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Lookup NU author(s): Dr Stuart Dunning
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
In glacial environments particle-size analysis of moraines provides insights into clast origin, transport history, depositional mechanism and processes of reworking. Traditional methods for grain-size classification are labour-intensive, physically intrusive and are limited to patch-scale (1m2) observation. We develop emerging, high-resolution ground- and unmanned aerial vehicle-based ‘Structure-from-Motion’ (UAV-SfM) photogrammetry to recover grain-size information across a moraine surface in the Heritage Range, Antarctica. SfM data products were benchmarked against equivalent datasets acquired using terrestrial laser scanning, and were found to be accurate to within 1.7 and 50mm for patch- and site-scale modelling, respectively. Grain-size distributions were obtained through digital grain classification, or ‘photo-sieving’, of patch-scale SfM orthoimagery. Photo-sieved distributions were accurate to <2mm compared to control distributions derived from dry-sieving. A relationship between patch-scale median grain size and the standard deviation of local surface elevations was applied to a site-scale UAV-SfM model to facilitate upscaling and the production of a spatially continuous map of the median grain size across a 0.3 km2 area of moraine. This highly automated workflow for site-scale sedimentological characterization eliminates much of the subjectivity associated with traditional methods and forms a sound basis for subsequent glaciological process interpretation and analysis.
Author(s): Westoby MJ, Dunning SA, Woodward J, Hein AS, Marrero SM, Winter K, Sugden DE
Publication type: Article
Publication status: Published
Journal: Journal of Glaciology
Print publication date: 01/12/2015
Online publication date: 26/11/2015
Acceptance date: 10/10/2015
Date deposited: 27/11/2015
ISSN (print): 0022-1430
ISSN (electronic): 1727-5652
Publisher: International Glaciological Society
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