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Lookup NU author(s): Dr Nick CutlerORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
We explore the effect small-scale surface features have on influencing the morphology and grain size distribution (GSD) of tephra layers within the Quaternary stratigraphy of sub-polar landscapes. Icelandic thúfurs, small cryogenic earth mounds, are used to assess how and why the morphology and GSD of tephra layers vary over such formations. Through measurement of tephra layer thickness and grain size distribution, Hekla 1947 and Grímsvötn 2011 tephra layers are analysed. Results indicate that such microtopographic features do indeed alter the form of tephra deposits and therefore the tephra layer that is preserved in the stratigraphy. Tephra thickness is significantly greater in hollows than on the thúfur crests. There is greater variation in tephra thickness measurements from thúfur in comparison to control measurements from a surface where thúfur are absent. Thúfur crests contain larger grain sizes than hollows, for both H1947 and G2011 tephras, however this was only statistically significant for the G2011 tephra. Such morphological patterns are thought to arise from an interplay of tephra characteristics, altered topography from the thúfur formations and earth surface processes operating at the sites. This study provides insight into the potential of tephra layer morphology and internal structures as indicators of Quaternary landforms and processes. Additionally, it provides important context for the appropriate sampling of tephra layers to infer volcanological processes, as the characteristics of preserved layers do not necessarily reflect those of the original fallout.
Author(s): Thompson PIJ, Dugmore AJ, Newton AJ, Streeter RT, Cutler NA
Publication type: Article
Publication status: Published
Journal: Boreas
Year: 2021
Volume: 51
Issue: 2
Pages: 317-331
Print publication date: 20/04/2022
Online publication date: 25/09/2021
Acceptance date: 14/08/2021
Date deposited: 01/09/2021
ISSN (print): 0300-9483
ISSN (electronic): 1502-3885
Publisher: Wiley-Blackwell Publishing Ltd
URL: https://doi.org/10.1111/bor.12557
DOI: 10.1111/bor.12557
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