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Lookup NU author(s): Dr Devin Harrison, Professor Neil RossORCiD, Professor Andrew RussellORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Sandur plains are extensive sedimentary bodies formed in proglacial settings by glaciofluvial processes. Icelandic sandar have been hypothesised to be comprised of thick alluvial successions that provide critical insight into the processes that contributed to their formation and evolution. However, to-date, most sandar research has focused on the analysis of sedimentary successions associated to topographically-confined and small-scale systems. These, however, do not capture the variety or scale of processes that influence sandar architecture. Therefore, detailed subsurface analysis of large-scale and unconfined sandar is vital to understand how these systems respond to fundamental drivers, such as: (i) glacier oscillations, and (ii) episodic sediment flux from glacier outburst floods (aka. jökulhlaups). We report an extensive, low-frequency (40 & 100 MHz) ground-penetrating radar (GPR) survey of the ice-proximal component of a large-scale (1300 km2) active sandur in southeast Iceland. A bright and continuous reflection (PR1) is identified within all radargrams and provides a boundary between pre-LIA and LIA to present-day sedimentation. GPR data reveals a ~50 m thick ice-proximal sediment wedge that is attributed to jökulhlaup and surge-related glaciofluvial activity during the Little Ice Age (LIA). An approximate rate of deposition of 0.2–0.65 m.a-1 has been calculated for the sediment wedge above PR1. Furthermore, we propose an extensive, sandur-wide, pre-LIA ice marginal limit of Skeiðarárökull, southeast Iceland, based on observations reported here and in previous work. a−1 has been calculated for the sediment wedge above PR1. Furthermore, we propose an extensive, sandur-wide, pre-LIA ice marginal limit of Skeiðarárökull, southeast Iceland, based on observations reported here and in previous work. ~1300km2 a−1 has been calculated for the sediment wedge above PR1. Furthermore, we propose an extensive, sandur-wide, pre-LIA ice marginal limit of Skeiðarárökull, southeast Iceland, based on observations reported here and in previous work.
Author(s): Harrison D, Ross N, Russell AJ, Jones S
Publication type: Article
Publication status: Published
Journal: Journal of Quaternary Science
Year: 2023
Volume: 38
Issue: 6
Pages: 947-969
Print publication date: 02/08/2023
Online publication date: 29/03/2023
Acceptance date: 24/02/2023
Date deposited: 29/03/2023
ISSN (print): 0267-8179
ISSN (electronic): 1099-1417
Publisher: John Wiley & Sons Ltd.
URL: https://doi.org/10.1002/jqs.3518
DOI: 10.1002/jqs.3518
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