Lake sediment records give valuable insight into the dynamic events that characterized the last deglaciation in Iceland. Here, we focus on the well-dated sediment record from Hestvatn, a low-elevation lake in south Iceland, that features six graded bedding events deposited by outburst floods from glacial lakes dammed by the decaying Iceland Ice Sheet (IIS) in the time period of the Vedde Ash and the G10ka Series tephra. Using climate proxies preserved in the sediment cores, in conjunction with regional glacial geomorphology, we reconstruct the retreat of the IIS in south Iceland, from a marine-based glacier during the Younger Dryas to a land-based glacier during the Preboreal. As the ice sheet margin withdrew to the central highlands, ice-dammed lakes formed along glacier margins. The ice-dams were occasionally breached, generating large-scale jökulhlaups (catastrophic outburst floods) that deposited thick turbidite sequences preserved in the sediment record of Hestvatn. The high concentration of volcanic material incorporated within deglacial sediments indicates that along with IIS retreat, subglacial volcanic activity may have helped initiate some of the jökulhlaups. Onset of more stable Holocene conditions was reached after the final turbidite at ~10 ka bp, when the IIS had withdrawn from most of the highlands of Iceland.

中文翻译：

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冰岛南部新仙女木 - 早期全新世冰川消退期间反复爆发的洪水和爆发性火山活动：来自湖泊记录的证据

湖泊沉积物记录为了解冰岛最后一次冰川消融的动态事件提供了宝贵的见解。在这里，我们专注于来自冰岛南部低海拔湖泊 Hestvatn 的年代久远的沉积物记录，该记录具有六个分级层理事件，这些事件是由在该时间段内被腐烂的冰岛冰盖 (IIS) 阻挡的冰川湖的爆发洪水沉积的Vedde Ash 和 G10ka 系列 tephra。利用沉积物核心中保存的气候代理，结合区域冰川地貌，我们重建了冰岛南部 IIS 的退缩，从新仙女木时期的海洋冰川到前寒带时期的陆地冰川。随着冰盖边缘向中央高地退去，冰川边缘形成了冰坝湖泊。冰坝偶尔会被破坏，产生大规模jökulhlaups（灾难性爆发洪水），沉积厚厚的浊积岩序列，保存在Hestvatn的沉积物记录中。冰川沉积物中火山物质的高浓度表明，随着 IIS 的退缩，冰下火山活动可能有助于引发一些 jökulhlaups。在~10 ka 的最终浊积之后达到更稳定的全新世条件的开始bp，当 IIS 从冰岛的大部分高地撤出时。