Testing the extent and timing of past glaciations on the largest sub-Antarctic island, South Georgia

The sub-Antarctic islands are ideally placed to investigate past ice and climate changes, with records of their ancient glaciation important for understanding various aspects of the Earth system. Due to the islands' unique location between warm-maritime and cold-polar climates, the size of sub-Antarctic ice-cap advances provide a potentially valuable means of calibrating the sensitivity of ice-sheet models, ensuring the climate parameters used to force them are realistic and the outputs 'good' for the future. Variations in the scale and timing of glacial events can also provide critical information on the mechanisms and phasing of climate changes between regions and hemispheres. The same data constrain the whereabouts and persistence of glacial refugia, and inform biologists on the geological conditions governing the evolution and diversity of life in the Southern Ocean.
To improve ice-sheet models, explain patterns of climate change, and interpret the biodiversity of the world's oceans, information on sub-Antarctica's glacial past is required. However, fundamental questions relating to the age, magnitude, and number of past glaciations remain unanswered. For the largest sub-Antarctic island, South Georgia, at least one major glacial advance is already known from ice-carved troughs and sediment ridges (moraines) found on the sea-floor of the shallow shelf surrounding the island today. Yet its age is unknown. As in other parts of Antarctica, the most recent episode of glaciation - The Last Glacial Maximum - is likely to have left behind the best record of ice-cap advance and melting. However, even here, there is no consensus, with two conflicting hypotheses prevailing: one suggesting a limited ice extent, restricted to the near-shore fjords; the other proposing that the ice cap was extensive, reaching the outer parts of the shelf around most of the island. Answers to which hypothesis is correct lie in the study of the submarine topography and sediments, which have yet to be investigated in any detail.
This project proposes a pioneering study to examine the extent and timing of past glaciations on South Georgia, from a marine perspective, for the first time. I will provide a robust test of the hypotheses that, either: (i) the Last Glacial Maximum ice cap was of restricted extent and thus that one or more major ice cap glaciations that reached outer shelf limits pre-date the last glacial period; or that (ii) the Last Glacial Maximum ice cap was extensive, and a chronology of retreat is recorded in the shelf's landscape and sediments.
Existing and newly-collected sonar bathymetry data will be utilised to map out the glacial features on the South Georgia shelf in unprecedented detail. Six sediment cores, among the first recovered from the shelf, will be analysed and dated. The project will target moraines marking the limits of former ice-caps, from the shelf edge to the coastal fjords. I will determine the age of the most extensive glaciation, and the age of intermediate retreat or terminal limits. Physical analyses of sediments will reconstruct environmental conditions during and since the Last Glacial Maximum, to the present day, and perhaps through older cold or warm periods. Resolving the number and extent of former shelf glaciations preserved in sub-Antarctic records will be a major outcome of the project, as will vital new information on the behaviour and reach of the Last Glacial ice cap.
New records will be set in the context of Earth's climate and evolutionary histories, and form the first marine palaeo-constraints on sub-Antarctic glaciation, benefiting modellers, climate scientists and biologists. The project will also provide baseline geological data for use by habitat mapping projects and fisheries. This research will shed new light on Southern Ocean ice and climate history, and set a new agenda for future study of past glacial change in the near-polar regions.

A. Who will benefit from this research?
Academics: This research will benefit glaciologists predicting the impacts of future climate change on the planet, especially those modelling ice sheets in the Southern Hemisphere who require palaeo-data to constrain simulations. It will serve biologists mapping the biodiversity of the South Georgia shelf, where the glacial history is critical for interpreting the evolution of marine fauna. Climatologists will benefit from new data studying the forcing of glacial changes, with the potential for insights into the regional and global climate system. Habitat mappers who require details of seabed geology to develop habitat models, will also be direct beneficiaries of this work.
Government/Industry: The Government of South Georgia and South Sandwich Islands (GSGSSI) will benefit from new geological survey in the protected South Georgia Maritime Zone (SGMZ). Via improved habitat and biodiversity information, this research will directly impact upon management of the marine realm. Fisheries will have access to baseline geological data currently unavailable for the SGMZ. Environmental managers can also use new results to place recent glacial retreat into long-term context; glacier recession has come at environmental cost through the spread of invasive species, and further glacier melting is a key issue facing management of the island.
Society: Work on glacier change, particularly through improving constraints on ice-sheet models has impacts for society as a whole because of the risk of future ice-sheet change and sea-level rise. Schools and a work experience student will benefit from post-cruise activities, while museums will benefit from a new non-specialist publication. As an UK overseas territory, South Georgia also possesses a history of science exploration that is relevant to all of British society.
Project: The project will benefit PI Graham and his collaborators. Work will foster relations between NERC centres (BAS), facilities (e.g. BOSCORF) and partner universities in Durham and Leipzig.

B. How will they benefit from this research?
Academia: Ice sheet modellers will be provided with key datasets for use in future models. They will be kept informed of results at meetings, through the scientific literature, and via the SCAR-ACE Community Ice Sheet project. Key datasets will be communicated to a team of biologists working on South Georgia's marine biodiversity. Constraints on the timing and extent of shelf glaciations will be integrated with the interpretation of recent biodiversity surveys on the shelf, via planned meetings and a workshop, to shed light on the evolution of marine life in sub-Antarctic waters. Climate scientists and habitat mappers will be provided with new geological records, delivered through online databases, scientific papers, meetings (e.g. the International Forum on the sub-Antarctic) and a workshop, which will improve knowledge of past climates, and help produce better habitat models.
Government/Industry: Bathymetry and core data will be provided to the GSGSSI, UKHO and fisheries, via online metaservers (e.g. PANGAEA) and an existing online GIS database run by the South Georgia government. New baseline data on the geology of the shelf will be of wide benefit to industry, and work with biologists will help in future conservation decisions on South Georgia's marine ecosystems.
Society: Schools will benefit from interaction with polar science. A work experience student will have the opportunity to participate in a placement to gain experience of academic life. A non-specialist brochure will spread results widely, via the South Georgia and SPRI museums.
Project: The project will allow the proponent to further develop skills in marine geoscience research, gain experience as a PI, develop skills in managing projects and budgets, and benefit from the opportunity to convey results through journals, impact activities, and conferences.