PREDICTING AND INVESTIGATING SUBGLACIAL LAKES OF THE FORMER BRITISH AND FENNOSCANDIAN ICE SHEETS
Lead Research Organisation:
University of Sheffield
Department Name: Geography
Abstract
The discovery that large lakes exist at the base of the Antarctic Ice Sheet and that these lakes can rapidly drain has major implications related to meltwater routing and supply and thus ice-sheet dynamics. Recent satellite observations show that subglacial lakes are very active, and can perturb the water system rapidly on annual or shorter time-scales, while at Byrd Glacier a direct link between water drainage and ice flow acceleration has been demonstrated. With over 250 lakes now known to exist under the Antarctic Ice Sheet there has also been rising interest in exploring these subglacial environments to look for evidence of life and to investigate their potential as long-term archives of climate change. This interest is demonstrated by three separate US-, Russian- and UK-led programs which aim to drill into these lakes. Despite the growing importance attached to studying subglacial lakes in Antarctica, the identification and study of palaeo subglacial lakes from former ice sheets has been neglible, with even fundamental questions related to their geological signatures remaining elusive. Yet investigations of palaeo subglacial lakes offers significant advantages because we have comprehensive information about the bed properties, they are logistically more accesable (i.e. on foot instead of 3 km long drills) and we can sample and examine the sediments with ease. If I can find palaeo subglacial lakes then I have the potential to make huge leaps in knowledge with regard to the topographic context and hydrological pathways that the phenomena form a part of; essentially I gain spatial and sedimentological information in relation to contemporary subglacial lake investigations and lose out on the short time dynamics. This proposal offers a pioneering study that aims to invigorate research on subglacial lakes by answering two major research questions: (1) can we successfully predict and identify subglacial lakes of the former British and Fennoscandian Ice Sheets during the last glaciation?; and (2) What impact did subglacial lakes have on meltwater routing and supply and thus ice sheet dynamics? The study will utilise GIS and numerical ice sheet modelling to predict where subglacial lakes may have ocurred in the former British and Fennoscandian Ice Sheets and then the identification and evaluation of some of these former subglacial lakes using sedimentological, stratigraphic and geomorphological techniques. The formulation of a diagnostic set of criteria for identying palaeo subglacial lakes is a major research objective for the project and will be first such attempted. Once identified further research will concentrate on the links between subglacial lakes and ice sheet dynamics, specifically related to meltwater routing and the relationship with ice streams. It is anticipate that findings arising from this work and the lakes I discover will stimulate many other researchers to exploit the record of palaeo subglacial lakes and set a new agenda for glaciological thinking of how basal water exerts a control on ice flux and routing.
People |
ORCID iD |
| Stephen Livingstone (Principal Investigator) |
Publications
Livingstone S
(2016)
Morphological properties of tunnel valleys of the southern sector of the Laurentide Ice Sheet and implications for their formation
in Earth Surface Dynamics
Livingstone S
(2013)
Modelling North American palaeo-subglacial lakes and their meltwater drainage pathways
in Earth and Planetary Science Letters
Livingstone S
(2015)
Discriminating between subglacial and proglacial lake sediments: an example from the Dänischer Wohld Peninsula, northern Germany
in Quaternary Science Reviews
Livingstone S
(2012)
Theoretical framework and diagnostic criteria for the identification of palaeo-subglacial lakes
in Quaternary Science Reviews
Livingstone S
(2015)
An ice-sheet scale comparison of eskers with modelled subglacial drainage routes
in Geomorphology
Livingstone S
(2013)
Potential subglacial lake locations and meltwater drainage pathways beneath the Antarctic and Greenland ice sheets
in The Cryosphere
Livingstone SJ
(2016)
Discovery of relict subglacial lakes and their geometry and mechanism of drainage.
