Surge Forth: Understanding glacier dynamics where the Scottish Highlands meet the Lowlands

Overview

Reconstructing the former geometry and behaviour of glaciers and ice caps is important to understand how contemporary ice masses will respond to ongoing climate change [1]. The West Highland Icefield (WHI) of Scotland existed ca. 13.0–11.5 ka BP and was a transfluent ice-cap complex similar in size to present-day Vatnajökull in Iceland, or the ice-covered portion of Svalbard. It is generally assumed that the advance–retreat behaviour of the WHI was driven by climate change, and that its maximal extent was largely synchronous as a function of enhanced climate cooling during the Younger Dryas Stadial [2,3]. Recently, however, this notion has been challenged, with the possible identification of surge-type glaciers draining the Younger Dryas WHI [4]. From a palaeoclimatic perspective, it is vital to know whether glacier-front fluctuations resulted from (external) climate forcing or (internal) dynamic instabilities, such as surging. This PhD doctoral training project will address this question by examining the landform and sediment record and establish an advance-retreat chronology for several, unusually large, former outlet glaciers in Central Scotland thought to have surged during the Younger Dryas Stadial. Comparing this with evidence from present-day surging glaciers, and other glacier margins known not to have surged, will allow the glacier dynamics of former ice-fields and ice-caps to be better understood and, crucially, will also develop a toolkit for identifying surge-type glaciers in the wider palaeo-record.

This project will focus on the large but little-studied outlet glaciers of the former Scottish WHI draining the Gare Loch, Teith and Forth catchments as well as the well-dated Lomond Glacier [6,7]. These low-gradient glaciers were the largest outlets of the whole WHI and transferred large volumes of ice from the Highlands of Stirlingshire and Argyll to the Lowlands of central Scotland. Two of these glaciers also terminated in water bodies. Much like the largest lobes of Vatnajökull and Svalbard’s ice caps, we predict that these outlets were instability-driven surge-type glaciers [4]. Importantly, if Scottish glacier fluctuations are found not to be climatically driven, their former extent and behaviour should not be used in climatic reconstructions – yet the Lomond, Forth and Teith glaciers all currently constitute type-sites for the timing and palaeoenviroment of the Younger Dryas Stadial in Scotland [3,6-8].

The key aims of this PhD research project will be to:
• Map and characterise the different sediment-landform assemblages associated with these adjacent former glaciers.
• Determine a suite of diagnostic features relating to climatically driven or dynamically driven (surging) glacier fluctuations in Scotland, for use by Quaternary scientists.
• Establish a relative chronology of events using established geomorphological relationships and field techniques.
• Test this chronology using cosmogenic-nuclide exposure age dating and statistical modelling, supported by radiocarbon dating where possible.
• Explore the reasons for matches / mismatches between the advance-retreat chronologies at adjacent WHI outlet glaciers (Gare Loch, Lomond, Forth, Teith).

The successful student will be encouraged to present at conferences and publish journal articles at well-defined stages of their research. The outcomes of this research will feed into numerical ice-sheet models and international databases – part of wider projects to understand the glacial history of NW Europe.

Methodology

The research methodology will be interdisciplinary and innovative, supervised by leading experts in their fields. The studentship will involve a combination of desktop-, laboratory- and field-based research; collecting valuable geological data; conducting detailed sedimentological analyses; and constructing geochronological models (overseen and supported by supervisors). The project will use existing high-resolution digital-elevation models (LIDAR and radar) and previously collected bathymetric and geophysical data (from Loch Lomond) collated in GIS environments and 3D-visualisation packages to produce digital scale-independent map-based outputs. A range of field-sampling and Quaternary dating techniques will be deployed in Year 1 & 2. Fieldwork in Iceland or Svalbard to visit and study modern-day surging glaciers is envisaged in Year 2.

The studentship will be based in Stirling, with support from the University of St Andrews, but the student will also have access to world-class laboratory facilities at the Scottish Universities Environmental Research Centre (SUERC) in East Kilbride, as well as other state-of-the-art facilities if/when appropriate. The successful candidate will receive dedicated training in each of the complementary techniques by the supervisory team, and she/he will be expected to contribute to the evolution and enhancement of the methodology throughout the project.

Project Timeline

Year 1
• Systematic review of previous work and methodological capabilities
• Research design and software training
• Doctoral training methods and skills training programme
• Scottish fieldwork (1): landform-sediment mapping and sedimentological coring studies (Lomond, Forth, Teith, Gare Loch catchments)
• Establish relative chronological framework
• Scottish fieldwork (2): terrestrial cosmogenic nuclide (TCN) sampling
• PhD progression paper (Yr1)
• UK Conference presentation (Sep 2022)
Year 2

• Advanced skills training
• TCN preparation and lab analyses (SUERC)
• Iceland / Svalbard fieldwork
• Lab-based sediment analysis (PSA, marine carbonates, mineral separation, etc)
• Manuscript preparation & submission
• Yr2 Progression review (Sept 2023)

Year 3

• Final sedimentological analyses
• Chronological / statistical modelling
• Data assimilation and thesis ‘workshop’
• International conference presentation

Year 3.5

• Presentation of results to stakeholders
• Focused thesis write-up
• mock oral exam; manuscript preparation
• Finalise & submit thesis for PhD examination

Training
& Skills

Training in specialist and complementary transferable skills is the most important aspect of a PhD programme. This PhD comes with a generous £10k Research and Training Support Grant (see below) to cover fieldwork, internal and external training, analytical costs and consumables. It will also provide the means to travel to/from sites – allowing the successful candidate to benefit from F2F supervision in more than one UK academic institution (Stirling & St Andrews).

Over the 3.5-year programme specialist training will be provided in: GIS, geomorphological mapping; geophysical data acquisition and interpretation; sediment analysis techniques; TCN sampling; sample preparation and analysis; construction of chronological models, including using Oxcal / Bayesian methods; statistical techniques using R; bespoke software training for high-quality oral presentation, manuscript and poster production.

As a NERC-IAPETUS2 student, in Year 1, she/he will also receive more generic doctoral training in research skills and techniques; health and safety in the workplace; effective research environment; research management; personal effectiveness; communication skills; manuscript and grant writing; networking and team-working; thesis troubleshooting; interview preparation and career management. The student will join a vibrant community of staff and postgraduate students at the University for Stirling (BES) and will also be part of the wider IAPETUS postgraduate groups at St Andrews. The primary supervisor will meet with the student at least monthly; the supervisor team will meet with the student at least three times a year.

References & further reading

[1] IPCC, 2018. Global warming of 1.5C. An IPCC Special Report.[2] Sissons, J.B. 1979. Nature, 280: 199-203.[3] Bickerdike, H.L. et al., 2018. Journal of Quaternary Science 33: 1-54.[4] Benn, D.I. 2021. Scottish Geographical Journal. DOI: 10.1080/14702541.2021.1922738[5] Golledge, N.R. et al. 2008. Quaternary Science Reviews, 888-904.[6] MacLeod, A. et al. 2011. Global and Planetary Change, 79: 264-274.[7] Evans, D.J.A. 2021. In Ballantyne, C.K. & Gordon, J.E. (eds) Landscape and Landforms of Scotland, Springer Nature: 407-424.[8] Ballantyne, C.K. et al. 2021. In Ballantyne, C.K. & Gordon, J.E. (eds) Landscape and Landforms of Scotland, Springer Nature: 53-96.

Further Information

Dr Tom Bradwell
tom.bradwell@stir.ac.uk

Prof Doug Benn
dib2@st-andrews.ac.uk

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