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DOI10.1016/j.geomorph.2024.109184
Geomorphological signature of topographically controlled ice flow-switching at a glacier margin: Breiðamerkurjokull (Iceland) as a modern analogue for palaeo-ice sheets
发表日期2024
ISSN0169-555X
EISSN1872-695X
起始页码454
卷号454
英文摘要Ice low-switching, which can involve changes in ice flow velocity and direction, is crucial to a full understanding of ice masses and their response to climate change. A topographically controlled ice flow switch near a glacier margin was recently documented at Brei & eth;amerkurjokull, southeast Iceland, where the central flow unit migrated eastward in response to variations in subglacial topography and the influence of Jokulsarlon glacial lagoon. This site provides an opportunity to study the geomorphic response to ice-margin reconfiguration. Investigating contemporary processes can offer valuable insights into analogous landforms created during the deglaciation of palaeo-ice sheets. The landform assemblage and topographic setting of our Icelandic study site is compared to a palaeo-example from Alberta, Canada, which was once covered by the Laurentide ice sheet. Uncrewed aerial vehicle-(UAV) derived data was used to assess the geomorphic response to this switching and related processes across a 1.5 km2 area of the central flow unit which deglaciated between 2010 and 2023. From 2010 to 2017, the landscape featured streamlined subglacial material, a stable subglacial esker system and proglacial lakes (Landsystem A), shifting to a spillway-dominated system between 2018 and 2023 (Landsystem B). Since 2018 this section of Brei & eth;amerkurjokull has been retreating across a reverse slope bed, resulting in the formation of quasi-annual ice-marginal spillways. Meltwater impoundment at the ice margin, formed ice-contact lakes which eventually initiated ice-margin parallel spillways draining proglacial meltwater along the local landsurface gradient, towards Jokulsarlon. As the ice retreats, an ice-contact lake forms again at the new margin and initiates the erosion of the next ice-marginal spillway. The geomorphological signature demonstrates how subglacial topography and ice-flow switching can significantly influence ice and meltwater dynamics. Since the glacier flow-switch, part of the central unit is now lake-terminating with areas of the margin evolving into a stagnant system, as it is now cut off from the accumulation centre. Therefore, Landsystem B could be analogous to regions of ice stream shut down and where ice masses retreated across reverse slope beds. For example, the Pakowki Lake region of Southeastern Alberta displays a similar landform assemblage and is presented as a palaeo-example in this work. Such insights are important for assessing the efficacy of numerical models in reconstructing the finer scale dynamics of past ice sheets during retreat.
英文关键词Glacial geomorphology; Ice marginal channels; Ice -flow switching; Iceland; Laurentide Ice Sheet; UAV
语种英语
WOS研究方向Physical Geography ; Geology
WOS类目Geography, Physical ; Geosciences, Multidisciplinary
WOS记录号WOS:001224987600001
来源期刊GEOMORPHOLOGY
文献类型期刊论文
条目标识符http://gcip.llas.ac.cn/handle/2XKMVOVA/306195
作者单位Queens University Belfast; University of Aberdeen; Sheffield Hallam University
推荐引用方式
GB/T 7714		 . Geomorphological signature of topographically controlled ice flow-switching at a glacier margin: Breiðamerkurjokull (Iceland) as a modern analogue for palaeo-ice sheets[J],2024,454.
APA (2024).Geomorphological signature of topographically controlled ice flow-switching at a glacier margin: Breiðamerkurjokull (Iceland) as a modern analogue for palaeo-ice sheets.GEOMORPHOLOGY,454.
MLA "Geomorphological signature of topographically controlled ice flow-switching at a glacier margin: Breiðamerkurjokull (Iceland) as a modern analogue for palaeo-ice sheets".GEOMORPHOLOGY 454(2024).
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