Characterisation, timing and source analysis of the White Bridge boulder deposit in the Cairngorm Mountains, Scotland
PhD Candidate: Dakota Youngeagle
Supervisor: Dr Sam Kelley
Funded by: Irish Research Council (now Research Ireland)
Abstract:
The Cairngorm Mountains of central Scotland contain a wealth of glacial geomorphic features relating to the recession of first the British Irish Ice Sheet (Brazier et al., 1998; Phillips et al.,2006), and later, locally sourced glaciers during the latest Pleistocene and possibly early Holocene (Everest and Kubik, 2006; Kirkbride et al., 2014; Standell, 2014). These landforms and deposited sediments provide a record of landscape change during a time of shrinking ice masses in response to warming climate. One feature of modern ice recession is the formation of proglacial lakes, formed by glacial meltwater infilling topographic depressions left by receding glaciers (Brazier et al., 1998). Known as glacial lake outburst floods (GLOF), the release of water from these sediment or ice dammed lakes, frequently rapidly, is a major hazard in mountain communities today (ex. Harrison et al., 2018). The upper Dee Valley, near White Bridge, in Scotland contains a well-preserved deposit theorised to be the result of a paleo-GLOF (Wickham-Jones et al., 2020), which is of interest, because the timing of deposition can be determined by 10Be cosmogenic exposure dating and flood discharge estimations. Together with the determination of the lithologies of the deposit this gives an educated estimate of the size of the GLOF as well as possible provenance of the source rock. This study will focus on (1) the characterisation of the deposit in terms of area, size of clasts, lithology and provenance; (2) the determination of the timing of deposition and; (3) the estimation of the volume of the GLOF. This work may be able to provide context for current hazards facing society today. Furthermore, the timing of the White Bridge flood is believed to overlap with early hunter-gatherer activity in the area, thus there is archaeological interest in the early human response to natural hazards.
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