尼亚河的流量增加阻碍了贝克河的正常流动，导致位于汇流处上游约 4 公里的大山谷洪泛区被淹没。为了评估 GLOF 频率与气候变率之间可能的关系，分析了在 Valle Grande 洪泛区收集的四个沉积物岩心。研究了它们的地球物理和沉积学特性，并构建了基于放射性碳的年龄深度模型。所有岩心均由致密、细粒、贫有机质材料与低密度富含有机质沉积物交替组成。最有可能在高震级 GLOF 期间沉积的成岩颗粒的百分比被用来重建最后 2.75 kyr 的洪水历史。结果显示在 2.57 和 2.17 cal kyr BP 之间以及在 0.75 和 0 cal kyr BP 之间洪水活动增加。这两个时期与新冰期的进展相吻合，新冰期的进展与低温和降水增加的时期同时发生。我们的结果表明 GLOF 在该地区并不是一个新现象。