in Nature communications
| Description | 1. Developed a GIS methodology for predicting subglacial lakes and their drainage beneath modern and former ice sheets (Livingstone et al. 2013a,b). The method was validated against the known subglacial lake inventory for the Antarctic Ice Sheet. It did a good job of recalling known lakes and also predicted many more lakes that are not observed. Likewise when applied to Greenland, where very few lakes have so far been found, we predict several thousand subglacial lakes. This suggests that thousands of lakes remain to be found, and these results therefore provide suitable targets for future geophysical surveys. When this approach was applied to the former North American Ice Sheet using an ensemble of modelled ice-surface and bed topographies I was able to examine where on the bed subglacial lakes were likely to have formed. The predictions form useful targets for detailed remote and field investigations. Moreover, the temporal evolution of lakes predicted suggests that many more subglacial lakes are likely to exist during ice-sheet deglaciation rather than advance. This suggest the hydrology of advancing and deglaciating ice sheets is different. 2. Provided a theoretical framework and diagnostic criteria for the identification of subglacial lakes in the geological record (Livingstone et al. 2012). This has helped to raise awareness about the potential for relict subglacial lakes to have existed beneath the former mid-latitude ice sheets. Diagnostic criteria were derived from modern observations, theory and process analogues. Although it still remains difficult to discriminate between subglacial and proglacial sediments, headway was made in using Optically Stimulated Luminescence dating to fingerprint subglacial lake sediments, and identifying landforms patterns indicative of repeated subglacial lake flood events (Livingstone et al., 2012, 2016). 3. The identification of former subglacial lakes and their drainage pathways in Alberta, Canada (Livingstone et al. 2016) and a possible former subglacial lake in northern Germany along the Baltic Coast (Livingstone et al. 2015). This involved sediment, landform and dating techniques. 4. The GIS method for predicting drainage beneath ice sheets was compared against mapped esker networks (residue of former subglacial meltwater flow) beneath the Laurentide Ice Sheet, North America (Livingstone et al. 2015). This allowed an investigation into esker deposition and preservation, which is the first time this has been done at the ice sheet scale. We find that the dominant modelled subglacial drainage routes do not in general conform to esker locations, and that eskers are predicted to form in small segments close to the ice margin. 5. Mapping of large meltwater channels (tunnel valleys) along the southern margin of the Laurentide Ice Sheet (Livingstone & Clark, 2016) supports gradual (rather than a single-event) formation of most tunnel valleys with secondary contributions from flood drainage of subglacial and or supraglacially stored water down individual tunnel valleys. The distribution and morphology of tunnel valleys is shown to be sensitive to regional factors such as basal thermal regime, ice and bed topography, timing and climate. |
| Exploitation Route | The results of this work could be used by the academic community to improve searches for subglacial lakes beneath modern and former ice sheets. In particular, the predictions and diagnostic criteria developed as part of this project is expected to kick-start further research into the subglacial hydrology of former ice sheets. The identification of subglacial lakes in the geological record will allow significant leaps in knowledge with regards to the topographic context and hydrological pathways that the phenomena form a part of. Moreover, the sediments of former subglacial lakes offer a potential archive of long-term Quaternary climate change, while their drainage signature will allow us to explore their influence on ice dynamics and ocean circulation. A next step might therefore be to drill into thick sediment packages associated with stable lake predictions in North America, e.g. Lake Ontario of Great Slave Lake. |
| Sectors | Education,Environment |
| Description | The results of this research have been wholly felt by academics who will be able to use the approaches and results developed during this grant to kick start this nascent research area. |
| Description | MOCA - Meltwater routing and Ocean-Cryosphere-Atmosphere response |
| Organisation | Meltwater routing and Ocean-Cryosphere-Atmosphere response |
| Country | Canada |
| Sector | Charity/Non Profit |
| PI Contribution | MOCA is an international network of collaborators. Their principal objective is to establish a constrained regional meltwater and iceberg discharge chronology for all major ice-sheets during the last deglaciation with well-defined error bars. The consequent objective is to establish a good conceptual understanding of the interactions between the cryosphere, ocean, and atmosphere associated with this chronology. I was invited to be an international participant by Lev Tarasov (Memorial University, Canada), who I have also formed a strong collaboration with. |
| Collaborator Contribution | Contribution of ice-sheet model data and intellectual advice. |
| Impact | Two papers: Livingstone, S.J., Storrar, R.D., Hillier, J.K., Stokes, C.R., Clark, C.D., Tarasov, L. 2014, Submitted. Investigating esker deposition and preservation from an ice-sheet scale comparison of modelled drainage directions with esker networks. Journal of Glaciology. Livingstone, S.J., Clark, C.D. and Tarasov, L. 2013. Modelling North American palaeo-subglacial lakes and their meltwater drainage pathways. Earth and Planetary Science Letters, 375, 13-33. |
| Start Year | 2012 |